United States v. Concepcion ( 2021 )


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  •           United States Court of Appeals
    For the First Circuit
    No. 19-2025
    UNITED STATES OF AMERICA,
    Appellee,
    v.
    CARLOS CONCEPCION,
    a/k/a BIG PAPI, a/k/a PAPI,
    Defendant, Appellant.
    APPEAL FROM THE UNITED STATES DISTRICT COURT
    FOR THE DISTRICT OF MASSACHUSETTS
    [Hon. William G. Young, U.S. District Judge]
    Before
    Howard, Chief Judge,
    Selya and Barron, Circuit Judges.
    J. Martin Richey, Assistant Federal Public Defender, for
    appellant.
    Jennifer Hay Zacks, Assistant United States Attorney, with
    whom Andrew E. Lelling, United States Attorney, was on brief, for
    appellee.
    March 15, 2021
    SELYA,    Circuit    Judge.         Defendant-appellant       Carlos
    Concepcion pleaded guilty to possession with intent to distribute
    and distribution of cocaine base (crack cocaine) in 2008.                    The
    following year, the district court sentenced him to a 228-month
    term of immurement.     While the defendant was serving his sentence,
    Congress passed the Fair Sentencing Act, Pub. L. No. 111-220, 
    124 Stat. 2372
    , which reduced the statutory penalties for most federal
    crimes   involving    crack    cocaine    in    an    effort   to    ameliorate
    sentencing disparities between crack cocaine offenses and powdered
    cocaine offenses.
    In 2018, Congress made these changes retroactive through
    the First Step Act, Pub. L. No. 115-391, 
    132 Stat. 5194
    , and the
    defendant moved for resentencing.          The district court denied his
    motion, United States v. Concepcion, No. 07-10197, 
    2019 WL 4804780
    (D. Mass. Oct. 1, 2019), and this timely appeal followed.
    The    defendant    contends    that     the   district   court   was
    obliged to, but did not, update and reevaluate the constellation
    of   sentencing     factors    adumbrated      in    
    18 U.S.C. § 3553
    (a).
    Relatedly, he contends that, pursuant to this obligation, the
    district court should have recalculated his guideline sentencing
    range (GSR) anew under the sentencing guidelines in effect at the
    time of resentencing.1    Even if a recalculation of his GSR was not
    1 It is not clear whether the defendant seeks to have his GSR
    recalculated pursuant to the guidelines in effect at the time he
    - 2 -
    required, he submits, the district court should have given effect
    to guideline changes occurring subsequent to the imposition of his
    original sentence.   Because we have not yet spoken definitively to
    the scope of resentencing under the First Step Act, this appeal
    presents issues of first impression in this circuit. After careful
    consideration, we reject the defendant's asseverational array and
    affirm the district court's order denying resentencing.
    I. BACKGROUND
    We start by rehearsing the relevant facts and the travel
    of the case.     In 2006, federal law enforcement officers in New
    Bedford, Massachusetts, monitored two drug transactions in which
    the defendant participated.   Those transactions, in the aggregate,
    involved the sale of 27.5 grams of crack cocaine.   Warrant-backed
    searches of the defendant's home and car turned up an additional
    186.34 grams of powdered cocaine, two loaded firearms, and many
    rounds of ammunition.
    In due course, a federal grand jury sitting in the
    District of Massachusetts charged the defendant with possessing
    with intent to distribute and distributing five grams or more of
    crack cocaine.    See 
    21 U.S.C. § 841
    (a)(1) (2006).    This charge
    filed his motion for resentencing or, should his motion be granted,
    those in effect at the time of resentencing. As a shorthand, we
    refer in this opinion to the guidelines in effect at the time of
    resentencing. We note, however, that this appeal does not require
    us to explore the choice between these alternatives, and we leave
    the question open.
    - 3 -
    carried a statutory minimum penalty of five years' imprisonment
    and a statutory maximum penalty of forty years' imprisonment.                        See
    
    id.
