Capron v. Massachusetts Attorney General ( 2019 )


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  •           United States Court of Appeals
    For the First Circuit
    No. 17-2140
    ERIN CAPRON; JEFFREY PENEDO; CULTURAL CARE, INC., d/b/a Cultural
    Care Au Pair,
    Plaintiffs, Appellants,
    v.
    OFFICE OF THE ATTORNEY GENERAL OF THE COMMONWEALTH OF
    MASSACHUSETTS; MAURA T. HEALEY, in her capacity as Attorney
    General of the Commonwealth of Massachusetts,
    Defendants, Appellees.
    APPEAL FROM THE UNITED STATES DISTRICT COURT
    FOR THE DISTRICT OF MASSACHUSETTS
    [Hon. Indira Talwani, U.S. District Judge]
    Before
    Torruella, Lynch, and Barron,
    Circuit Judges.
    Joan A. Lukey, with whom Justin J. Wolosz and Choate Hall &
    Stewart LLP were on brief, for appellants.
    Ryan P. McManus, Donna A. Mizrahi, and Hemenway & Barnes LLP
    on brief for Host Families, amici curiae.
    Faith Kalman Reyes and Verdi & Ogletree PLLC on brief for the
    Alliance for International Exchange, amicus curiae.
    Michael Shih, Attorney, Appellate Staff, Civil Division, U.S.
    Department of Justice, Joseph H. Hunt, Assistant Attorney General,
    Andrew E. Lelling, United States Attorney, and Alisa B. Klein,
    Attorney, Appellate Staff, Civil Division, on brief for the United
    States, amicus curiae.
    Robert E. Toone, Assistant Attorney General, with whom Maura
    T. Healey, Attorney General of Massachusetts, and Elizabeth A.
    Kaplan, Assistant Attorney General, were on brief, for appellees.
    Audrey R. Richardson, Greater Boston Legal Services,
    Catherine Fisher, Marley Brumme, Meredith B. Stewart, Gillian B.
    Gillers, Southern Poverty Law Center, Benjamin Richard Botts,
    Centro de los Derechos del Migrante, Inc., Rocío Alejandra Avila,
    and National Domestic Workers Alliance, on brief for Worker
    Organizations, amici curiae.
    Dawn L. Smalls, Byron Pacheco, Sean P. Rodriguez, Juan P.
    Valdivieso, Boies Schiller Flexner LLP, David Seligman, and
    Towards Justice, on brief for Sarah Carolina Azuela Rascon and All
    Other Similarly Situated Current and Former Au Pairs, amici curiae.
    December 2, 2019
    BARRON,       Circuit    Judge.           This    appeal     concerns    the
    relationship between the wage and hour rights that Massachusetts
    confers on in-home childcare services providers and the operation
    of   a    federal        program   that    promotes       international          cultural
    exchange.          The    United     States    Department           of   State    ("DOS")
    administers this federal program, which we will refer to as the
    "Au Pair Program."           Through it, foreign nationals may obtain a
    special type of visa and then be placed with host families in the
    United States, so that the foreign nationals may provide in-home
    childcare services to the host families while they also pursue
    their post-secondary school studies.
    The issue that we must resolve in this appeal arises in
    connection with a lawsuit that was filed on August 31, 2016 in the
    United States District Court for the District of Massachusetts
    against     the     Attorney       General        of    Massachusetts        ("Attorney
    General").         The plaintiffs are Cultural Care, a DOS-approved
    private placement agency based in Massachusetts, as well as Erin
    Capron and Jeffrey Penedo, who each reside in Massachusetts and
    with whose families Cultural Care has in the past placed foreign
    national visa holders through the Au Pair Program.
    The    plaintiffs       contend       that       the   Au   Pair    Program
    impliedly preempts Massachusetts from requiring host families to
    comply with its wage and hour laws as employers of the visa holders
    - 3 -
    who provide them childcare services through that program. The
    plaintiffs seek declaratory and injunctive relief.
    The Attorney General moved to dismiss the plaintiffs'
    complaint.       The District Court granted the motion on August 1,
    2017.       The next day, the District Court ordered the plaintiffs'
    case dismissed.       The District Court also denied the plaintiffs'
    motion for reconsideration of the order of dismissal or, in the
    alternative, for leave to amend the complaint.
    The   plaintiffs   timely     appealed   both   the   order   of
    dismissal and the denial of the motion for reconsideration or, in
    the alternative, for leave to amend the complaint.            We now affirm.1
    I.
    We first describe the relevant federal and state bodies
    of law.      We start with the federal measures.       We then turn to the
    state law measures.
    A.
    The federal measures consist of authorizing legislation
    and implementing regulations.        We consider each type of federal
    measure in turn.
    1
    Our conclusion accords with the only other precedent to
    address the issue.   See Beltran v. InterExchange, Inc., 
    176 F. Supp. 3d 1066
    , 1083–84 (D. Colo. 2016).
    - 4 -
    1.
    Nearly sixty years ago, Congress enacted the Fulbright-
    Hays Act.     See Pub. L. No. 87-256 § 102, 
    75 Stat. 527
     (1961)
    (codified at 
    22 U.S.C. § 2452
    ).     That statute authorized a series
    of "educational" and "cultural exchanges."      
    Id.
       The preamble to
    the statute describes Congress's purposes in authorizing these
    cultural exchanges as follows:
    [T]o enable the Government of the United
    States to increase mutual understanding
    between the people of the United States and
    the people of other countries by means of
    educational   and    cultural   exchange;   to
    strengthen the ties which unite us with other
    nations by demonstrating the educational and
    cultural    interests,    developments,    and
    achievements of the people of the United
    States    and   other    nations,    and   the
    contributions being made toward a peaceful and
    more fruitful life for people throughout the
    world; to promote international cooperation
    for educational and cultural advancement; and
    thus to assist in the development of friendly,
    sympathetic, and peaceful relations between
    the United States and the other countries of
    the world.
    
    22 U.S.C. § 2451
    .
    The Fulbright-Hays Act provided funding for a series of
    cultural exchange programs to bring foreign nationals to this
    country and also created the J-Visa.     See Pub. L. No. 87-256 § 109
    (codified at 
    8 U.S.C. § 1101
    (a)(15)(J)).       The provision of the
    statute that creates the J-Visa states that, to qualify for it, a
    person must be:
    - 5 -
    an alien having a residence in a foreign
    country which he has no intention of
    abandoning who is a bona fide student,
    scholar,    trainee,    teacher,    professor,
    research assistant, specialist or leader in a
    field of specialized knowledge or skill, or
    other person of similar description, who is
    coming temporarily to the United States as a
    participant in a program . . . for the purpose
    of   teaching,   instructing   or   lecturing,
    studying, observing, conducting research,
    consulting, demonstrating special skills or
    receiving training.
    
    8 U.S.C. § 1101
    (a)(15)(J).
    The DOS is currently responsible for implementing the
    provisions of the Fulbright-Hays Act that we have just described.
    See 
    22 C.F.R. § 62.1
    .     The DOS does so through regulations that
    govern different types of "exchange visitor programs."              See 
    id.
    §§ 62.3, 62.4; Exchange Visitor Program -- Au Pairs, 
    74 Fed. Reg. 15,844
     (Apr. 8, 2009) (to be codified at 22 C.F.R. pt. 62).               The
    "Exchange   Visitor   Program"   regulations     authorize   the    DOS    to
    designate only certain types of exchange programs as "exchange
    visitor programs."    See, e.g., 
    22 C.F.R. § 62.24
    (b) (authorizing
    designation    of   "exchange    visitor     programs   in   the    Teacher
    category");   
    id.
       § 62.31   (authorizing    designation    of    "au   pair
    exchange program[s]").2
    2 The "participants" in a DOS-designated exchange visitor
    program are also called "exchange visitors" in the regulations.
    
    22 C.F.R. §§ 62.1
    (b), 62.2 (defining "Exchange Visitors").
    - 6 -
    Participants in these "exchange visitor programs" can
    receive "J-1" visas. 
    8 C.F.R. § 214.1
    (a)(2) (designating visas
    provided pursuant to 
    8 U.S.C. § 1101
    (a)(15)(J) as "J-1" visas).    A
    J-1 visa is a nonimmigrant visa that permits a foreign national to
    come to the United States for "teaching, instructing or lecturing,
    studying,      observing,    conducting     research,    consulting,
    demonstrating special skills, or receiving training."      
    8 U.S.C. § 1101
    (a)(15)(J); 
    8 C.F.R. § 214.1
    (a)(2).    Persons who possess J-1
    visas "may be employed" in the United States only through "exchange
    visitor programs." 8 C.F.R. § 274a.12(b)(11).
    The DOS "Exchange Visitor Program" regulations provide
    that exchange visitor programs are "conduct[ed]" by "sponsors[.]"
    
    22 C.F.R. §§ 62.3
    , 62.31(c).     The sponsors are private placement
    agencies, such as the one that is a plaintiff in this case:
    Cultural Care.
    The "Exchange Visitor Program" regulations authorize
    the DOS to "designate" the private placement programs "conducted"
    by these sponsors as "exchange visitor programs."       
    Id.
     §§ 62.3,
    62.31 (a)-(c).     The DOS's designation authorizes the sponsor to
    "select[]" foreign nationals to be "participants" in its exchange
    visitor program, which in turn permits the participants to be
    placed in employment settings in this country pursuant to their
    J-1 visas.    See id. § 62.31(c)-(d).
    - 7 -
    Sponsors "must remain in compliance with all local,
    state, and federal laws, and professional requirements necessary
    to carry out the activities for which [they are] designated,
    including    accreditation          and     licensure,    if    applicable."         Id.
    § 62.9(c). Regardless of the nature of the DOS-designated exchange
    visitor program, the sponsor must, among other things, appoint
    "Responsible Officers."             Id. § 62.11(a).
    If    the    exchange     visitor     program     has     "an   employment
    component,"       the    "Responsible       Officers"    must     have    "a   detailed
    knowledge     of    federal,        state    and   local       laws    pertaining     to
    employment."       Id.    Sponsors of exchange visitor programs that have
    an   employment         component    must    provide     "clear       information    and
    materials"    to    program     participants,        including         information    on
    "employee rights and laws, including workman's compensation."                        Id.
    § 62.10(b)(9).
    The DOS "Exchange Visitor Program" regulations do not
    purport to regulate directly those for whom the participants in
    these exchange visitor programs work after the sponsors have placed
    them in a job.          See id. § 62.31.       The regulations -- with limited
    exceptions not relevant here -- directly regulate only the sponsors
    themselves. Id. The only sanctions that the regulations set forth
    that the DOS may impose on a sponsor are for its failure to meet
    one of its obligations under the regulations.                    Those sanctions --
    again, with limited exceptions not relevant here -- only concern
    - 8 -
    the   ability     of   the    sponsors      to   retain    or   renew     the   DOS's
    designation of the placement programs that they run as ones that
    qualify as "exchange visitor program[s]."                Id. §§ 62.31(n), 62.50.
    2.
    The DOS's "Exchange Visitor Program" regulations contain
    subsections that "govern" each type of exchange visitor program
    that the regulations encompass.               See §§ 62.20-.32.          The program
    types   include    ones      for   summer     workers,    au    pairs,    academics,
    teachers, and camp counselors.              See id.      The section of the DOS
    "Exchange Visitor Program" regulations at issue governs exchange
    visitor programs for "au pair participants."                      Id. § 62.31(a).
    These programs are also known as "au pair exchange program[s]."
    Id. § 62.31(c).
    In 1986, the United States Information Agency ("USIA"),
    which was -- until 1999 -- responsible for the implementation of
    the Fulbright-Hays Act, established au pair exchange programs on
    a two-year, pilot basis.           See Exchange Visitor Program, 
    59 Fed. Reg. 64,296
     (Dec. 14, 1994) (to be codified at 22 C.F.R. pt. 514)
    (describing the 1986 program); see also Foreign Affairs Reform and
    Restructuring Act of 1998, Pub. L. No. 105-277, div. G, §§ 1311-
    1314, 
    112 Stat. 2681
    , 2681-776 (codified at 
    22 U.S.C. §§ 6531
    -
    6533) (dissolving the USIA and transferring implementation of the
    Fulbright-Hays Act to DOS).           This two-year pilot, the USIA later
    - 9 -
    observed, had "rather non-specific program guidelines."               See 59
    Fed. Reg. at 64,296, 64,299 (describing the preexisting program).
    After the two-year trial period ended, the USIA decided
    not to designate the au pair exchange programs permanently due to
    a concern that "the programs were outside the Agency's statutory
    authority    to     oversee    educational       and    cultural     exchange
    activities."      Id.     Nevertheless,      because   of   the   substantial
    interest in the program, Congress enacted "special legislation" to
    "obligat[e]" the USIA to continue the programs.               Id.   Congress
    also directed the United States General Accounting Office ("GAO")
    to examine them.        See U.S. Gov't Accountability Office, GAO-90-
    61, U.S. Information Agency: Inappropriate Uses of Educational and
    Cultural Exchange Visas 19 (1990).
    A GAO report, issued in 1990, determined that the pilot
    au pair exchange programs were not consistent with the intent of
    the Fulbright-Hays Act.       Id.   The report questioned whether the au
    pair exchange programs were properly designated as employment or
    cultural programs -- and thus the report questioned which federal
    agency should run the programs.           Id.   The GAO report noted the
    concern expressed by the United States Department of Labor ("DOL")
    that the "au pair program violates the spirit of the J-visa
    statute" because "a 40-hour week constitutes full-time employment,
    and, as such . . . [t]hese [foreign] workers would normally have
    to receive certification from the [DOL] that enough qualified U.S.
    - 10 -
    workers    were   not   available    and     that    the   wages    and   working
    conditions attached to job offers would not adversely affect
    similarly employed U.S. workers."              Id.     Thus, the GAO report
    concluded, "[a]s currently structured, au pair programs would
    normally    be    subject    to     [DOL]     administrative        review   and
    certification."     Id. at 20.
    Notwithstanding the concerns raised in the GAO report,
    Congress directed the USIA, pursuant to a new statute, to continue
    to implement the au pair exchange programs "until [they] could be
    transferred to a more appropriate federal agency."                  59 Fed. Reg.
    at 64,296-97; see Eisenhower Exchange Fellowship Act of 1990, Pub.
    L. No. 101-454, 
    104 Stat. 1063
    .              In 1994, Congress passed the
    Technical Amendments to the State Basic Authorities Act, Public
    Law 103-415, which authorized the USIA "to promulgate regulations
    specifically governing the au pair programs."                59 Fed. Reg. at
    64,297.
    In 1994, the USIA promulgated interim final regulations
    "to govern the au pair programs [in ways that are] consistent with
    the provisions of the Fulbright-Hays Act."                 Id.     Those interim
    final regulations established the first iteration of what we refer
    to as the "Au Pair Program."        Id.
    The 1994 interim final regulations stated that "[a]u
    pair programs permit foreign nationals to enter the United States
    for a period of one year for the purpose of residing with an
    - 11 -
    American host family while participating directly in the home life
    of the family and providing limited childcare services."                 Id. at
    64,296.    They also contained a provision entitled "Stipend and
    hours,"    which   obliged    sponsors       to   "require   that   au     pair
    participants . . . are compensated" -- presumably by their host
    families, though the provision does not specify who must pay the
    participants for the childcare services that they provide -- "at
    a rate of not less than $155.00 per week."              Id. at 64,300.      The
    provision obliged sponsors to require that participants would
    receive weekly compensation at least equal to the wage due to them
    under the FLSA if the participants had provided the full amount of
    childcare services that they were permitted under the program to
    provide to their host family in a given week, regardless of whether
    the participants actually had done so.            In this way, the provision
    ensured that compensation for the participants would comply with
    the FLSA in the event that the DOL would deem the participants
    "employees" within the meaning of that statute.               Id. at 64,298
    (amending 
    22 C.F.R. § 514.31
    , though 
    22 C.F.R. § 514.31
     has since
    been redesignated).
    In 1995, the USIA revised that provision to oblige
    sponsors   to   "require     that   au    pair    participants   . . . [a]re
    compensated at a rate of not less than $115.00 per week." Exchange
    Visitor Program, 
    60 Fed. Reg. 8547
    , 8553 (Feb. 15, 1995) (to be
    codified at 22 C.F.R. pt. 514).          Once again, the USIA did so in a
    - 12 -
    manner that was intended to ensure that participants would not be
    paid less than the FLSA-prescribed minimum wage for domestic
    workers who qualified as "employees."               Id. at 8551.
    The USIA then revised this provision once more in 1997.
    The USIA did so this time in response, in part, to a formal
    determination by the DOL that au pair participants are "employees"
    within the meaning of the FLSA and thus that "au pair participants
    are covered under the provisions of the [FLSA] and therefore must
    receive federal minimum wage."           Exchange Visitor Program, 
    62 Fed. Reg. 34,632
    , 34,633 (Jun. 27, 1997) (to be codified at 22 C.F.R.
    pt. 514).
    The USIA at that time revised the "Stipend and hours"
    provision to instead be titled "Wages and hours."                 Id. at 34,634.
    That       provision   was   also   revised    at   that   time   to   state   that
    "[s]ponsors shall require that au pair participants . . . [a]re
    compensated at a weekly rate based upon 45 hours per week and paid
    in conformance with the requirements of the [FLSA] as interpreted
    and implemented by the [DOL]."            Id.3      Congress then permanently
    3
    The plaintiffs assert that the District Court incorrectly
    "suggested that the federal government has [since] 'abandoned'"
    the formula establishing an au pair's minimum wage requirements
    set out in the 1997 regulations, which was a formula based on the
    federal minimum wage multiplied by a presumed 45-hour work week
    minus a   deduction for the costs of room and board.     But, the
    District Court merely accurately described how the text of the
    regulations had changed over time.
    - 13 -
    authorized the Au Pair Program.          See An Act to Provide Permanent
    Authority for the Administration of Au Pair Programs, Pub. L. No.
    105-48, 
    111 Stat. 1165
     (1997).
    The DOS now promulgates the au pair exchange program
    regulations.        Compare 
    id.
     with 
    22 C.F.R. § 62.31
    (j)(1).               The
    current DOS version of the regulations describes the "objectives"
    of this type of exchange visitor program as "afford[ing]" to
    "foreign nationals" the "opportunity to live with an American host
    family and participate directly in the home life of the host
    family" while providing "up to" 45 hours a week of childcare
    services to the host family and also pursuing a post-secondary
    education. 
    22 C.F.R. § 62.31
    (a)-(b). The current version of these
    regulations also includes a "Wages and hours" provision that
    mirrors the one in the 1997 version of the USIA's au pair exchange
    program    regulations.     That     provision   states:    "Sponsors     shall
    require that au pair participants [a]re compensated at a weekly
    rate based upon 45 hours of child care services per week and paid
    in conformance with the requirements of the [FLSA] as interpreted
    and implemented by the [DOL.]"         
    Id.
     § 62.31(j)(1).
    The current version of the regulations that govern au
    pair exchange programs authorizes the DOS to designate a "bona
    fide program[]" of this type as an "exchange visitor program" if
    it "satisf[ies]" the specified "objectives" and if the "sponsor"
    meets     certain    "eligibility"     requirements,   as     well   as     the
    - 14 -
    regulations' "Wages and hours" requirements.          Id. § 62.31(b)-(c),
    (j).     Sponsors that fail to meet those requirements or that fail
    to "[e]nforce and monitor host family's compliance with the stipend
    and hours requirements" may face "immediate program revocation
    procedures."     Id. § 62.31(n).     The DOS au pair exchange program
    regulations do not provide that an au pair exchange program
    participant may enforce against a sponsor -- let alone against a
    host family -- the only sanctions that the regulations specify.
    See generally id. § 62.31.
    3.
    The au pair exchange program regulations, through their
    "Wages     and   hours"   provision,        cross-reference   the   FLSA's
    "requirements."    
    22 C.F.R. § 62.31
    (j)(1).        We thus briefly review
    the obligations that the FLSA and the DOL's regulations that
    implement the FLSA impose on the employers of domestic workers, as
    those "requirements" serve as the reference point under the Au
    Pair Program for calculating the weekly compensation that sponsors
    must require that au pair participants receive.
    Under the FLSA, "employer[s] shall pay to each of [their]
    employees" a minimum hourly wage that is currently set at $7.25
    per hour.    
    29 U.S.C. § 206
    (a).    In 1974, Congress amended the FLSA
    so that it would apply to domestic workers and their employers.
    Fair Labor Standards Amendments of 1974, Pub. L. No. 93-259, 
    88 Stat. 55
     (codified as amended in scattered sections of 29 U.S.C.).
    - 15 -
    This amendment imposed a new requirement on employers of domestic
    workers to pay the federally mandated minimum wage.             
    Id.
        However,
    the amendments exempt live-in domestic workers from the provisions
    that   require    employers    pay   to    employees    time-and-a-half      for
    overtime.    See 
    29 U.S.C. § 213
    (b)(21).
    In   implementing    these     amendments     in   1975,   the   DOL
    promulgated      regulations    that      imposed   certain     recordkeeping
    obligations on employers of domestic workers and that permitted
    those employers to deduct the costs of the domestic worker's room
    and board from the domestic worker's pay.              Extension to Domestic
    Service Employees, 
    40 Fed. Reg. 7404
     (Feb. 20, 1975) (to be
    codified at 29 C.F.R. pt. 552).           Employers were to calculate such
    deductions either by using a fixed credit that totaled $36 per
    week or by deducting their actual costs for room and board,
    provided that the employers kept records to support those itemized
    deductions.      Id. at 7406.        The current version of these DOL
    regulations      permit   employers       of   domestic    workers     to    take
    deductions either by using a fixed credit amount that is tied to
    a percentage of the federal minimum wage or by deducting their
    actual, itemized costs, if the itemized deductions are supported
    by adequate records.      
    29 C.F.R. § 552.100
    (c)-(d).
    The FLSA contains a savings clause.           
    29 U.S.C. § 218
    (a).
    It provides that "[n]o provision of this chapter or of any order
    thereunder shall excuse noncompliance with any Federal or State
    - 16 -
    law or municipal ordinance establishing a minimum wage higher than
    the minimum wage established under this chapter."               
    Id.
    B.
    We now turn to the state law measures.             Like the federal
    ones, they consist of a mix of statutory and regulatory provisions.
    1.
    We start with the Massachusetts Fair Wage Law.                     It
    requires that all "employer[s]" pay a minimum wage set, as of
    January 1, 2019, at $12 per hour, except in certain circumstances
    that are not relevant here.            
    Mass. Gen. Laws ch. 151, § 1
    .           A
    different section of the Massachusetts Fair Wage Law requires that
    "employer[s]" pay "employee[s]" at a rate of time-and-a-half for
    all hours that the "employee[s]" work in a week beyond 40 hours.
    
    Id.
     § 1A.
    2.
    We next describe the Massachusetts Domestic Workers Bill
    of Rights Act ("DWBORA"). Enacted in 2014, it sets forth workplace
    protections    --   including       concerning   wages    and    hours   --   for
    "domestic workers."         2014 Mass. Acts ch. 148, § 3 (codified at
    
    Mass. Gen. Laws ch. 149, §§ 190-191
    ).        The    DWBORA   defines
    "domestic worker[s]" to include, in relevant part, "individual[s]
    or employee[s]" providing "nanny services" and "other household
    services for members of households . . . in private homes."               
    Mass. Gen. Laws ch. 149, § 190
    (a).
    - 17 -
    The   DWBORA   also   authorizes   the   Attorney    General   to
    promulgate regulations to implement its provisions, which the
    Attorney General has done.         
    Id.
     § 190(o); see 
    940 Mass. Code Regs. 32.00
    -.06.    We now describe the Attorney General regulations that
    are relevant to this appeal.
    Whenever a domestic worker clocks more than 40 hours of
    "working time" in a given week, the Attorney General's regulations
    require that he or she be "compensated at the overtime rate for
    all hours worked over 40 per week pursuant to [the Massachusetts
    Fair Wage Law]."       
    940 Mass. Code Regs. 32.03
    (3).             One of the
    regulations that implements the DWBORA defines "working time" as
    "[c]ompensable time that includes all time during which a domestic
    worker is required to be on the employer's premises or to be on
    duty."    Id. 32.02.   This definition also defines "working time" to
    include    "meal     periods,      rest   periods,    and   sleep    periods
    unless . . . a domestic worker is free to leave the employer's
    premises and use the time for the domestic worker's sole use and
    benefit and is completely relieved of all work-related duties."
    Id.   The regulation provides, however, that employers and domestic
    workers may enter into an advance written agreement that excludes
    "meal periods, rest periods, and sleep periods."            Id.
    Other regulations that implement the DWBORA concern the
    deductions that an employer may take from a domestic worker's wages
    for the costs of that domestic worker's food and lodging.              These
    - 18 -
    regulations limit these deductions to $1.25 for breakfast, $2.25
    for lunch, $2.25 for dinner, and to $35 per week for a single-
    occupancy room.       Id. 32.03(5)(b)-(c).        These deductions must be
    agreed to, in advance and in writing, by the domestic worker.
    Id. 32.03(5)(a).
    Finally,    the     regulations     that    implement   the   DWBORA
    impose recordkeeping requirements on the employers of domestic
    workers.    For example, the employers of domestic workers must keep
    and retain for a period of three years records concerning the
    domestic workers' wages and hours, the rate of their pay, the costs
    for their meals and lodging, and various workplace policies, such
    as benefits afforded, required notice of termination, and job
    responsibilities.        See     id. 32.04(2)-(3).         In   addition,    the
    employers of domestic workers must keep time sheets that reflect
    the compensable working time of the domestic worker for each day
    over   a   two-week    period    and    provide   the    domestic   worker   an
    opportunity to review and contest that accounting of hours.                  Id.
    32.04(4).
    3.
    The parties agree that the Attorney General considers au
    pair exchange program participants to be "domestic workers" and
    their host families to be "employers" within the meaning of the
    DWBORA.     The parties also agree that au pair participants are
    "employees" within the meaning of the Massachusetts Fair Wage Law.
    - 19 -
    II.
    The parties ask us to resolve two preliminary issues.
    They concern, respectively, the scope and the nature of the
    plaintiffs' preemption claims.
    The     "scope"     issue    arises      because,     although    the
    complaint's prayer for relief does not mention the Massachusetts
    Fair    Wage    Law,    the    plaintiffs     contend     that    their   preemption
    claims -- and thus their request for injunctive and declaratory
    relief -- encompass that law.                 The Attorney General contends,
    however, that the plaintiffs' preemption challenge is confined to
    the DWBORA and its implementing regulations, because the prayer
    for relief set forth in the plaintiffs' complaint refers only to
    those specific state law measures.                 Our review of this issue is de
    novo.   Carter v. Ford Motor Co., 
    561 F.3d 562
    , 565 (6th Cir. 2009).
    "A plaintiff's failure to seek a remedy in its complaint
    does not necessarily forgo that remedy."                   Town of Portsmouth v.
    Lewis, 
    813 F.3d 54
    , 61 (1st Cir. 2016).                  Thus, "a district court
    need not dismiss a cause of action upon which relief is plausible,
    even if that relief was not sought in the complaint."                     
    Id.
    The plaintiffs' complaint expressly alleges that the
    requirement          that     au   pair     participants         comply   with   the
    Massachusetts minimum wage, as prescribed by the Massachusetts
    Fair Wage Law, "contradicts existing [DOS] requirements" about
    "the federal minimum wage, which [the DOS] has chosen to use in
    - 20 -
    calculating the amount of the [au pair's] weekly stipend."              In
    addition,   the   District   Court's   opinion   addressed    whether   the
    Massachusetts Fair Wage Law was preempted insofar as it applied to
    au pair participants.     In fact, at each stage of this litigation,
    the Attorney General has argued that the Massachusetts Fair Wage
    Law's minimum wage requirement applies to au pair participants.