     § 841(b)(1)(B)(iii).            The government, acting pursuant to 
    21 U.S.C. § 851
    (a)(1), filed an information memorializing that the
    defendant     had    a    prior    felony    drug-offense       conviction,        which
    doubled the mandatory minimum and boosted the maximum available
    sentence to life imprisonment.              See 
    id.
    Although     initially        maintaining     his       innocence,    the
    defendant      eventually         pleaded     guilty      to        the   single-count
    indictment.         The probation department proceeded to prepare a
    presentence investigation report (PSI report).                      After tentatively
    concluding that the defendant had a total offense level of twenty-
    five and should be placed in Criminal History Category (CHC) V,
    the PSI report determined that the defendant qualified as a career
    offender under USSG §4B1.1(a). This determination rested, in part,
    on the fact that the defendant's criminal record included at least
    two   prior    felony      convictions       for   crimes      of    violence    and/or
    controlled substance offenses.              Specifically, his criminal history
    revealed state convictions for distribution of crack cocaine,
    possession     with      intent   to   distribute      powdered       cocaine,     armed
    carjacking, armed robbery, and assault and battery with a dangerous
    weapon.       The career offender designation resulted in a total
    offense level of thirty-four, a CHC of VI, and a GSR of 262 to 327
    months.
    - 4 -
    The district court convened the disposition hearing on
    May 6, 2009.    The court adopted the final guideline calculations
    recommended in the PSI report (including the career offender
    designation).   The defendant argued for a downwardly variant 120-
    month sentence (the mandatory minimum), and the government argued
    for a 262-month sentence (the bottom of the GSR).           The court mulled
    the section 3553(a) factors and considered, among other things,
    the defendant's troubled youth and then-current guideline and
    policy developments.         The court found that a below-the-range
    sentence of 228 months was "sufficient but not greater than
    . . . necessary," and therefore fair and just.              Cf. Kimbrough v.
    United States, 
    552 U.S. 85
    , 111 (2007) (upholding downward variance
    when sentencing court had appropriately considered defendant's
    GSR, defendant's background, and Sentencing Commission's then-
    recent    criticism   of     disparate     treatment   of    crack   cocaine
    offenses).   The defendant appealed, and we summarily affirmed the
    challenged sentence.       See United States v. Concepcion, No. 09-1691
    (1st Cir. Dec. 30, 2009) (unpublished judgment).
    This was far from the end of the matter.            The defendant
    sought collateral review of his sentence through a motion filed
    pursuant to 
    28 U.S.C. § 2255
    .            The district court denied the
    motion.   Little daunted, the defendant — on August 1, 2016 — again
    moved to vacate his sentence under section 2255.               The district
    court treated the motion as an application for leave to file a
    - 5 -
    second or successive section 2255 motion and referred it to this
    court.      See 
    28 U.S.C. § 2255
    (h) (explaining that a second or
    successive motion under section 2255 "must be certified . . . by
    .   .   .   the   appropriate    court   of   appeals").   We   denied   the
    application.       See Concepcion v. United States, No. 16-2209 (1st
    Cir. Apr. 27, 2017) (unpublished judgment).           Mistakenly believing
    that the third time was the charm, the defendant filed yet another
    section 2255 motion.            That motion met a similar fate.          See
    Concepcion v. United States, No. 17-1637 (1st Cir. July 31, 2017)
    (unpublished judgment).
    Nearly two years later, the defendant moved pro se to
    reduce his sentence pursuant to the First Step Act.             See Pub. L.
    No. 115-391, 
    132 Stat. 5194
    .         He argued that the First Step Act,
    by retroactively raising the quantity of crack cocaine required to
    trigger the statutory penalty provision set forth in 
    21 U.S.C. § 841
    (b)(1)(B)(iii) (2018), reduced his statutory maximum sentence
    to thirty years, see 
    21 U.S.C. § 841
    (b)(1)(C), and shrank his GSR
    to 188 to 235 months.       Once counsel was appointed, an additional
    argument was advanced on the defendant's behalf.            This argument
    posited that the defendant no longer qualified as a career offender
    and, thus, should be regarded as having a GSR of fifty-seven to
    seventy-one months.      The government opposed the motion:        although
    it agreed that the defendant was eligible for resentencing under
    the First Step Act, it cited the leniency originally extended by
    - 6 -
    the district court and urged that a reduced sentence be withheld
    as a matter of discretion.