    Thus, there is no unfair surprise to the Attorney General in our
    consideration     of   whether   the   DOS    regulations    preempt    the
    Massachusetts minimum wage that the Massachusetts Fair Wage Law
    generally establishes for those who qualify as "domestic workers"
    under the DWBORA, insofar as that minimum wage requirement applies
    to the host families as the employers of au pair participants.
    See Lewis, 813 F.3d at 61 (explaining that complaints should
    generally be read broadly, except when it would be likely to
    prejudice a defendant).
    The "nature" issue arises because the plaintiffs contend
    that they need only establish that the challenged state "laws are
    invalid" as applied to the "Au Pair Program."               The plaintiffs
    argue that they need not show that "no set of circumstances exists"
    under which the challenged laws would be valid in any application.
    Even though the plaintiffs' preemption challenges are facial in
    nature, we agree with the plaintiffs.        See John Doe No. 1 v. Reed,
    
    561 U.S. 186
    , 194 (2010) (explaining that the particular label of
    the claim -- facial versus as applied -- "is not what matters" and
    - 21 -
    that "[t]he important point" is that the plaintiffs must "satisfy
    our standards for a facial challenge to the extent of [the] reach"
    of their claims).   In fact, we do not understand the defendants to
    contend otherwise or the District Court to have ruled otherwise.4
    III.
    We now turn to the heart of the dispute: are the state
    law measures at issue -- in whole or in part -- preempted, insofar
    as they protect au pair participants by imposing obligations on
    their host families as their employers that may be enforced against
    those host families?5   The Supremacy Clause provides that federal
    4 This case does arise in the pre-enforcement context, but
    the preemption claims involve "purely legal questions, where the
    matter can be resolved solely on the basis of the state and federal
    statutes at issue," Labor Relations Div. of Constr. Indus. of
    Mass., Inc. v. Healey, 
    844 F.3d 318
    , 327 (1st Cir. 2016)(quoting
    Wis. Cent., Ltd. v. Shannon, 
    539 F.3d 751
    , 759 (7th Cir. 2008)).
    There also is no question that Massachusetts intends to enforce
    the challenged state law measures to protect au pair participants
    insofar as they are denied the protection that those measures
    afford their employers. See 
    id.
    5 The plaintiffs allege in their complaint that, in the spring
    of 2015, the Office of the Attorney General of Massachusetts
    ("OAG") "suggested that Sponsors should be considered non-exempt
    'placement agencies' -- and therefore potentially also employers
    -- under the [DWBORA] and the MA regulations.          The meeting
    terminated without clarity as to whether the MA OAG ultimately
    would, or would not, interpret the MA Act as applying to [Cultural
    Care]." The plaintiffs asked the District Court to conclude that
    the state law measures were preempted and could not be enforced
    against Cultural Care or Cultural Care's host families.       In so
    doing, the plaintiffs did not develop an argument in support of
    those preemption claims that depends on the state law measures
    being enforced against Cultural Care, as a sponsor, and instead
    focused their argument on why the state law measures were preempted
    - 22 -
    law "shall be the supreme Law of the Land . . . any Thing in the
    Constitution or Laws of any State to the Contrary notwithstanding."
    U.S. Const. art. VI, cl. 2.   This Clause gives Congress "the power
    to preempt state law," which Congress may exercise either expressly
    or impliedly.   Arizona v. United States, 
    567 U.S. 387
    , 399 (2012).
    A federal agency, however, also may preempt state law through its
    regulations, and a federal agency, too, may do so either expressly
    insofar as they could be enforced against the host families as
    employers of au pair participants. The District Court in rejecting
    the plaintiffs' preemption claims did not address, specifically,
    whether the DWBORA and its regulations -- or the state's minimum
    wage -- could be enforced against sponsors and not just the host
    families themselves.
    On appeal, the plaintiffs refer to the "Au Pair Program"
    but, once again, do not develop an argument for preemption that
    depends on the application of the state law measures to sponsors
    rather than to host families. Instead, in their briefing to us,
    the plaintiffs refer only to the obligations that the state law
    provisions at issue would impose on host families, in consequence
    of the childcare services that au pair participants provide to
    them through the Au Pair Program. We thus do not have the distinct
    question before us on appeal whether the DWBORA and its
    implementing regulations or the Fair Wage Law, as applied to
    sponsors in particular, are preempted by the federal regulations
    that govern sponsors of au pair exchange visitor programs. Nor is
    it clear that such a challenge to the enforceability of those
    measures against the sponsors would be ripe. See Labor Relations
    Div., 844 F.3d at 327 (finding a preemption challenge unripe where
    the nature of and legal basis for the state law enforcement action
    was uncertain).    We emphasize, though, that it is clear that
    Cultural Care, even though it is a sponsor rather than a host
    family, would be directly impacted by an application of the
    relevant state law provisions to host families, in light of
    Cultural Care's allegations about the impact that such application
    to host families would have on Cultural Care's ability to find
    host families with which to place au pair participants and the
    host family plaintiffs' allegations about their intention to serve
    as host families in the future.
    - 23 -
    or impliedly.      See Fidelity Fed. Sav. & Loan Ass'n v. de la Cuesta,
    
    458 U.S. 141
    , 153 (1982).
    The plaintiffs assert only implied preemption.                    There
    are two types -- field preemption and conflict preemption, which
    itself     comes     in   two      varieties:    obstacle        preemption    and
    impossibility preemption.           We begin with the plaintiffs' field
    preemption claim.         We then consider their conflict preemption
    claims, which concern only obstacle preemption.
    The burden to prove preemption is on the plaintiffs.
    See United States v. Lahey Clinic Hosp., Inc., 
    399 F.3d 1
    , 9 (1st
    Cir. 2005).    That is so even if the presumption against preemption
    that often applies to implied preemption claims does not apply
    here.    Lusnak v. Bank of Am., N.A., 
    883 F.3d 1185
    , 1191 (9th Cir.),
    cert. denied, 
    139 S. Ct. 567
     (2018).
    A.
    States    may    not    regulate    "conduct    in    a   field   that
    Congress, acting within its proper authority, has determined must
    be regulated by its exclusive governance."             Arizona, 
    567 U.S. at
    399 (citing Gade v. Nat'l Solid Waste Mgmt. Ass'n, 
    505 U.S. 88
    ,
    115     (1992)(Souter,      J.   dissenting).       Thus,    unlike     conflict
    preemption, field preemption ousts state law measures even if no
    evidence shows that they would conflict with the federal regulatory
    scheme either by frustrating its purposes and objectives, see Hines
    v. Davidowitz, 
    312 U.S. 52
    , 67 (1941), or by imposing obligations
    - 24 -
    that it would be impossible for the regulated party to comply with
    and also comply with the obligations that the federal regulatory
    scheme imposes, see Wyeth v. Levine, 
    555 U.S. 555
    , 589-90 (2009).
    The federal government's intent to preempt a field instead "can be
    inferred   from   [1]    a    framework      of    regulation     'so     pervasive
    . . . that'" it leaves "'no room for the States to supplement it'
    or [2] where there is a 'federal interest . . . so dominant that
    the federal system will be assumed to preclude enforcement of state
    laws on the same subject.'"              Arizona, 
    567 U.S. at 399
     (quoting
    Rice v. Santa Fe Elevator Corp., 
    331 U.S. 218
    , 230 (1947)).
    The    plaintiffs        contend       that    the     detailed       and
    comprehensive     nature     of    the    DOS     au   pair    exchange     program
    regulations   warrants       the   inference      that   the    DOS   intended   to
    exclusively govern a field of state regulation that encompasses
    the Massachusetts wage and hour measures, insofar as these measures
    may be enforced to protect the rights of au pair participants
    against their host families as their employers.                   The plaintiffs
    further contend that the dominance of the federal interests that
    the Au Pair Program implicates -- namely, the federal foreign
    affairs interest in regulating immigration and the federal foreign
    - 25 -
    affairs interest in managing foreign relations -- supports this
    same inference.6
    We review de novo the District Court's finding that there
    is no field preemption.    See Bower v. Egyptair Airlines Co., 
    731 F.3d 85
    , 92 (1st Cir. 2013).   We conclude that the District Court
    did not err in rejecting the plaintiffs' field preemption claim.
    1.
    In De Canas v. Bica, the United States Supreme Court
    considered a claim that "Congress, in enacting the [Immigration
    and Nationality Act ("INA")], intended to oust state authority to
    regulate" the employment of undocumented aliens "in a manner
    consistent with pertinent federal laws" due to the comprehensive
    and detailed nature of that federal statute. 
    424 U.S. 351
    , 357
    (1976).   The Court applied the presumption against preemption, see
    
    id. at 360-61
    , notwithstanding that the INA represented an exercise
    6 The plaintiffs also make a textual argument for finding
    field preemption based on the DOS "Exchange Visitor Program"
    regulations as a whole, which specifically require sponsors of
    certain other types of exchange visitor programs -- but not of au
    pair exchange programs -- to ensure that those who employ
    participants in those programs comply with state wage and hour
    laws.   The plaintiffs contend that we thus must infer -- by
    negative implication -- that the DOS did intend to preempt a field
    that would encompass state wage and hour laws that protect au pair
    participants. As the plaintiffs make this same argument in a more
    developed fashion in support of their claim of obstacle preemption,
    see Crosby v. Nat'l Foreign Trade Council, 
    530 U.S. 363
    , 372 n.6
    (2000) ("[w]e recognize, of course, that the categories of
    preemption are not "rigidly distinct"), we explain our reasons for
    rejecting the argument in that portion of our opinion, see infra
    Section III.B.2.
    - 26 -
    of   the   federal           government's    power    over   immigration     and   thus
    implicated the federal government's power over foreign affairs,
    see id. at 353.
    De Canas explained that the Court had "never held that
    every state enactment which in any way deals with aliens is a
    regulation of immigration and thus per se pre-empted by this
    constitutional power, whether latent or exercised."                     Id. at 355.
    De Canas added that the state laws at issue were not deciding "who
    should     or    should        not   be   admitted    into   the   country   and    the
    conditions under which a legal entrant may remain," as they merely
    concerned the power to employ undocumented aliens already in the
    country.        Id.
    The Court also explained that the state law measures --
    which regulated employment -- concerned a quintessentially local
    area of regulation.               See id. at 356-57.         This fact, the Court
    determined,           also     counseled    against    inferring     that    Congress
    intended to preempt the relevant field through the INA.                      Id.
    With the presumption against preemption in place, the
    Court then held that "[t]he comprehensiveness" of the INA, "without
    more[,]" was not sufficient to establish the "clear and manifest"
    congressional intent to oust state law that is required to overcome
    the presumption against preemption. Id. at 357, 359. Accordingly,
    the Court rejected the claim of field preemption, id., concluding
    that the "nature and complexity" of the federal subject matter
    - 27 -
    made the "detailed statutory scheme . . . likely and appropriate,
    completely apart from any questions of pre-emptive intent," id. at
    359-60 (quoting New York Dep't of Social Servs. v. Dublino, 
    413 U.S. 405
    , 415 (1973)).
    The   plaintiffs     do    not   dispute      that   the   presumption
    against preemption that De Canas applied would be especially
    difficult to overcome here.             The details of the federal program in
    this case are set forth in federal regulations, not a federal
    statute.    See Hillsborough Cty. v. Automated Med. Labs., Inc., 
    471 U.S. 707
    ,    717-18     (1985)    (justifying        a    reluctance    to    infer
    preemptive intent from the comprehensiveness of regulations based
    in part on the "variety of means, including regulations, preambles,
    interpretive statements, and responses to comments" through which
    an agency can "make their intentions clear if they intend for their
    regulations to be exclusive").
    In fact, we do not understand the plaintiffs to argue
    that, insofar as the presumption against preemption does apply,
    their field preemption claim can succeed.                  The plaintiffs contend,
    however, that the presumption against preemption on which De Canas
    relied does not apply.
    The plaintiffs rely on Buckman Co. v. Plaintiffs' Legal
    Committee, 
    531 U.S. 341
    , 347 (2001), for that assertion.                        They
    contend    that     the   assertedly      preemptive       federal   measures   here
    operate in fields that are "inherently federal in character," 
    id.,
    - 28 -
    foreign relations and immigration, and thus that, under Buckman,
    the presumption against field preemption that the Supreme Court
    applied in De Canas does not apply.           But, Buckman -- which
    concerned conflict, not field preemption, 
    id.
     at 348 -- explained
    that the presumption against preemption did not apply there because
    the "federal enactments [were] a critical element" in the state
    law claim in that case.     See 
    id. at 353
    .     The state employment
    laws that the plaintiffs seek to preempt here, however, are
    generally applicable to all domestic workers.     Thus, they are not
    predicated on the existence of the federal au pair exchange program
    regulations.   See 
    Mass. Gen. Laws ch. 149, §§ 190-191
    ; 
    940 Mass. Code Regs. 32.00
     et seq.7
    7 The DOS, we note, in its amicus filing, invokes Wachovia
    Bank, N.A. v. Burke, 
    414 F.3d 305
    , 314 (2d Cir. 2005), to argue
    that there is no presumption against preemption if federal
    authority has occupied the field "for an extended period of time."
    But, Wachovia, which concerned the preemptive effect of the federal
    regulation of national banks, did not purport to hold that the
    presumption against preemption has no application to a federal
    regulatory scheme merely because it implicates, in some manner, a
    "field[] of regulation that ha[s] been substantially occupied by
    federal authority for an extended period of time." 
    414 F.3d at
    314 (citing Flagg v. Yonkers Sav. & Loan Ass'n, 
    396 F.3d 178
    , 183
    (2d Cir. 2005)). Nor, in light of De Canas, do we see how Wachovia
    could be read to stand for such a proposition. We note, too, that
    Wachovia addresses the application of the presumption against
    preemption only in connection with the question of whether Congress
    intended to authorize the federal agency charged with regulating
    national banks to preempt state laws that purported to regulate
    such banks and not with respect to the question of whether the
    federal agency itself had intended to do so. There was no dispute
    in that case -- as there plainly is here -- concerning the intent
    of the federal agency with respect to preemption.
    - 29 -
    Even if we were to agree that the presumption against
    field preemption does not apply, the plaintiffs would still bear
    the burden of proving that the Au Pair Program does preempt the
    relevant field. And, as we will next explain, we find unpersuasive
    the plaintiffs' arguments as to why there is affirmative evidence
    of a field preemptive intent here.