    The district court, in a thoughtful rescript, denied the
    defendant's motion for resentencing.     Concepcion, 
    2019 WL 4804780
    ,
    at *2-6.   This appeal ensued.
    II. ANALYSIS
    The defendant assigns error to the district court's
    denial of his motion for resentencing.      Specifically, he contends
    that in deciding whether to reduce his sentence pursuant to the
    First Step Act, the court was required to evaluate the 
    18 U.S.C. § 3553
    (a) factors anew and that, under sections 3553(a)(4) and
    (5), such a reevaluation entailed the preparation of a new PSI
    report, calculating a new GSR based on the guidelines in effect at
    the time of resentencing.    As a fallback, the defendant contends
    that even if a new GSR calculation was not obligatory, the court
    should have at least considered intervening guideline developments
    as part of its calibration of the other section 3553(a) factors.
    Because the defendant's contentions hinge, in the first instance,
    on the nexus between the First Step Act and the Fair Sentencing
    Act, we turn directly to this nexus.
    In 2010, Congress enacted the Fair Sentencing Act to
    ameliorate   sentencing   disparities    between   similarly   situated
    defendants convicted of drug-trafficking offenses involving crack
    cocaine, on the one hand, and powdered cocaine, on the other hand.
    - 7 -
    See Dorsey v. United States, 567 U.S 260, 263-64 (2012).            As the
    district court determined, this case fits comfortably within that
    paradigm.    See Concepcion, 
    2019 WL 4804780
    , at *1-2.         Prior to the
    passage of the Fair Sentencing Act, the defendant's conviction for
    an offense involving five or more grams of crack cocaine exposed
    him to a statutory sentencing range of five to forty years in
    prison.      See 
    21 U.S.C. § 841
    (b)(1)(B)(iii) (2006).            The Fair
    Sentencing Act increased the amount of crack cocaine needed to
    trigger this penalty range to twenty-eight grams.                 See Fair
    Sentencing Act § 2(a)(2).        This change, however, did not apply
    retroactively.     Consequently, it did not inure to the benefit of
    offenders — like the defendant — who were sentenced before August
    3, 2010.     See Dorsey, 567 U.S. at 280-81.         As a result, the Fair
    Sentencing Act left in place disparate sentences for crack cocaine
    offenses meted out before August 3, 2010.
    Congress sought to remedy this perceived inequity by
    enacting the First Step Act.       Section 404 of the First Step Act
    applies     specified   portions       of   the     Fair   Sentencing    Act
    retroactively to defendants whose sentences became final before
    August 3, 2010.     Specifically, it provides that "[a] court that
    imposed a sentence for a covered offense may . . . impose a reduced
    sentence as if sections 2 and 3 of the Fair Sentencing Act
    . . . were    in   effect   at   the   time   the    covered   offense   was
    committed."     First Step Act § 404(b).          To complete the picture,
    - 8 -
    the First Step Act defines a "covered offense" as "a violation of
    a Federal criminal statute, the statutory penalties for which were
    modified by section 2 or 3 of the Fair Sentencing Act . . . that
    was committed before August 3, 2010."           Id. § 404(a).   Importantly,
    the First Step Act makes pellucid that the decision to impose or
    withhold a reduced sentence is a decision that rests within the
    sound discretion of the district court. See id. § 404(c) ("Nothing
    in this section shall be construed to require a court to reduce
    any sentence pursuant to this section.").
    Seen in this light, the defendant's offense is a covered
    offense within the purview of the First Step Act.                In 2008, he
    pleaded guilty to a violation of 
    21 U.S.C. § 841
    (a).             The offense
    to     which    he   pleaded,   coupled    with   his   prior   felony      drug
    convictions, subjected him to a mandatory minimum term of ten
    years' imprisonment and exposed him to a maximum sentence of up to
    life imprisonment.       See 
    21 U.S.C. § 841
    (b)(1)(B)(iii) (2006).           And
    this statutory sentencing range was materially altered when the
    Fair    Sentencing     Act   increased    the   triggering   amount   for   the
    mandatory minimum penalty to twenty-eight grams.                Taken in the
    ensemble, these developments brought the defendant's case under
    the carapace of the First Step Act.             See United States v. Smith,
    
    954 F.3d 446
    , 450 (1st Cir. 2020) (concluding that violation of 
    21 U.S.C. § 841
    (a)(1) involving crack cocaine is a covered offense
    under First Step Act).
    - 9 -
    The district court recognized that, because the offense
    of conviction was a covered offense, the First Step Act rendered
    the defendant eligible for a sentence reduction.              The defendant
    argues that the court should have gone further:           it should have
    reevaluated the section 3553(a) factors as of the date of the
    motion and commissioned a new PSI report — one reflecting that,
    under the current iteration of the sentencing guidelines, the
    defendant no longer qualifies as a career offender.             In support,
    the defendant says that one of his prior drug convictions has been
    vacated and that emerging case law precludes some of his other
    predicate offenses from being classified as crimes of violence.
    See, e.g., United States v. Kennedy, 
    881 F.3d 14
    , 24 (1st Cir.
    2018)    (holding   that   Massachusetts   conviction   for    assault   and
    battery with dangerous weapon did not qualify as crime of violence
    under Armed Career Criminal Act); United States v. Starks, 
    861 F.3d 306
    , 319 (1st Cir. 2017) (same with respect to Massachusetts
    robbery).2    We proceed to examine this argument.
    2 These cases were decided in light of Johnson v. United
    States, 
    576 U.S. 591
     (2015), which held "that imposing an increased
    sentence under the residual clause of the Armed Career Criminal
    Act violates the Constitution's guarantee of due process." Id. at
    606. Although the defendant was not sentenced as a career offender
    under the Armed Career Criminal Act, the United States Sentencing
    Commission amended the career offender guideline defining "crime
    of violence" by striking that provision's residual clause in
    response to Johnson. See USSG App. C Supp., Amend. 798 (effective
    Nov. 1, 2016); see also USSG §4B1.2(a) (2018).
    - 10 -
    The scope of resentencing under section 404 of the First
    Step Act is a question of statutory interpretation and, thus,
    engenders de novo review.       See Smith, 954 F.3d at 448; United
    States v. Gibbens, 
    25 F.3d 28
    , 32 (1st Cir. 1994).         Although we
    have not previously confronted this question, we have envisioned
    "at least two possibilities."    Smith, 954 F.3d at 452.   A defendant
    "might be eligible for plenary resentencing, in which case his GSR
    would potentially be recalculated under the current version of the
    Sentencing Guidelines Manual . . . or he might be eligible for a
    procedure . . . in which . . . his GSR would remain as it was [when
    he was sentenced] but the district court might nevertheless vary
    downwardly."    Id.   By demanding "at minimum a present day review
    of the section 3553(a) factors" and "a proper calculation of the
    guidelines in effect at the time of resentencing," the defendant
    seeks what amounts to a plenary review of his sentence.          Thus,
    this case brings front and center the question left open in Smith
    and requires us to decide whether a defendant's eligibility for
    First Step Act resentencing entitles him to plenary resentencing.
    Although this is an issue of first impression in this
    circuit, we do not write on a pristine page.    At least five of our
    sister circuits have held, albeit in various contexts, that section
    404 of the First Step Act does not entitle a defendant to plenary
    resentencing.   See United States v. Moore, 
    975 F.3d 84
    , 90-92 (2d
    Cir. 2020); United States v. Denson, 
    963 F.3d 1080
    , 1089 (11th
    - 11 -
    Cir. 2020); United States v. Kelley, 
    962 F.3d 470
    , 471 (9th Cir.
    2020); United States v. Alexander, 
    951 F.3d 706
    , 708 (6th Cir.