    2.
    The plaintiffs emphasize that the DOS regulations that
    establish the Au Pair Program are detailed and comprehensive. But,
    we do not see why, especially in light of the reasoning in De
    Canas, that fact alone justifies the inference that the federal
    government intended the Au Pair Program to preempt a field that
    would encompass the state law measures at issue.     As in De Canas,
    we conclude that here, too, a "detailed [federal] scheme [is]. . .
    likely and appropriate, completely apart from any questions of
    pre-emptive intent."   
    424 U.S. at 360
     (quoting Dublino, 
    413 U.S. at 415
    ).
    The regulations set forth detailed requirements that the
    DOS may enforce through sanctions.      The regulations are directed
    at the sponsors, however, and the sanctions that the DOS may
    enforce apply to them, not the host families themselves.         The
    sanctions also merely limit or end -- save for exceptions not
    relevant here -- the ability of the sponsors to continue to conduct
    DOS-approved au pair exchange programs.     Thus, the DOS's decision
    - 30 -
    to promulgate detailed and comprehensive regulations, given that
    they govern and sanction sponsors, does not support an inference
    that the DOS thereby intended to oust state employment laws that
    define, as part of a generally applicable regulatory scheme, the
    rights and duties of au pair participants and host families with
    respect to each other in their employment relationship.          For, De
    Canas makes clear, the mere fact that a state law implicates the
    interests of persons who are the subject of federal regulation,
    even with respect to immigration, does not alone provide a basis
    for inferring that the federal regulatory scheme was intended to
    preempt a field that encompasses such a state law, at least when
    it concerns a matter of such quintessentially local concern as
    employment.   Cf.   id.   at   360-61,    (explaining   that   federalism
    concerns "require[] us not to find withdrawal from the States of
    power to regulate where the activity regulated was a merely
    peripheral concern of the (federal regulation)" (quoting San Diego
    Unions v. Garmon, 
    359 U.S. 236
    , 243 (1959)) (second alteration in
    the original)).8
    8 In support of this aspect of their field preemption
    challenge, the plaintiffs also invoke the conclusion in ASSE Int'l,
    Inc. v. Kerry, 
    803 F.3d 1059
    , 1070–71 (9th Cir. 2015), that the
    Exchange    Visitor    Program    regulations,    generally,    are
    "comprehensive." That case does not address, however, the question
    of preemption.     Rather, it concerns only whether there was
    sufficient law to apply to permit review under the Administrative
    Procedure Act, 
    5 U.S.C. §§ 551
    , 706, of the DOS's compliance with
    those regulations. Furthermore, the Exchange Visitor Program
    - 31 -
    The plaintiffs also point to the fact that the Au Pair
    Program implicates the federal government's power over foreign
    affairs, both with respect to immigration and foreign relations.
    The plaintiffs contend that this feature of the Au Pair Program
    also requires us to presume an intent to preempt the relevant
    field.    But, we do not agree.
    Insofar as the Au Pair Program implicates the federal
    power over immigration, the Court's ruling in De Canas stands in
    the way of the plaintiffs' contention that, in consequence, we
    must presume an intent to preempt the relevant field.            The Court
    made clear in De Canas that the fact that a state law applies to
    aliens does not alone justify a presumption that the federal
    government intended for the INA to preempt such a law.          See id. at
    355.     Moreover, the state law employment measures at issue in De
    Canas applied only if the employees were undocumented aliens, see
    id. at 356, and thus, in that respect, more directly implicated
    the    federal   power   to   regulate   immigration   (and   thus   foreign
    affairs) than do the generally applicable state law wage and hour
    measures that are at issue here.            In addition, these state law
    regulations at issue in ASSE Int'l did not include those governing
    au pair participants. Moreover, consistent with our analysis, the
    Ninth Circuit pointedly observed there that "[f]or program
    sponsors, the regulations have the force of law, and there are
    real consequences for failing to abide by them." Id. at 1070-71
    (emphasis added).
    - 32 -
    measures do not purport -- as the ones at issue in De Canas did,
    id. at 364, -- to preclude the foreign nationals affected by them
    from being employed.            They merely establish the wage and hour
    rights      that   the    foreign   nationals        affected   by    the    federal
    regulatory scheme enjoy if they are employed.
    The plaintiffs separately contend that, because the Au
    Pair Program implicates the distinct federal interest in promoting
    international       cultural      exchange,     it    implicates      "a    'federal
    interest . . . so dominant that the federal system will be assumed
    to preclude enforcement of state laws on the same subject.'"
    Arizona, 
    567 U.S. at 399
     (quoting Rice, 
    331 U.S. at 230
    ).                    If the
    states were allowed "to apply their own laws to the Au Pair
    Program," the plaintiffs assert, then those states' laws "would
    inevitably interfere with the federal government's exclusive power
    to   determine     what      regulations    will     best   achieve   its   foreign
    relations goals."
    But, the plaintiffs do not account for the disjuncture
    between the sponsor-based focus of the DOS regulations and the
    employment-based focus of the state law measures.                     Nor is there
    precedent that indicates that a federal program that represents an
    exercise of the federal power to manage foreign relations -- even
    if   only    through     a   program   to   promote     international       cultural
    exchange -- must be presumed, for that reason alone, to preempt a
    state law that merely implicates that power.                  See Am. Ins. Ass'n
    - 33 -
    v. Garamendi, 
    539 U.S. 396
    , 419 n.11 (2003) (explaining that, where
    a state is "act[ing] within . . . its 'traditional competence,'"
    it might well make sense to require some evidence of an actual
    conflict between the federal and state laws in order to find
    preemption    on       an   implicit    basis     even    when    the     federal   law
    implicates    the      federal   interest        in   foreign     affairs     (quoting
    Zschernig    v.    Miller,     
    389 U.S. 429
    ,    459      (1968)    (Harlan,   J.,
    concurring))).9
    This case also is not one in which it would make sense
    to adopt such a pro-field-preemption presumption.                       The plaintiffs
    themselves emphasize that Congress intended for the Au Pair Program
    to "promote international cooperation" and to "assist in the
    development       of   friendly,     sympathetic,        and    peaceful     relations
    between the United States and the other countries of the world."
    
    22 U.S.C. § 2451
    .           It is hardly evident that a federal foreign
    affairs interest in creating a "friendly" and "cooperative" spirit
    with other nations is advanced by a program of cultural exchange
    that, by design, would authorize foreign nationals to be paid less
    9 The plaintiffs also point out that, although the au pair
    regulations require that au pair participants be between the ages
    of 18 and 26, Massachusetts age discrimination laws "prohibit age
    discrimination against any person over the age of 40."      See 40
    Mass. Gen. Laws ch. 149, § 24A. But, the fact that the federal
    scheme might conflict with, and thus preempt, specific sections of
    Massachusetts law unrelated to a domestic worker's wage and hour
    rights provides no support for the assertion that the entire field
    of state wage and hour laws is preempted with respect to their
    application to host families as employers of au pair participants.
    - 34 -
    than Americans performing similar work.                      We thus conclude, like
    the District Court, that the plaintiffs have failed to meet their
    burden to show that the federal government intended to preempt a
    field that would encompass the state law measures that they
    challenge.
    B.
    We now consider the plaintiffs' conflict preemption
    claims, which concern only obstacle preemption.10 As we have noted,
    the   burden    to   establish      this    form       of    preemption    is   on   the
    plaintiffs, whether or not the presumption against preemption
    applies.
    The notion that underlies obstacle preemption is that
    the   federal    government      would      want       a    federal   measure   to   be
    preemptive of any state law that "stands as an obstacle to the
    accomplishment and execution of the full purposes and objectives"
    of that federal measure,         Hines, 
    312 U.S. at 67
    ; see also Geier v.
    Am.   Honda    Motor   Co.,   
    529 U.S. 861
    ,       873   (2000).   Thus,     the
    plaintiffs do not, as they did in arguing for field preemption,
    ask us to infer an intent on the part of the federal government to
    10The plaintiffs make no argument concerning the other
    variant of conflict preemption -- known as impossibility
    preemption -- because they do not dispute that it is possible for
    sponsors, au pair participants, and host families alike to comply
    with each of the state law measures at issue while also complying
    with each of the federal ones.
    - 35 -
    oust a whole field of state regulation merely from the detailed
    and   comprehensive   nature   of   the   au   pair   exchange    program
    regulations.   Nor do they ask us to infer such an intent from the
    fact that the Au Pair Program implicates the federal foreign
    affairs power over immigration or foreign relations.             Instead,
    they ask us to draw the requisite inference of an intent to oust
    the state wage and hour laws at issue from what they contend are
    the specific purposes and objectives that underlie that federal
    program.
    The plaintiffs contend in that regard as follows.          The
    plaintiffs argue that, to accomplish the underlying objective of
    promoting international cultural exchange, Congress and the DOS
    sought, in establishing the Au Pair Program, to: (1) encourage a
    diverse array of American families throughout the United States to
    host au pair participants, (2) encourage foreign nationals to seek
    out placements with host families in all parts of the country, and
    (3) ensure that the relationship between host families and au pair
    participants would be marked by true cultural exchange.              The
    plaintiffs contend that it follows from these asserted underlying
    purposes and objectives that we must infer (1) that the DOS
    intended to set a uniform, nationwide ceiling on the obligations
    that could be imposed by states on host families with respect to
    the wage and hour rights of au pair participants; (2) that, in
    service of this end, the federal government intended to establish
    - 36 -
    a   nationwide,    uniform    ceiling     on   the   recordkeeping     and
    administrative burdens that could be imposed on host families with
    respect to au pair participants who provide in-home childcare
    services to them; and (3) that the obligations set forth in the
    DOS au pair exchange program regulations on sponsors themselves
    constitute that ceiling.
    The plaintiffs then tie up their argument for finding
    obstacle preemption this way.      They contend that the enforcement
    of each of the challenged Massachusetts measures necessarily would
    frustrate the federal objective of establishing such a nationally
    uniform system of compensation.          The enforcement of each such
    measure,   they   argue,   necessarily    would   exceed   the   regulatory
    ceiling that the Au Pair Program established by imposing an
    independent and additional state obligation on host families not
    imposed by the Au Pair Program itself.11
    11In setting forth this contention, the plaintiffs go into
    considerable detail about the claimed burdensome impact of these
    Massachusetts measures on host family obligations with respect to
    compensation, recordkeeping, and administration.           But, we
    understand the plaintiffs to be pointing to these alleged burdens
    merely to provide support for the actual premise of their obstacle
    preemption claims: that the purpose of the DOS and Congress was to
    establish a nationally uniform compensation and hours ceiling --
    pegged in substantial part to the minimum requirements of the FLSA
    -- that would preempt the wage and hour rights that states might
    confer on the au pair participants themselves to enforce against
    their host families. See infra Section III.B.3.a.        We do not
    understand the plaintiffs to be making an argument that these
    particular state law measures may be deemed preemptive only because
    they are especially burdensome, such that other state wage and
    - 37 -
    We begin by reviewing the relevant precedents in this
    area and how they bear on the plaintiffs' argument that there
    should be no presumption against finding that the state law
    measures in this case would pose an obstacle to the accomplishment
    of the Au Pair Program's purposes and objectives.             We then explain
    why, reviewing the issue de novo, see Bower, 731 F.3d at 92, we
    conclude that the plaintiffs have not met their burden to establish
    obstacle    preemption    here,    even      if   the   presumption     against
    preemption does not apply.
    1.
    The plaintiffs contend, in essence, that the relevant
    DOS regulations set not only a federal regulatory floor on au pair
    participant wage and hour protections but also, implicitly, a
    federal    regulatory    ceiling    that     limits     the   wage    and   hour
    protections that states may provide to au pair participants.                  A
    similar floor-ceiling issue arises with some frequency in disputes
    over obstacle preemption.     It often does so, however, in settings
    that do not implicate immigration or foreign relations.                 It thus
    often   arises   in   settings     in    which    the   presumption     against
    preemption -- and thus a presumption against construing the federal
    hour measures that would impose less burdensome but still
    independent and additional obligations on host families would not
    be preempted.
    - 38 -
    regulatory floor also to be a ceiling on state regulation-- more
    clearly applies.
    Here,   however,   the    plaintiffs      contend    that   no   such
    presumption against preemption applies, given the nature of the
    federal   interests     implicated      by     the    Au   Pair   Program.    The
    plaintiffs rely on Boyle v. United Technologies Corp., which they
    contend holds that the evidence of "[t]he conflict with federal
    policy need not be as sharp" when the federal government is
    operating in a field of unique federal interest, such as the
    plaintiffs    contend   that    the    fields    of    foreign    relations   and
    immigration implicated by the Au Pair Program are.                
    487 U.S. 500
    ,
    507 (1988).     The plaintiffs further contend that, in the absence
    of such a presumption against preemption, we must conclude that
    the state law measures would frustrate the federal objective of
    establishing a nationally uniform compensation scheme for au pair
    participants.
    But, even if Boyle could be read to suggest that the
    evidence of the ceiling-setting intention here need not be clear,
    the plaintiffs still bear the burden of demonstrating that there
    is a conflict between the state law measures and the Au Pair
    Program by showing that the former would frustrate the purposes
    and objectives of the latter.            Moreover, the plaintiffs do not
    dispute that, to meet that burden, they must identify affirmative
    evidence that Congress or the DOS had a ceiling-setting -- and
    - 39 -
    thus obstacle-preemption-creating -- intent.                       See Arizona, 
    567 U.S. at 400, 414
     (describing the presumption against preemption in
    a case involving preemption based on federal immigration law and
    finding one provision "likely would survive preemption -- at least
    absent     some      showing    that     it   has       other   consequences      that
    are adverse to federal law and its objectives").