    2019); United States v. Hegwood, 
    934 F.3d 414
    , 415 (5th Cir.),
    cert. denied, 
    140 S. Ct. 285
     (2019); cf. United States v. Hamilton,
    
    790 F. App'x 824
    , 826 (7th Cir. 2020) (concluding that "district
    court did not plainly err by reducing [the defendant's] sentence
    without a plenary resentencing").           Four of these courts have
    squarely addressed whether First Step Act resentencing entitles a
    defendant to a reevaluation of his career offender status under
    subsequently amended but non-retroactive guidelines, and all of
    them have held that it does not.        See Moore, 975 F.3d at 90-91;
    Kelley, 962 F.3d at 475-79; United States v. Foreman, 
    958 F.3d 506
    , 509-12 (6th Cir. 2020); Hegwood, 934 F.3d at 417-19.
    This line of authority, though, is not uniform:             four
    circuits have espoused a minority view.          See United States v.
    White, 
    984 F.3d 76
    , 90 (D.C. Cir. 2020); United States v. Easter,
    
    975 F.3d 318
    , 327 (3d Cir. 2020); United States v. Boulding, 
    960 F.3d 774
    , 784 (6th Cir. 2020); United States v. Chambers, 
    956 F.3d 667
    , 668 (4th Cir. 2020).     For example, the Sixth Circuit has held
    that a First Step Act resentencing must "includ[e] an accurate
    calculation   of   the   amended   guidelines   range   at   the   time   of
    resentencing."     Boulding, 960 F.3d at 784.      So, too, the Fourth
    Circuit, concluding (in a two-to-one opinion) that the First Step
    Act requires a present-day recalculation of a defendant's GSR, has
    - 12 -
    held that "any Guidelines error deemed retroactive . . . must be
    corrected in a First Step Act resentencing."      Chambers, 956 F.3d
    at 668.
    Mindful of this divided authority, we begin — as every
    exercise in statutory analysis should begin — with the text of the
    controlling statute (here, the First Step Act).          The statute
    explicitly authorizes a "court that imposed a sentence for a
    covered offense" to "impose a reduced sentence as if sections 2
    and 3 of the Fair Sentencing Act of 2010 were in effect at the
    time the covered offense was committed."     First Step Act § 404(b)
    (emphasis supplied).   That the First Step Act takes only sections
    2 and 3 of the Fair Sentencing Act back in time, stipulating that
    a new sentence shall be meted out "as if" those sections (and only
    those sections) were in effect when the defendant committed the
    covered offense, is a compelling indication that Congress did not
    intend that other sections of the Fair Sentencing Act are to apply
    retroactively.   See Kelley, 962 F.3d at 475; Hegwood, 934 F.3d at
    418.
    We add, moreover, that       section 404(b)   conspicuously
    constrains a sentencing court's list of newly applicable laws at
    a resentencing hearing to only the Fair Sentencing Act.      Nothing
    in the First Step Act invites the district court to apply changes
    in the law external to the Fair Sentencing Act.    See United States
    v. Smith, 
    958 F.3d 494
    , 498 (6th Cir. 2020) (observing that First
    - 13 -
    Step Act only provides "limited, discretionary authorization to
    impose a reduced sentence" which is "inconsistent with a plenary
    resentencing" (quoting Hegwood, 934 F.3d at 418)); Alexander, 951
    F.3d at 708 (similar).      As the Kelley court explained, the First
    Step Act "authorizes the district court to consider the state of
    the law at the time the defendant committed the offense, and change
    only one variable:    the addition of sections 2 and 3 of the Fair
    Sentencing Act as part of the legal landscape."           962 F.3d at 475.
    The   consideration   of    Amendment     798   and    current   sentencing
    guidelines, as the defendant envisions, goes beyond the limits of
    this authorization.
    The fact that the First Step Act vests a district court
    with wide discretion about whether to reduce a defendant's sentence
    for a covered offense, see First Step Act § 404(b); id. § 404(c),
    cuts in the same direction.        That Congress saw fit to afford
    district courts such       wide discretion is in tension with the
    defendant's argument that      the court was          obliged to follow a
    specific procedure — a full reevaluation of the section 3553(a)
    factors and a mandatory recalculation of the defendant's GSR under
    current guidelines.
    Along the same line, it is clear to us — and our
    dissenting brother agrees — that a First Step Act resentencing
    constitutes only a modification of an imposed term of imprisonment.
    Further Congressional circumscriptions on resentencing apply in
    - 14 -
    such cases, and those circumscriptions underscore the limited and
    discretionary nature of the authorization afforded to sentencing
    courts under the First Step Act.   See Smith, 958 F.3d at 498.   As
    a general matter, a final judgment in a criminal case may not be
    revisited by the sentencing court.     See 
    18 U.S.C. § 3582
    (b)-(c);
    see also Dillon v. United States, 
    560 U.S. 817
    , 824 (2010).      Of
    course, this rule — like many general rules — admits of certain
    exceptions.   But in the absence of an applicable exception, "[a]
    court may not modify a term of imprisonment." 
    18 U.S.C. § 3582
    (c).
    Two such exceptions are relevant here.   Under the first,
    "the court may modify an imposed term of imprisonment to the extent
    . . . expressly permitted by statute." 
    Id.
     § 3582(c)(1)(B). Under
    the second,
    "in the case of a defendant who has been
    sentenced to a term of imprisonment based on
    a sentencing range that has subsequently been
    lowered by the Sentencing Commission pursuant
    to 28 U.S.C. [§] 994(o), . . . the court may
    reduce the term of imprisonment, after
    considering the factors set forth in section
    3553(a)   to  the   extent   that  they   are
    applicable, if such a reduction is consistent
    with applicable policy statements issued by
    the Sentencing Commission."
    Id. § 3582(c)(2).
    Because section 2 of the Fair Sentencing Act only reduced
    the statutory penalties applicable to defendants convicted of
    crack cocaine offenses, and did not address sentences already
    imposed, retroactive modification of sentences under the Fair
    - 15 -
    Sentencing Act prior to the First Step Act could be sought only
    "by reference to reductions in the sentencing range."         United
    States v. Wirsing, 
    943 F.3d 175
    , 184 (4th Cir. 2019).    And because
    those reductions were made "by the Sentencing Commission," section
    3582(c)(2) constituted the appropriate exception to the finality
    of a sentence for those retroactive modification requests.    Id. at
    184-85.
    A First Step Act motion, by contrast, is grounded in the
    Act's explicit authorization for a sentencing court to reduce a
    sentence, rather than on actions of the Sentencing Commission.
    For this reason, the appropriate framework for the evaluation of
    a § 404(b) motion is found in § 3582(c)(1)(B).      See id.; United
    States v. Holloway, 
    956 F.3d 660
    , 665-66 (2d Cir. 2020) ("A First
    Step Act motion . . . is not properly evaluated under 
    18 U.S.C. § 3582
    (c)(2). . . . [S]uch a motion falls within the scope of
    § 3582(c)(1)(B).").   Accordingly, a sentencing court evaluating a
    section 404(b) motion may modify a sentence only to the extent
    "expressly permitted" by the First Step Act.    See § 3582(c)(1)(B).
    This exception is narrow:     by its terms, the First Step
    Act allows only "a specific type of sentence reduction."         See
    Kelley, 962 F.3d at 477.   The permission granted in section 404(b)
    is only permission to "impose a reduced sentence as if sections 2
    and 3 of the Fair Sentencing Act . . . were in effect."     And this
    type of sentence reduction is wholly discretionary.       See First
    - 16 -
    Step Act § 404(b)-(c).            It follows, we think, that mandatory
    enforcement of intervening changes in the law, not encompassed by
    sections 2 and 3 of the Fair Sentencing Act — in this instance,
    Amendment 798 and any newly updated guidelines — would fall outside
    the compass of the leave Congress granted under the First Step
    Act.   Simply put, a First Step Act resentencing is not the correct
    vehicle through which a defendant may demand the benefits of
    emerging legal developments unrelated to sections 2 and 3 of the
    Fair Sentencing Act — and Congress has prohibited the courts from
    holding otherwise.     See 
    18 U.S.C. § 3582
    (c).