    As we will next explain, the plaintiffs' arguments about
    the   text      of    the     relevant     federal       statutes    and    the     DOS
    regulations, as        well     as   their    underlying        history, fails      to
    identify the needed affirmative evidence.                  Thus, we conclude that
    a finding       of     the     requisite ceiling-setting             intent       would
    necessarily rest on the kind of unfounded speculation about the
    federal government's implicit intentions that may not ground a
    finding    of     obstacle     preemption.        See    Chamber    of   Commerce   of
    U.S. v. Whiting, 
    563 U.S. 582
    , 607 (2011) (plurality opinion).12
    12We note that two relatively recent cases, Geier, 
    529 U.S. 861
    , and Williamson v. Mazda Motor of Am., Inc., 
    562 U.S. 323
     (2011),
    wholly apart from their apparent reliance on the presumption
    against preemption, are instructive in fleshing out the kind of
    inquiry that courts must undertake to determine whether a federal
    agency regulation that clearly sets a regulatory floor for private
    conduct should nonetheless be construed to have impliedly also set
    a federal regulatory ceiling for the regulation of that private
    conduct by the states.    In Geier, for example, the Court found
    that, in requiring automobile manufacturers to install passive
    restraints, such as airbags, in their vehicles, the United States
    Department of Transportation ("DOT") had deliberately provided the
    manufacturers with a range of choices to encourage technological
    development. Geier, 
    529 U.S. at 874-79
    . Thus, the Court found
    that the DOT had impliedly established not only a choice-
    - 40 -
    2.
    We have already explained why the federal statutory
    provisions that authorize the Au Pair Program do not, by terms,
    demonstrate that the federal government impliedly intended to
    establish a nationally uniform compensation scheme.              See supra
    Section III.A.2.    Nor do the plaintiffs develop an argument that
    those provisions themselves, independent of the DOS regulations
    that   implement   the   Au   Pair    Program,   show   that   the   federal
    government intended to establish the kind of ceiling that would
    create the conflict that would warrant a finding of obstacle
    restricting regulatory floor on the manufacturers, but also a
    choice-preserving regulatory ceiling on what states could mandate
    manufacturers must do with respect to installing passive
    restraints. Id. Therefore, the Court held, a state tort law that
    imposed a duty on the manufacturers to install a specific type of
    passive restraint was preempted because its enforcement would
    frustrate the implicit federal objective of preserving the choice
    of manufacturers to comply with the federal regulation by a means
    other than the installation of that type of passive restraint. Id.
    at 882.
    In Williamson, which concerned a related DOT regulation,
    however, the Court came to the opposite conclusion.          There,
    the DOT's seatbelt regulation once again left manufacturers with
    a choice -- this time as to what type of seatbelt to install.
    Moreover, as in Geier, the state law at issue "would restrict that
    choice" by requiring additional safety measures. Williamson, 
    562 U.S. at 332
    . But, Williamson ruled that, because the DOT, in the
    federal regulation at issue, was concerned only with safety and
    not   with providing   manufacturers    with   a   choice   as   to
    what seatbelt to install, the state law requirement under review
    was not preempted. 
    Id.
     Moreover, Williamson explained, although
    the state law requirement that was being challenged would impose
    costs on the manufacturers above those that they would incur by
    complying with the federal regulation's floor, that fact alone
    provided no basis for finding a preemption-creating conflict
    between state and federal law. 
    Id. at 335
    .
    - 41 -
    preemption.        We thus follow the parties in focusing our attention
    on the DOS regulations that define the parameters of the Au Pair
    Program.      See CSX Transp., Inc. v. Easterwood, 
    507 U.S. 658
    , 664
    (1993).
    To    show    the    requisite    ceiling-setting        intent,   the
    plaintiffs focus chiefly on the provision of the au pair exchange
    program regulations that is entitled "Wages and hours." 
    22 C.F.R. § 62.31
    (j).        The provision states: "Sponsors shall require that au
    pair participants: (1) Are compensated at a weekly rate based upon
    45 hours of child care services per week and paid in conformance
    with the requirements of the [FLSA] as interpreted and implemented
    by the [DOL]."        
    Id.
         That provision further states, with respect
    to hours, that sponsors "shall require" that "au pair participants
    . . . do not provide more than 10 hours of child care per day, or
    more   than    45    hours    of    child   care    in    any   one    week."    
    Id.
    §62.31(j)(2).
    The plaintiffs emphasize that the provision sets the
    amount of compensation that sponsors shall require that au pair
    participants        receive    each   week.        It    sets   that   amount,   the
    plaintiffs note, on the assumption that au pair participants will
    provide the full 45 hours of childcare services a week that the Au
    Pair Program permits them to provide, regardless of whether the au
    pair participants provide it.               The plaintiffs contend that the
    provision in this way reveals that the DOS intended to establish
    - 42 -
    a   compensation   system     that   is    not    intended   to    pay   au   pair
    participants for the actual number of hours that they work.                   It is
    proper to infer, the plaintiffs thus argue, that the DOS did not
    intend for au pair participants to be able to require their host
    families to pay them the minimum wage that a state might require
    for each actual hour of work, if the resulting wage for the week
    would exceed the weekly compensation amount set forth in the DOS
    regulations themselves for 45 hours of such work.                   Rather, the
    plaintiffs    assert,   the   text    of   this    provision      shows,   albeit
    implicitly, that the DOS intended to set an independent, nationally
    uniform compensation scheme that would preempt a more generous one
    that a state might establish, even if the state law scheme took
    the form of a generally applicable wage and hour law.
    But, the text of this provision imposes the obligation
    to require that au pair participants receive a certain amount of
    weekly compensation only on the sponsors.            No obligation, enforced
    by the DOS, is imposed on the host families themselves.                        The
    obligation that DOS may enforce against the sponsors is defined,
    moreover, in terms that make it hard to draw the ceiling-setting
    inference that the plaintiffs ask us to make.
    An au pair participant is clearly paid "in conformance
    with" the FLSA minimum wage for a domestic worker who provides 45
    hours a week in childcare services, so long as that participant
    receives not less than that minimum amount of weekly compensation.
    - 43 -
    Indeed, the plaintiffs concede that this text does not forbid au
    pair participants from being paid more.      Thus, the plaintiffs
    acknowledge, for example, that, in accord with this provision, a
    host family may voluntarily pay an au pair participant more than
    the minimum wage required by the FLSA for that amount of work
    without creating any conflict with this provision. But, if a
    sponsor would meet its obligation -- which is the obligation that
    the regulations empower the DOS to enforce -- in the event a host
    family chooses to be that generous, then we fail to see what in
    the provision's text indicates that a host family may not be
    required to pay that higher wage in order to comply with a state
    wage and hour law.   After all, a sponsor would be no less able to
    fulfill its obligation to ensure that au pair participants are
    paid "in conformance with" the FLSA -- given that it merely sets
    a non-preemptive floor -- in that circumstance.13
    13We note, too, that the current "Wage and hour" provision
    replaced the "Stipend and hours" provisions of the 1994 and 1995
    regulations.   See supra Section I.A.2.       Each of those prior
    versions   of   the   au  pair    exchange   program   regulations,
    respectively,   obliged  sponsors    to   require   that  au   pair
    participants "are compensated not less than" $155 or $115. 59 Fed.
    Reg. at 64,300; 60 Fed. Reg. at 8553 (emphasis added). That "not
    less   than"    formulation    sounds    in   floor-setting,    not
    ceiling-setting, terms. 59 Fed. Reg. at 64,300; 60 Fed. Reg. at
    8553. Yet, the plaintiffs do not contend that the agency later
    meant to shift course when it changed the language to oblige
    sponsors   to  require   that   au   pair   participants   received
    compensation pegged to a calculation based on "conformance with"
    - 44 -
    The au pair exchange program regulations do contain a
    section that purports to describe the "objectives" of the Au Pair
    Program. See 
    22 C.F.R. § 62.31
    (a)-(b). But, this provision does
    not refer to a federal governmental interest in setting a uniform
    national standard for either au pair participant wages or for host
    family recordkeeping requirements.      
    Id.
       Nor do the plaintiffs
    contend otherwise, as they do not argue that the "objectives"
    provision itself supports their position about what the implicit
    objectives of the Au Pair Program are.
    The "objectives" section does state that "[a]u pair
    participants provide up to forty-five hours of child care services
    per week and pursue not less than six semester hours of academic
    credit . . . during their year of program participation."     
    Id.
     §
    62.31(a).    But, neither the "objectives" section nor any other
    provision of the DOS regulations refers -- at least in any express
    way -- to an agency interest in capping, based on the FLSA minimum
    wage, the costs of a host family that chooses to have an au pair
    participant provide the full amount of childcare services that the
    Au Pair Program allows.    Nor do the Au Pair Program regulations
    reference state wage and hour laws, which is not surprising given
    the lack of any indication that the agency anticipated at the time
    the FLSA's "requirements" rather than to a fixed, minimum dollar
    amount.
    - 45 -
    of the regulations' promulgation that state wage and hour laws
    would apply to domestic workers.       See infra Section III.B.3.a.
    Thus, the fact that a state wage and hour law might increase host
    family costs beyond what they would be in the absence of such a
    law is not, in and of itself, evidence that demonstrates that such
    a law would impede the accomplishment of the federal objective
    reflected in the text of the DOS regulations.   Cf. Williamson, 
    562 U.S. at 332
    .
    From all one can tell from the text of these provisions,
    in other words, the Au Pair Program operates parallel to, rather
    than in place of, state employment laws that concern wages and
    hours and that protect domestic workers generally, at least with
    respect to the obligations that such state law wage and hour
    measures impose on host families to do more than what the FLSA
    itself requires.   Thus, the text of au pair exchange program
    regulations themselves does not supply the affirmative evidence
    that the state measures at issue will frustrate the federal
    scheme's objectives that the plaintiffs need to identify if they
    are to meet their burden to show obstacle preemption.
    The plaintiffs ask us, however, to consider the Au Pair
    Program in light of the DOS "Exchange Visitor Program" Regulations
    as a whole.    They point out that the regulations that govern
    certain other exchange visitor programs expressly require sponsors
    to ensure that program participants are paid "the higher of . . .
    - 46 -
    [t]he applicable Federal, State or Local Minimum Wage," 
    22 C.F.R. § 62.32
    (i)(1)(i).14      They note that, by contrast, the section of
    the "Exchange Visitor Program" regulations that governs the au
    pair    exchange   programs   does     not.    See   
    id.
       § 62.31(j).     The
    plaintiffs contend that this relative silence gives rise to an
    inference of a ceiling-setting intent on the part of the DOS by
    negative implication.
    But, these other regulatory measures are themselves
    sponsor focused, and the plaintiffs do not suggest that, just
    because     sponsors   must   ensure    that   the   participants   in   those
    programs must comply with those state laws, those participants are
    barred from enforcing those state laws directly against their
    employers, insofar as their employers fail to comply with them.15
    In addition, the regulatory provisions that impose the obligation
    14 The   summer   work-travel    regulations,     
    22 C.F.R. § 62.32
    (i)(1)(i), the teacher program, 
    id.
     § 62.24(f)(5), and the
    camp counselor program, id. § 62.30(f), include references to the
    applicability of state and local wage laws or state that exchange
    visitors should be paid like their American counterparts.
    15 Consistent with this conclusion, the plaintiffs do not
    dispute that au pair participants are "employees" under the FLSA,
    as the DOL determined them to be in 1997 and as the au pair exchange
    program regulations have long accepted. 62 Fed. Reg. at 34,633.
    Nor do the plaintiffs appear to dispute that, if an au pair
    participant could show that she had worked a given number of hours
    in a week, then she would appear to have the independent statutory
    right as an "employee" under the FLSA to seek compensation for
    that amount of work from her host family as her "employer" if she
    had not in fact been paid the required wage. The plaintiffs appear
    to accept this fact, moreover, notwithstanding that the Au Pair
    Program itself does not confer that right on the participants.
    - 47 -
    on the sponsors of those other programs are silent with respect to
    whether the DOS understood that the participants in them would be
    preempted from enforcing state wage and hour laws against their
    employers unless their sponsors were obliged to ensure that those
    employers complied with those laws.          See, e.g., Exchange Visitor
    Program -- Summer Work Travel, 
    76 Fed. Reg. 23,177
    , 23,177-78 (Apr.
    26, 2011) (to be codified at 22 C.F.R. pt. 62).              In consequence,
    the fact that the DOS did not impose that same obligation on Au
    Pair Program sponsors does not show by negative implication that
    the DOS must have intended for the Au Pair Program to impose such
    a preemptive bar.
    There is, moreover, textual evidence in other provisions
    of the DOS "Exchange Visitor Program" regulations that appears to
    be at odds with the inference that the plaintiffs ask us to draw
    from the relative silence of the regulations that govern the Au
    Pair   Program.     The   plaintiffs   do    not   dispute    that   au   pair
    participants are "employees" within the meaning of the FLSA.              The
    plaintiffs thus appear to accept that the Au Pair Program does
    have an "employment component[.]"           
    Id.
     § 62.11(a).     The general
    provisions of the "Exchange Visitor Program" regulations, however,
    expressly contemplate that state laws that regulate employment --
    and thus that regulate an employee's wages and hours -- will
    independently protect participants in exchange visitor programs
    that have an "employment component."          Id.; see id. § 62.10(b)(9)
    - 48 -
    (providing that sponsors must also provide "clear information and
    materials"      to       program     participants,      including      information
    pertaining      to   "employee      rights     and   laws,   including   workman's
    compensation").
    The plaintiffs' only response is that, at least with
    respect to participants in the au pair exchange program, this
    general "employment component" provision must be referring merely
    to employee rights and laws other than state wage and hour laws.
    But, the ordinary meaning of the phrase "pertaining to employment,"
    see id. § 62.11(a), would not appear to exclude wages and hour
    laws.     The provision also applies, by terms, to any exchange
    visitor program with an "employment component."                   The plain text of
    the "employment component" provision thus provides no support for
    reading in the plaintiffs' preferred implicit limitation -- let
    alone     for    reading       in     that      au-pair-exchange-program-based
    limitation and then also drawing the negative inference from
    relative silence that the plaintiffs ask us to draw.
    Such    a     limitation    on      that   "employment      component"
    provision also is not compelled by the fact that sponsors of some
    exchange visitor programs must ensure that employers comply with
    state wage and hour laws.             It would be odd to construe the more
    onerous    directive       that     requires     sponsors    of   certain   visitor
    exchange programs to ensure employer compliance with state wage
    and hour laws to limit the scope of the less onerous directive
    - 49 -
    that requires all sponsors merely to have detailed knowledge of
    such    laws    and   to    convey    information    about     them   to   program
    participants.         Per the regulations, moreover, sponsors clearly
    must have detailed knowledge of some state employment laws --
    including       concerning      workman's       compensation     --     that    the
    regulations do not require them to ensure that employers follow.
    See id. §§ 62.11, 62.10(b)(9).
    We do not mean to challenge the plaintiffs' assertion
    that the au pair exchange program regulations do not themselves
    oblige sponsors (let alone host families) to require that au pair
    participants receive the minimum wage that a state would require
    that they be paid.          The regulations plainly do not.          But, the fact
    that the regulations do not themselves impose on host families an
    obligation to comply with state wage and hour laws that the DOS
    may enforce against them does not supply the needed affirmative
    evidence    that      the    regulations    were   intended     to    preempt   the
    enforcement of such a state law obligation against those families.
    Finally, we find it significant that, although the DOS's
    au pair exchange program regulations make no reference to state
    wage and hour laws, they do refer to the expressly non-preemptive
    FLSA.   It is conspicuous -- insofar as the DOS is said to have the
    asserted    preemptive       intent   --   that,    in   cross-referencing      the
    FLSA's expressly non-preemptive requirements, the provision says
    nothing similarly express to indicate that the au pair exchange
    - 50 -
    program regulations preempt independently conferred wage and hour
    rights that the FLSA does not itself preempt.
    In   sum,   the   text   of    the   au   pair   exchange    program
    regulations and the "Exchange Visitor Program" regulations more
    generally do not supply the requisite affirmative evidence that
    the state law measures would pose an obstacle to the accomplishment
    of the purposes and objectives of the Au Pair Program.                In fact,
    the text of the regulations reflects the DOS's intention to ensure
    that the regulations would accommodate the DOL's determination
    that au pair participants are employees who are entitled to be
    protected by an independent wage and hour law that is not itself
    preemptive.    The regulations also reflect the fact that the DOS
    contemplated that state employment laws would protect exchange
    visitor program participants from their employers.            Thus, if there
    is a basis for concluding that the relevant DOS provisions preempt
    wage and hour laws that the FLSA does not itself preempt, that
    conclusion must find support somewhere other than in the text of
    the DOS regulations themselves.
    3.
    The plaintiffs argue that the regulatory history lends
    the necessary support that, as we have explained, the regulatory
    text fails to supply.   The plaintiffs point specifically, however,
    only to a few brief passages from the agency commentary that
    accompanied the 1994 and 1995 precursors to the current section of
    - 51 -
    the DOS regulations, which at the time had been promulgated by the
    USIA.   We do not disagree that this history may be relevant to our
    inquiry into agency intent. See Geier, 
    529 U.S. at 884-85
     (finding
    regulations to have a preemptive effect without clear text to that
    effect based on the regulatory history). But, we conclude that,
    when considered in context, that history does not provide the
    affirmative evidence that the plaintiffs must identify to meet
    their burden to show obstacle preemption.
    a.
    The   plaintiffs   first    point   to   a   passage   from   the
    commentary that accompanies the USIA's 1994 Interim Final au pair
    exchange program regulations.    That passage refers to the need for
    there to be "uniform compensation" for au pair participants.             59
    Fed. Reg. at 64,298.    The plaintiffs contend that this reference
    shows, quite clearly, that the agency did intend to establish the
    nationally uniform compensation system on which their obstacle
    preemption claims are premised.       But, the context shows otherwise.
    The agency commentary indicates that a central concern
    for the agency at that time was whether "an employer/employee
    relationship [was] established between the au pair and the host
    family" -- and thus whether the FLSA applied to that relationship.
    See id.   The commentary shows that the agency thought that the au
    pair-host family relationship presented an analogous relationship
    to that of domestic workers and their employers under the FLSA.
    - 52 -
    The commentary further shows that the agency was inclined to
    "defer[] to more appropriate authorities" as to the nature of that
    relationship rather than to make its own independent judgment.
    Id.    Nevertheless, the commentary goes on to explain, the agency
    had decided to base the weekly "Stipend" amount that sponsors would
    have to ensure that au pair participants received on the FLSA's
    wage and hour requirements for live-in domestic workers, assuming
    the au pair participants provided 45 hours of childcare services
    in that week, as if those FLSA requirements did apply of their own
    accord.   See id. at 64,298-300.
    It is at this point in the commentary that the reference
    to "uniform compensation" appears.           The reference arose because,
    even after having decided to peg the stipend to an amount that
    would ensure compliance with the FLSA's floor -- insofar as the
    FLSA   turned   out   to   govern    of   its   own   force   the   au   pair
    participant-host family relationship -- the agency still faced a
    choice.   The agency needed to determine how high to set that FLSA-
    compliant weekly compensation amount.
    The USIA noted in the accompanying commentary that this
    choice arose due to a DOL rule that implemented the 1975 FLSA
    amendments that governed domestic workers.            Id. at 64,298.     That
    DOL rule permitted employers of live-in domestic workers to deduct
    from those workers' wages either a fixed credit in the amount of
    $36 per week for their room and board costs or their actual room
    - 53 -
    and board costs on an itemized basis, so long as employers who
    chose the latter option kept records to support those itemized
    deductions.     40 Fed. Reg. at 7406 (DOL regulation setting maximum
    deductions).
    Given that DOL rule, if the agency pegged the weekly
    stipend amount to a wage due a domestic worker for 45 hours of
    labor under the FLSA that was based on the $36 fixed credit that
    the    DOL    permitted   employers      to     take,       then   the   resulting
    compensation amount -- to be FLSA compliant -- would have to be a
    fixed and thus uniform dollar amount for every family of at least
    -- "not less than" -- $155 a week.             59 Fed. Reg. at 64,298.          But,
    if the agency instead pegged the amount to the itemized deductions
    that   host    families   were      permitted    to    claim   under     the   DOL's
    implementing regulations, then that amount (though still FLSA-
    compliant) would not only potentially be much lower, it also would,
    necessarily, not be uniform across families.                 For, in that event,
    that amount necessarily could vary from family to family (even
    within   a    state)   with   the    amount     of    the   legitimate    itemized
    deductions that each host family might choose to claim.                   Id.
    The USIA, having considered both approaches, explained
    in the commentary that it had decided to "adopt[] the $36 credit
    approach . . . in order to ensure that all au pair participants
    receive uniform compensation."            Id.        Thus, the context for the
    - 54 -
    reference to "uniform compensation" on which the plaintiffs rely
    shows the following.
    The USIA made the reference to its interest in uniform
    compensation only in the course of attempting to explain why,
    having decided to peg the weekly compensation amount that sponsors
    would have to ensure to an amount that would "not [be] less than"
    the   FLSA    floor,   it   had     chosen     as    between   two   possible
    FLSA-compliant amounts the one that was uniform (because pegged to
    the fixed credit) rather than the one that was variable (because,
    pegged to the itemized option).          Accordingly, the reference to
    "uniform compensation" does not provide the needed affirmative
    evidence that the agency had an independent interest in ensuring
    the   kind    of   nationwide     uniformity    in    au   pair   participant
    compensation that would necessitate the imposition of a ceiling on
    the compensation that host families could be required by a state
    to pay an au pair participant.
    In fact, no mention is even made of any state wage and
    hour laws, even though there is extensive discussion in the agency
    commentary of the expressly floor-setting -- rather than ceiling-
    setting -- FLSA.       Nor is the absence of any such reference so
    surprising that we must assume that the agency failed to mention
    such state wage and hour measures only because it understood that
    they would be preempted.
    - 55 -
    The regulations then -- just like the DOS regulations
    now -- purported only to define the obligations of the sponsors of
    au pair exchange programs.       It is hard to leap from the fact that
    a sponsor was not obliged to ensure that host families comply with
    those wage and hour laws to the conclusion that host families
    themselves were not obliged to do so, such that au pair employee
    participants could not enforce the rights that they otherwise would
    have under such laws against their host family employers. In fact,
    it is not clear that the agency was even aware at the time that
    state wage and hour laws protected the rights of domestic workers.
    Against that uncertain state law landscape, it would have made
    sense for the agency to have been concerned only with defining the
    sponsors' obligation as to the federal minimum wage, which the
    accompanying agency commentary makes clear that the agency was
    aware at the time might protect au pair participants.
    b.
    The    plaintiffs'    other    evidence   from   the    regulatory
    history   comes   from    the   commentary   that    accompanies    the   1995
    revisions to the Au Pair Program regulations.               The plaintiffs
    point, first, to a portion of this commentary in which the agency
    states: "the programmatic need for a uniform wage remains."                60
    Fed. Reg. at 8551.       The plaintiffs then point to a portion of the
    commentary in which the agency describes a possible future revision
    by the DOL of its domestic worker regulations concerning room-and-
    - 56 -
    board costs deductions by employers of domestic workers.                Id.
    That portion notes that, once made, that revision would "eliminate
    the need for host families to keep individualized records."             Id.
    But, when considered in context, these passages do not provide the
    basis for drawing the inference with respect to obstacle preemption
    that the text of the regulations themselves fail to supply.
    With   respect   to   the   agency's    statement   that    "the
    programmatic need for a uniform wage remains," the context shows
    that host families had contended that the $155 stipend amount in
    the 1994 regulations was too high.         Id.   The host families were of
    that view because they contended that, in using the $36 fixed
    credit to generate the $155 amount, the USIA was relying on an
    outdated -- and thus artificially low -- means of estimating the
    actual room and board costs of host families as of 1995.          Id.   The
    host families thus had argued that the agency should permit host
    families to deduct their actual room and board costs on an itemized
    basis, as was permitted by that same DOL regulation, in order to
    account for inflation over the last decades.          Id.
    The agency found this contention persuasive, in part,
    but then added: "however, the programmatic need for a uniform wage
    remains."   Id.    For that reason, the agency opted for a new stipend
    amount -- $115 a week -- that would be lower than the prior one
    but still tied to a fixed dollar amount rather than to one that
    would vary with a particular host family's itemized deductions.
    - 57 -
    Id.   That revised approach would permit host families to claim
    itemized deductions but only up to an amount $40 greater than the
    $36 fixed credit amount, assuming that host families documented
    the up-to-$40-worth of itemized deductions with the records that
    the DOL rule required for deductions claimed on such an itemized
    basis.   Id.
    Thus, once again, the passage that refers to uniformity
    as an agency interest appears in a specific context.       That context
    reveals that the reference to uniformity reflects the agency's
    continued   interest   in   setting   the   compensation   amount   that
    sponsors would be required to ensure was paid at an amount at least
    equal to the FLSA minimum but still uniform for all host families
    (because pegged to a fixed dollar amount greater than the FLSA's
    $36 fixed credit deduction option) rather than as low as the FLSA
    minimum but potentially variable, even within a state, as to each
    host family (because pegged to the FLSA's itemized deductions
    option).    In context, then, the reference does not concern the
    distinct issue on which the obstacle preemption inquiry turns:
    whether the federal agency, in establishing this uniform floor for
    the amount that a sponsor must ensure that an au pair participant
    is compensated, intended also to set a nationally uniform wage
    ceiling, to ensure uniformity across states, that would preclude
    au pair participants from enforcing state wage and hour laws
    against their host families.
    - 58 -
    The commentary also supplies important context for the
    reference to the elimination of recordkeeping burdens that appears
    in the accompanying agency commentary to this iteration of the
    USIA regulations.   The agency explained in that commentary that it
    set the new stipend amount $40 lower than it had set it in the
    1994 interim final regulations.      The agency explained that it had
    done so because the DOL had by then proposed a domestic worker
    regulation that would raise the cap on the fixed credit that
    employers of domestic workers could claim for room and board costs
    to an as-yet unknown amount.   Id.    Thus, the agency explained, the
    DOL's proposed revision to its domestic worker rule would -- once
    finalized -- substantially increase the fixed credit amount while
    still providing an option for claiming itemized deductions for
    room and board costs if supported by adequate records.16     Id.; see
    16  We note that the regulatory history references a
    "programmatic need for a uniform wage." 60 Fed. Reg. at 8551
    (emphasis added). It appears that the "programmatic need" for
    uniformity was a need that the agency was attributing to the
    privately conducted "programs," rather than to the agency itself,
    presumably because the "programs" had an interest in opposing
    itemized deductions. A duty to ensure that au pair participants
    received a fixed-dollar-amount-based stipend each week, after all,
    is more easily satisfied than is a duty to ensure that the
    participants receive a stipend amount from their host families
    that would depend on the legitimacy of the itemized deductions
    that individual host families claimed. See id. This understanding
    comports with the agency's explanation that, in the end, it chose
    to balance the "programmatic need" for uniformity with the needs
    of host families, who favored a variable stipend based on itemized
    deductions. Id. In this way, too, then, the passage from the
    agency commentary on which the plaintiffs rely appears to provide
    - 59 -
    also Application of the Fair Labor Standards Act to Domestic
    Service, 
    58 Fed. Reg. 69,310
     (Dec. 30, 1993) (to be codified at 29
    C.F.R. pt. 552) (proposed DOL rule permitting a fixed credit amount
    tied to the federal hourly minimum wage and deduction of actual
    costs supported by adequate records).   The agency then noted that,
    once the DOL did so revise that fixed credit cap, the need for
    host families to keep records to claim deductions above the $36
    fixed credit would thereby be eliminated.   
    Id.
    Given this context, the reference to the elimination of
    the need to undertake recordkeeping burdens fails to indicate that
    the agency intended to eliminate the imposition of independently
    imposed recordkeeping burdens on host families.     In fact, as we
    have explained, the 1995 regulations affirmatively permitted host
    families to claim some itemized deductions under the DOL domestic
    workers rule in a way that the 1994 interim final regulations --
    due to the higher compensation floor that had been set -- did not.
    But, the 1995 regulations permitted families to claim the itemized
    deductions without suggesting that, in doing so, they would not
    have to comply with the recordkeeping requirements for taking such
    itemized deductions that the DOL regulation imposed of its own
    little support for concluding that the agency's interest in
    uniformity reflected an interest in establishing a nationally
    uniform compensation ceiling applicable in every state rather than
    merely a compensation floor that would not depend on the deductions
    claimed by particular families within any state.