    In   addition    to    these      statutory    limitations    on    a
    sentencing court's authority, we find persuasive the government's
    suggestion that a mechanical application of intervening changes in
    the law would lead to anomalous results.               Congress enacted the
    Fair Sentencing Act to correct the unequal treatment of crack
    cocaine offenses as compared to powdered cocaine offenses.                      To
    interpret section 404(b) to allow certain crack cocaine offenders
    to   avail   themselves      of   case   law    unrelated   to   crack    cocaine
    sentencing disparities would not create a level playing field but,
    rather, would put defendants convicted of crack cocaine offenses
    in a more advantageous position than defendants convicted of
    powdered cocaine offenses.          Indeed, such an interpretation would
    put crack cocaine defendants who had committed covered offenses in
    - 17 -
    a   more   advantageous   position    than      other   criminal   defendants
    generally.    See Kelley, 962 F.3d at 478.
    We discern    nothing in the text of either the Fair
    Sentencing Act or the First Step Act that warrants a conclusion
    that Congress intended to replace one set of sentencing disparities
    with another.     It would, therefore, be an exercise in judicial
    hubris to transmogrify a motion for resentencing under the First
    Step Act into an exclusive backstreet permitting the free-wheeling
    correction of putative errors in a defendant's GSR anytime that
    the guidelines change.         See Chambers, 956 F.3d at 676 (Rushing,
    J., dissenting) ("Congress's concern in Section 404 was to extend
    the cocaine sentencing provisions of the Fair Sentencing Act
    retroactively,     not    to    provide     a    general    opportunity   to
    collaterally attack a final sentence.").
    In a further effort to broaden the scope of First Step
    Act resentencing, the defendant invokes section 404(b)'s statement
    that a court may "impose a reduced sentence as if sections 2 and
    3 . . . were in effect at the time the covered offense was
    committed."     First Step Act § 404(b).          Focusing with laser-like
    intensity on the word "impose," the defendant insists that this
    word choice evinces congressional intent that First Step Act
    defendants be resentenced under "the familiar . . . framework" of
    
    18 U.S.C. § 3553
    (a).      This word choice is critically important,
    the defendant says, because the power to "impose" a sentence is
    - 18 -
    more expansive than the power either to "modify" a sentence or to
    "reduce" a sentence.     Similarly, he gives weight to the fact that
    the participle of "impose" is used in section 3553(a)'s enumeration
    of "factors to be considered in imposing a sentence."           We find
    this argument unconvincing.
    At the outset, we note that the defendant's tunnel-
    vision reading of the word "impose" overlooks the express limiting
    language of the First Step Act:      the "as if" clause.    That clause
    permits a sentencing court to apply only sections 2 and 3 of the
    Fair Sentencing Act — and no more.        See Moore, 975 F.3d at 91
    (explaining that "the First Step Act does not simply authorize a
    district court to 'impose a sentence' [but] authorizes the court
    to do so subject to the 'as if' clause").             The defendant's
    selective rendition of the First Step Act sidesteps this plain
    statutory language.
    What is more, reading the word "impose" in isolation
    ignores the fact that the Act permits only a sentence reduction.
    First   Step   Act §   404(b)-(c).   Language   has   its   limits   and,
    situating the word "impose" in context, we are skeptical that a
    meaningful difference exists between "imposing" a reduced sentence
    and "reducing" a sentence.     In all events, no such difference has
    been articulated here. Viewed objectively, the fact that the First
    Step Act allows only a sentence reduction strongly suggests that
    the act does not authorize what would effectively be plenary
    - 19 -
    resentencing.     See    Alexander,     951   F.3d    at    708    (noting   that
    "authorization to impose a reduced sentence is inconsistent with
    a plenary resentencing"); cf. Dillon, 
    560 U.S. at 831
     (concluding
    that 
    18 U.S.C. § 3582
    (c)(2) "does not authorize a resentencing"
    but "[i]nstead . . . permits a sentence reduction").