    - 60 -
    accord.          40        Fed.    Reg.   at    7406    (1975        DOL     regulations);
    Administrative Changes, 
    44 Fed. Reg. 6715
     (Feb. 2, 1979) (to be
    codified at 29 C.F.R. pt. 552) (1979 amendments). To the contrary,
    the agency noted that this approach "will ensure adherence to
    federal law,"          60 Fed. Reg. at 8551, which further reflects the
    agency's understanding that the FLSA's (non-preemptive) minimum
    wage    and     attendant         recordkeeping     requirements       would       apply   as
    independent legal obligations to which host families may be subject
    separate and apart from any obligation that the USIA's au pair
    exchange program regulations imposed on them.
    Moreover, as we shall next see, the agency ultimately
    opted to require sponsors to ensure that au pair participants
    received weekly compensation based on a calculation that would be
    "in conformance with the requirements of" the FLSA. 
    22 C.F.R. § 62.31
    (j)(1); 62 Fed. Reg. at 34,634.                  Significantly, the agency
    did so at a time when those FLSA "requirements" contemplated that
    employers could deduct from the wages of domestic workers the
    actual costs of room and board on an itemized basis only if such
    deductions were backed up with adequate supporting records.                                See
    
    29 C.F.R. § 552.100
    (c)-(d);           Application      of     the       Fair   Labor
    Standards Act to Domestic Service, 
    60 Fed. Reg. 46,766
    , 46,768
    (Sept. 8, 1995) (to be codified at 29 C.F.R. pt. 552).
    It      is    worth    noting,     too,   that,    in        the    commentary
    accompanying the 1995 regulations, the USIA explained for the first
    - 61 -
    time that it had been "specifically advised" by the DOL that au
    pairs were "employees" of their host families and thus subject to
    the FLSA.   60 Fed. Reg. at 8550.     The USIA also explained in that
    same commentary that it would defer to the DOL on that issue.         Id.
    Yet,   in   providing   the   DOL's   analysis   that   supported    that
    conclusion, the USIA did not refer to any potential conflict
    between the imposition of the FLSA's obligations on host families
    and any USIA interest, such as the goal of cultural exchange.         See
    id. at 8550-51.    Nor did the USIA express reservations about the
    DOL's characterization of the au pair participant-host family
    relationship as an employee-employer relationship.        Nor, finally,
    did the USIA assert that, even though the FLSA's requirements are
    not preemptive of state wage and hour laws, the USIA's regulations
    keyed to those very same requirements were.       See id.
    If anything, then, the accompanying agency commentary
    indicates that the regulations were crafted to accommodate the
    fact that an independent wage and hour law -- the FLSA -- might
    treat the relationship between au pair participant and host family
    to be one between employee and employer and thus give independent
    rights to the former that could be enforced against the latter.
    But, that independent federal wage and hour law itself sets only
    a floor for the compensation and record keeping requirements that
    states may exceed through their own wage and hour laws.             It is
    thus hard to see how either the USIA's 1995 au pair exchange
    - 62 -
    program regulations or the agency commentary to them provides the
    requisite support for the conclusion that the agency must have
    implicitly intended to establish a preemptive ceiling on wage and
    hour requirements that no state could exceed; no such state law
    measures were even mentioned in either the regulations themselves
    or the accompanying agency commentary.         It is especially hard to
    see how those materials provide such support, insofar as the state
    law obligations would be imposed on host families as the employers
    of au pair participants, given that the regulations, by their
    terms, purported to impose obligations that the DOS could enforce
    only on the sponsors.
    c.
    The one last piece of the regulatory history that the
    parties discuss -- the USIA's 1997 revision to the au pair exchange
    program regulations -- supports the same conclusion. That revision
    introduced, for the first time, the language on au pair participant
    compensation that appears in the current version of the DOS's au
    pair exchange program regulations.       See 60 Fed. Reg. at 46,768.
    The language refers to such compensation as a "wage" --
    and thus calls to mind an employment relation -- and pegs the
    amount not to a fixed-dollar number but to a calculation based on
    the "requirements" of the FLSA, which, of course, are themselves
    expressly   not   preemptive.   Id.      The   USIA   explained   in   the
    commentary to the 1997 version of the regulations that accompany
    - 63 -
    these provisions, moreover, that, as of that time, the DOL had
    "determin[ed]" that au pair participants were "employees" under
    the FLSA and thus that they "must" be compensated in accordance
    with its terms.    62 Fed. Reg. at 34,633.   The 1997 commentary goes
    on to explain that the USIA had thus decided -- as it had long
    suggested that it would -- to defer to the DOL's final view of
    that question.    Id.
    Given this context, it is notable that the accompanying
    agency commentary says not a word about either the need for
    "uniform"    compensation   or   the   elimination   of   recordkeeping
    burdens.    See id. at 34,632-33.   Once the USIA had decided to defer
    to the DOL's final determination that au pair participants had to
    be treated as "employees" under the FLSA, it would appear, the
    USIA's only interest was in obliging sponsors to ensure that au
    pair participants got at least what protection they would be due
    under the FLSA, whatever its "requirements" were.         Id.   But that
    federal interest may be fully accomplished by merely setting a
    FLSA-pegged weekly compensation floor that sponsors must require
    that host families meet --- and a floor that could vary based on
    the itemized deductions, if backed by supporting records, that a
    given host family might claim for room and board costs.              The
    fulfillment of that federal interest would not require the agency
    to make that floor also do double duty as a ceiling that no state
    could exceed in setting the obligations of host families, as a
    - 64 -
    species of employer, with respect to those whom they employed to
    provide in-home childcare services.
    Nor is there anything anomalous about concluding that
    the USIA had no interest in making that floor do such double duty.
    As discussed above, it is not clear whether the USIA was even aware
    that any state law measures protecting the wage and hour rights of
    domestic workers existed.     See supra Section III.B.3.a.      A federal
    agency would have acted quite sensibly, therefore, in obliging
    sponsors of this type of exchange visitor program to be responsible
    for requiring compliance only with clearly established federal
    statutory wage and hour standards, while leaving the employer-
    host-families responsible for ensuring that they complied with any
    generally applicable state wage and hour law requirements that
    might emerge.    Thus, contrary to the plaintiffs' contention, the
    fact that there is no history of federal agency attempts to oblige
    sponsors to require host family compliance with state wage and
    hour laws hardly supplies a supportable basis for concluding that
    the   agency   must   have   intended   to   preempt   the   participants
    themselves from enforcing such state law measures against their
    host families.
    C.
    The plaintiffs separately point to what they claimed
    would be the adverse practical impact on the Au Pair Program of
    the application of the state law measures to host families.          The
    - 65 -
    plaintiffs contend that, if those measures were applicable to host
    families as the employers of au pair participants, then the
    enforcement of those measures would make participation in the
    program for host families so costly that it would preclude "many,
    and probably most" families from doing so.           The plaintiffs also
    contend that such application of the Massachusetts measures would
    formalize what they portray as a more informal host-family-au pair
    participant relationship in ways that the federal government could
    not possibly have intended.
    This line of argument rests in part on the disputed claim
    that,   under    Massachusetts   law,     domestic     workers   must   be
    compensated for sleep and meal periods even if they are completely
    relieved of job duties and free to leave the premises.            See 
    940 Mass. Code Regs. 32.02
     (defining "working time").         But, we have no
    reason here to disregard the Attorney General's assertion about
    the proper construction of state law, given the lack of clarity in
    the relevant provisions.    See Amerijet Int'l, Inc. v. Miami-Dade
    Cty., 
    627 F. App'x 744
    , 749 (11th Cir. 2015) ("In evaluating the
    [Appellant's] facial challenge, we must consider the county's
    authoritative constructions of the ordinance, including its own
    implementation    and   interpretation     of   it."     (alteration    in
    original)(quoting Forsyth Cty. v. Nationalist Movement, 
    505 U.S. 123
    , 131 (1992))).
    - 66 -
    Moreover,        the   plaintiffs'        assertions      that        the
    Massachusetts measures would preclude large numbers of families
    from participating in the Au Pair Program are cast in conspicuously
    speculative terms ("many, probably most"). (Emphasis added).                     The
    Massachusetts wage and hours measures are generally applicable to
    domestic workers, whether they participate in the au pair exchange
    program or not.      The plaintiffs' complaint provides no basis for
    surmising, however, that families who otherwise would have become
    host families in order to obtain needed in-home childcare services
    would opt in large numbers to forgo obtaining such services
    altogether in order to avoid the costs imposed by the DWBORA and
    the Massachusetts Fair Wage Law.           Yet, if such families would not
    opt to forgo all such services, then the plaintiffs have failed to
    explain why those families would opt out of the Au Pair Program,
    for there is simply no way for such families to obtain such
    services   from   anyone     --   au    pair    participants    or   not    --    in
    Massachusetts without incurring the costs imposed by the DWBORA
    and the Massachusetts Fair Wage Law.
    The    plaintiffs'     assertions      about   the   impact     of    the
    administrative burdens and recordkeeping obligations imposed by
    the Massachusetts measures suffer from similar problems.                         The
    assertions do not, for example, take account of the fact that
    similar    (though    not     identical)        burdens   and    recordkeeping
    requirements are already imposed by the FLSA on host families.
    - 67 -
    Compare 
    29 C.F.R. §§ 552.100
    , 552.110, with Mass Gen. Laws ch.
    151, § 15, and Mass Gen. Laws ch. 149, § 190(l). But see Mass.
    Gen. Laws ch. 149 § 190(l)(v)-(ix) (requiring that host families
    keep   records   of    various   employment      policies,    such   as   job
    responsibilities      and   procedures   regarding    termination).       The
    assertions thus fail to show why the differential recordkeeping
    burdens would be so transformative as to require the conclusion
    that they would prevent the Au Pair Program from serving its goal
    of promoting international cultural exchange.
    This impact-based line of argument, however, ultimately
    suffers   from   a    more    serious    flaw,   which   we    conclude    is
    determinative.       In asking us to infer a ceiling-setting agency
    intent on the basis of only speculative predictions about the
    future effects on host family participation of the application of
    state laws, the plaintiffs are necessarily asking us to engage in
    precisely the sort of "freewheeling judicial inquiry" into the
    intention of the federal agency that we are supposed to avoid in
    evaluating an obstacle preemption claim.             Whiting, 
    563 U.S. at 607
    ; see Boyle, 
    487 U.S. at
    507 n.3 (requiring at least evidence
    of a "significant conflict").       This is not a case, we emphasize,
    in which there is an extensive regulatory history replete with
    agency commentary that provides support for drawing the inference
    that the agency had deliberately intended to set both a floor with
    which the private actors would have to comply and a ceiling on the
    - 68 -
    additional regulatory burdens that a state could impose on them.
    Compare Geier, 
    529 U.S. at 875-78, 885-86
    , with 
    id. at 910-11
    (Stevens, J., dissenting) ("[T]he Court identifies no case in which
    we    have   upheld   a   regulatory     claim    of   frustration-of-purposes
    implied conflict pre-emption based on nothing more than an ex post
    administrative litigating position and inferences from regulatory
    history and final commentary." (second emphasis added)).                  Rather,
    neither      the   text   nor   the      regulatory     history   affirmatively
    indicates that the federal government made such a deliberate,
    ceiling-setting       choice,     and,    other     provisions    indicate      the
    opposite.     In such circumstance, speculation about future impacts
    supplied by the plaintiffs themselves cannot satisfy their burden
    to show the requisite -- implicit -- preemptive intent.
    IV.
    We recognize that the DOS, as reflected in its amicus
    filing, reads its current regulations -- as well as the regulatory
    history that we have just reviewed -- differently than we do.                   We
    thus consider the contentions that the DOS makes, too.                  Geier, 
    529 U.S. at 883
    ; Williamson, 
    562 U.S. at 335-36
    ; see also Kisor v.
    Wilkie, 
    139 S. Ct. 2400
    , 2418 n.6 (2019) (reaffirming courts’
    ability to defer to "agency interpretations advanced for the first
    time in legal briefs" where there is "no reason to suspect that
    the    interpretation     [did]    not    reflect      the   agency's    fair   and
    - 69 -
    considered judgment on the matter in question" (quoting Auer v.
    Robbins, 
    519 U.S. 452
    , 462 (1997))).
    In doing so, however, we are mindful that we may not
    defer to an "agency's conclusion that state law is preempted."
    Wyeth,    
    555 U.S. at 576
    .      Instead,   we   must   attend    to    the
    "thoroughness, consistency, and persuasiveness" of the agency's
    explanation of how state law affects the federal regulatory scheme
    that the agency administers.            
    Id. at 577
    .     And here, as we will
    explain, the DOS's explanation, even if not in conflict with any
    previously articulated and well-considered DOS explanation, fails
    to warrant a finding of either field or obstacle preemption.
    Like the plaintiffs, the DOS points to the fact that the
    "Exchange Visitor Program" regulations for certain other exchange
    visitor programs, unlike those for the Au Pair Program, explicitly
    reference state and local minimum wage laws.                   See 
    22 C.F.R. § 62.32
    (i)(1)(i).         The DOS contends that this aspect of the
    regulations shows that when the DOS "intends to require payment in
    accordance with state and local law for [other exchange visitor
    program] participants the Department say[s] so expressly[.]"                  But,
    as   we   have   noted,      by   terms,   the   "Exchange   Visitor    Program"
    regulations address only the obligations that sponsors must meet
    in order to avoid the sanctions that the DOS may impose on them
    under the regulations.            The regulations do not, by terms, purport
    to define the obligations of the employers themselves that those
    - 70 -
    whom they employ may enforce against them.                 See supra Section
    III.A.2.
    The DOS does not attempt to account for this disjuncture
    between the Au Pair Program's focus on the obligations of sponsors
    and the state wage and hour measures' focus on the obligations of
    the employers to the domestic workers whom they employ.                The DOS
    merely asserts that, because sponsors of au pair exchange programs
    are not required to ensure that employers comply with state wage
    and hour laws, while the sponsors of other exchange visitor
    programs are so required, the participants in au pair exchange
    programs may not independently ensure that their employers do
    comply with those state laws.         There is no indication, however,
    that the participants in those other exchange visitor programs
    would be prevented from enforcing their state law wage and hour
    rights   against   their   employers      unless    the    sponsors   of   those
    programs   were    required   to   show   that     the    employers   of   those
    participants complied with them.          The DOS thus fails to provide a
    persuasive explanation for drawing the negative inference that,
    because au pair exchange programs are not required to ensure such
    compliance, au pair participants may not enforce state wage and
    hour rights against their employers.
    The DOS also asserts that the federal obligations on
    sponsors to require that au pairs are paid "in conformance with
    the requirements of the FLSA" based on the au pair having worked
    - 71 -
    45 hours in a week should be understood to be a preemptive ceiling
    on what the au pair participant may claim as a wage from her host
    family.   But, as we have explained, that language simply does not
    by terms establish such a ceiling.        See supra Section III.B.2.
    The DOS separately contends that the regulations that
    govern the Au Pair Program should be construed to be preemptive in
    the same way that the federal statute that authorized the President
    of the United States to impose sanctions on Burma that was at issue
    in Crosby v. National Foreign Trade Council, 
    530 U.S. 363
    , 380
    (2000),   was   construed   to   be.      The   DOS   contends   that   the
    regulations, like the federal Act in Crosby, are "drawn not only
    to bar what they prohibit but to allow what they permit."               
    Id.
    But, in Crosby, as the Court expressly recognized, Congress's
    purpose was clear -- to give the President full discretion in
    regard to trade with "Burma."     
    Id. at 374-76
    .      It is not similarly
    clear that, in setting the compensation obligation of a sponsor of
    an au pair exchange program -- enforceable only by the DOS against
    that sponsor -- the regulatory scheme's purpose was to set not
    only the minimum amount that the sponsor must ensure that au pair
    participants must receive but also a ceiling on what a state may
    require a host family to pay that au pair participant.           In fact,
    the wages and hours obligation that the DOS imposes on sponsors is
    pegged to the requirements of a federal statute that itself makes
    clear that the floor that it sets for the wage that employers must
    - 72 -
    pay is not also a ceiling on what states may require them to pay.
    See 
    29 U.S.C. § 218
    .
    Turning      to   the   DOS's   discussion     of   the   regulatory
    history, the DOS points only to the very same passages in the
    agency commentary that we have already reviewed.               The DOS does not
    purport to examine the context within which the passages appear.
    Instead, it seizes on certain phrases in isolation.                  As we have
    explained, though, considered in context, the passages that the
    DOS invokes show that the agency intended to establish a uniform
    rather than variable compensation floor -- pegged to the FLSA
    minimum -- that sponsors would be obliged to ensure was met.                 See
    supra Section III.B.3.a.           The agency interest in ensuring that
    kind of uniformity, however, accords with the agency having merely
    established a floor for sponsors to meet.           The DOS thus fails to
    explain   why   these    references    affirmatively      indicate    that   the
    agency also had the requisite ceiling-setting intent.
    There is, moreover, regulatory text that appears to
    point directly against the DOS's view.          Specifically, DOS appears
    to acknowledge that the au pair regulations include an "employment
    component,"     and   that   the    general   "Exchange    Visitor     Program"
    regulations' requirement that sponsors who "work with programs
    with an employment component" must have "Responsible Officers" who
    have "a detailed knowledge of federal, state, and local laws
    - 73 -
    pertaining to employment" applies to the Au Pair Program.           See 
    22 C.F.R. § 62.11
    (a).
    To respond to this seemingly problematic language, the
    DOS contends that state wage and hour laws only apply to "Exchange
    Visitor   Programs"   that   have    additional,   specific   regulations
    regarding state laws on top of the general regulations, such as
    the   summer   work-travel    program.       According   to   the    DOS's
    construction of the regulations, the general "Exchange Visitor
    Program" regulations' requirement that sponsors have "Responsible
    Officers" who understand all state laws that are relevant to their
    programs applies to the Au Pair Program only "with respect to
    matters" beyond wage and hour laws, such as state negligence laws.
    But, insofar as this assertion by the DOS depends on our granting
    the negative inference that the plaintiffs ask us to draw from the
    requirement that sponsors of other exchange visitor program ensure
    that employers of the participants in those programs do comply
    with such laws, we have already explained why such an inference is
    unwarranted.    See supra Section III.B.2.         And, insofar as this
    assertion does not depend on that premise, it cannot be squared
    with the plain text of the regulations, for reasons that we have
    already explained.    See id.
    Thus, while we do owe respectful deference to the DOS's
    own view of its regulations, the portions of the regulatory text
    and the passages in the underlying regulatory history that the DOS
    - 74 -
    invokes to support the assertions that it makes about them simply
    do not support those assertions.    And, of course, an agency's mere
    "conclusion that state law is pre-empted" is not one to which we
    may defer.    Wyeth, 
    555 U.S. at 576-77
    .
    There is one last set of materials to which the DOS --
    and, in passing, the plaintiffs -- point: a series of agency
    guidance documents and fact sheets concerning changes to the
    federal minimum wage that were issued by the USIA and the DOS
    between 1997 and 2007.    The DOS does not contend that we owe such
    material any deference.      But, the DOS does contend that these
    materials show that the Au Pair Program regulations were long
    understood by the agency itself to oust state minimum wage laws.
    We do not agree.
    The 1997 agency documents merely clarify that federal
    changes to minimum wage laws affect the stipend and wage calculated
    in the 1995 regulations.      Thus, these guidance documents serve
    only to reinforce the conclusion -- already evident from the text
    -- that the DOS regulations apply only to sponsoring organizations
    and that Au Pair Program participants' actual entitlement to wages
    that they may enforce against their host families comes from the
    FLSA -- not the DOS regulations.         In particular, the documents
    warn host families that if they fail to "abide by the . . . au
    pair stipend increases" they are "in violation of federally-
    mandated minimum wage law," not DOS regulations.      These documents
    - 75 -
    thus show, at most, that state wage and hour laws were not
    considered, not that they were considered and preempted.
    The 2007 fact sheet does refer to a fixed-dollar amount
    for the minimum weekly compensation in explaining the impact of
    the raised federal minimum wage on the Au Pair Program.                That is
    so even though the au pair exchange program regulations would
    appear to permit that minimum to vary based on the actual costs
    host families incurred.         Relying on this apparent discrepancy, the
    DOS and the plaintiffs -- though, again, only in passing -- argue
    that these guidance documents indicate that the agency had imposed
    a national, uniform system for au pair compensation.
    But,   the   2007    guidance     is   itself   directed   only   at
    sponsors.   At most, it would suggest that sponsors were obliged to
    enforce a weekly amount of compensation that was higher than what
    the FLSA and its regulations would require that the au pair
    participants be paid.       We thus do not see how that one guidance
    document, insofar as it even comports with the text of the DOS
    regulations themselves, could supply the basis for inferring an
    intent from the Au Pair Program to transform the non-preemptive
    FLSA floor on the wage and hour rights that au pair participants
    have vis-a-vis their host family employers into a preemptive
    federal ceiling on those rights.
    In fact, if we are considering past agency practice, the
    DOS acknowledges that, when litigation first arose to enforce a
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    state wage and hour measure for the benefit of au pair participants
    in 2015, a DOS spokesperson publicly stated that au pair exchange
    program sponsors must "comply with all other applicable federal,
    state,      and   local     laws,   including   any   state     minimum   wage
    requirements."      Lydia DePillis, Au Pairs Provide Cheap Child Care.
    Maybe Illegally Cheap., Wash. Post, Mar. 20, 2015.             With regard to
    communicating these requirements to au pair sponsor agencies,
    moreover, the DOS spokesman went on to say: "The Department has
    been communicating with au pair sponsors to confirm that they are
    aware of their obligations under the regulations -- including with
    respect to host family requirements -- and will continue to do
    so."    Id.17
    We recognize that the DOS asserts that it is not "clear"
    that the agency's public response at that time represented a
    considered view.          We do not suggest otherwise.        But, insofar as
    the agency means to invoke other aspects of its past practice that
    it concedes do not represent the kind of considered agency view
    17
    Although a 2014 version of a State Department informational
    pamphlet, the Wilberforce Pamphlet, stated that all recipients of
    nonimmigrant visas “have the right to be paid the higher amount"
    of the federal or state minimum wages, the State Department took
    out that statement when it revised the pamphlet in 2016. Compare
    U.S. Dep’t of State, 2014 Wilberforce Pamphlet 7 (2014),
    https://internationalservices.ncsu.edu/files/2015/03
    /Wilberforce-Pamphlet.pdf, with U.S. Dep’t of State, 2016
    Wilberforce    Pamphlet    (2016),    https://j1visa.state.gov/wp-
    content/uploads/2017/01/Wilberforce_Pamphlet_October2016.pdf.
    - 77 -
    that merits deference to demonstrate how unthinkable it has always
    been that the Au Pair Program could function if state wage and
    hours laws could be enforced against host families, this aspect of
    the agency's past history at least suggests that the supposedly
    unthinkable was thought.
    The regulatory history does suggest that the au pair
    exchange program regulations were promulgated at a time when it
    may not have been evident that there were independently enforceable
    wage   and   hour   protections    for    domestic     workers   beyond   those
    established by the FLSA itself.              See supra Section III.B.3.a.
    State laws providing such protections are never mentioned by the
    agency.   But, the fact that the agency may not have had those state
    laws in view does not permit us to conclude that the agency must
    therefore    have   preempted     them,   at   least    given    the   sponsor-
    targeting, floor-setting words that the agency chose to use in the
    regulations and what the history underlying those words reveals
    about the agency's focus.         For, while we may assume that the DOS
    would be free to preempt such state laws now by revising the
    regulations, it may not simply ascribe to them, retrospectively,
    a   ceiling-setting    character     that    neither    the   text,    nor   the
    regulatory history, nor even past practice demonstrates that they
    have had.
    - 78 -
    V.
    We come, then, to the plaintiffs' fallback grounds for
    challenging the District Court's ruling.              They contend that,
    insofar   as   we   find   the   Massachusetts    state   laws   not    to   be
    preempted, the District Court erred in denying their motion under
    Rule 59(e) for reconsideration of the District Court's decision on
    the motion to dismiss or, in the alternative, for leave to amend
    their complaint pursuant to Rule 15(a).          We review denials of both
    motions for abuse of discretion.            United States ex rel. Ge v.
    Takeda Pharm. Co., 
    737 F.3d 116
    , 127 (1st Cir. 2013).                  We find
    none.
    The plaintiffs can succeed on a Rule 59(e) motion for
    reconsideration -- relief for which, we have noted, is "granted
    sparingly," -- only if they can show that "the original judgment
    evidenced a manifest error of law, if there is newly discovered
    evidence, or in certain other narrow situations."            Biltcliffe v.
    CitiMortgage, Inc., 
    772 F.3d 925
    , 930 (1st Cir. 2014) (internal
    quotations omitted).       Starting with the first of the motions, we
    note that the plaintiffs premised it on the availability of what
    they deemed "new evidence," which included, among other things, an
    affidavit from Stanley Colvin, a former DOS official, and letters
    from current members of Congress.
    The plaintiffs contend that, in rejecting the motion, it
    was "unreasonable" for the District Court to decline to consider
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    the Colvin affidavit, host family declarations, and letters from
    members of Congress, because of the "persuasive information" that
    they contained.     The plaintiffs further contend that the District
    Court   abused    its   discretion      in   failing   to   do   so    because    it
    "declined to consider documents outside the pleadings in ruling
    on" the motion to dismiss pursuant to Rule 12(b)(6) and relied on
    this rationale for denying the motion for reconsideration.                 As the
    plaintiffs put it, the District Court abused its discretion in
    this regard because it made this decision "without even reviewing
    [the Colvin affidavit] . . . even though the District Court had
    previously suggested at an earlier status conference that the
    parties   could    agree   to    submit      additional     facts     outside    the
    Complaint, and even though the District Court did consider other
    materials outside the pleadings in its decision."
    The    District      Court    did   consider     a    congressionally
    commissioned report from the GAO that the Attorney General cited,
    but which was not in the record, in deciding the motion to dismiss.
    But, that document, as the District Court noted, is publicly
    available and the plaintiffs did not object to its inclusion.                    The
    documents at issue in this challenge, by contrast, were not
    publicly available, and the Attorney General did object to their
    consideration and thus did not agree to their submission.
    The plaintiffs' arguments concerning the denial of their
    request to amend their complaint pursuant to Rule 15(a) are
    - 80 -
    similarly unavailing.    Under that Rule, District Courts "freely
    give leave [to amend the complaint] when justice so requires."
    Fed. R. Civ. P. 15(a).     But, as we have explained, "once [a]
    judgment has been entered, the district court is without power to
    entertain any amendments unless the judgment is set aside."     Deka
    Int'l S.A. v. Genzyme Corp. (In re Genzyme Corp. Secs. Litig.),
    
    754 F.3d 31
    , 46 (1st Cir. 2014).      And here, judgment was entered
    prior to the plaintiffs' motion to amend and, thus, the District
    Court denied that motion on that basis.
    The plaintiffs do contend that the District Court abused
    its discretion in denying this motion for leave to amend by relying
    on our decision in Fisher v. Kadant, 
    589 F.3d 505
    , 509 (1st Cir.
    2009), because there "the plaintiffs had two months between the
    order on the motion to dismiss and entry of judgment." But, Fisher
    did not rely on the time between the order on the motion to dismiss
    and the entry of judgment in reaching its conclusion. See id. at
    509-14.   And, the plaintiffs do not grapple with a series of other
    cases applying Rule 15(a) also without regard for the time between
    the order on the motion to dismiss and the entry of judgment.   See,
    e.g., In re Genzyme, 754 F.3d at 46; Feliciano-Hernández v.
    Pereira-Castillo, 
    663 F.3d 527
    , 538 (1st Cir. 2011).    Thus, we see
    no abuse of discretion by the District Court on this score either.
    VI.
    The judgment of the District Court is affirmed.
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