    We add a coda.    The defendant's entreaty that we mandate
    a fresh evaluation of the section 3553(a) factors would, if
    honored, impermissibly cabin the discretion that the First Step
    Act vests in the district court.         It is to that, at an original
    sentencing, the district court, "in determining whether to impose
    a term of imprisonment shall consider the factors set forth in
    section 3553(a)."       
    18 U.S.C. § 3582
    (a).         By contrast, though, a
    sentence    reduction     under   the    First       Step    Act     is    wholly
    discretionary.   See First Step Act § 404(b)-(c).            In our view, the
    wide discretion inherent in First Step Act resentencing undercuts
    the defendant's textual argument.        See United States v. Moore, 
    963 F.3d 725
    , 727-28 (8th Cir. 2020) (rejecting argument that statutory
    use   of   "impose"   requires    consideration        of    section      3553(a)
    factors); Kelley, 962 F.3d at 477-78 (same); Foreman, 958 F.3d at
    510-12 (same).
    Nor need we linger long over the defendant's contention
    that our construction of the First Step Act is at odds with 
    18 U.S.C. § 3553
    (a).     At the time of resentencing, a district court
    must place itself back at the date of the offense, altering the
    - 20 -
    legal landscape only by resort to sections 2 and 3 of the Fair
    Sentencing Act. See Hegwood, 934 F.3d at 418. This counterfactual
    exercise does not undo the sentencing court's original calibration
    of the section 3553(a) factors.         See id. at 418-19 (explaining
    that resentencing under the First Step Act "is being conducted as
    if all the conditions for the original sentencing were again in
    place with the one exception").    Because the text and structure of
    the First Step Act do not support plenary resentencing, there is
    no principled way that we can find reassessment of the section
    3553(a) factors mandatory.
    The short of it is that the scope of a First Step Act
    resentencing is more circumscribed than the defendant envisions.
    Application of the First Step Act, which vests great discretion in
    the district court, raises two questions:          the binary question of
    whether a defendant should be resentenced and the conditional
    question of what that new sentence should be.            See Denson, 963
    F.3d at 1087 ("The First Step Act leaves the choice of whether to
    resentence and to what extent to the district court's sound
    discretion.").     Fairly viewed, such a proceeding entails a two-
    step inquiry by the district court.          At the first step, the
    district   court   should   determine    whether    resentencing   of   an
    eligible defendant is appropriate under the circumstances of the
    particular case.      At this step, though, the district court's
    discretion is cabined by the limited permission that Congress saw
    - 21 -
    fit to grant under section 404(b).               Consequently, the district
    court must place itself at the time of the original sentencing and
    keep the then-applicable legal landscape intact, save only for the
    changes specifically authorized by sections 2 and 3 of the Fair
    Sentencing Act.     Cf. Kelley, 962 F.3d at 475 (adopting a two-step
    inquiry under which a district court should first "place itself in
    the counterfactual situation where all the applicable laws that
    existed at the time the covered offense was committed are in place,
    making only the changes required by sections 2 and 3 of the Fair
    Sentencing Act").          The court must then determine whether the
    defendant should be resentenced.            Because section 3582(c)(1)(B)
    restricts    a   sentencing     court's        "permi[ssion]"     to   modify    a
    sentence, a district court's decision to permit a modification
    must be based solely on the changes that sections 2 and 3 of the
    Fair   Sentencing    Act    require    to   be   made   with    respect   to    the
    defendant's original GSR.        See Hegwood, 934 F.3d at 418 (holding
    that adjustment of defendant's GSR "'as if' the lower drug offense
    sentences were in effect at the time of the commission of the
    offense . . . is the only explicit basis . . . for a change in the
    sentencing").       If that determination is in the negative, the
    inquiry ends and any sentence reduction must be denied.
    If, however, the district court's determination is in
    the affirmative, it may impose a reduced sentence under step two
    of the inquiry.     It is at this step that a district court may, in
    - 22 -
    its discretion, consider other factors relevant to fashioning a
    new sentence. See Foreman, 958 F.3d at 513 (explaining that "First
    Step Act imposes no additional constraints on a district court's
    discretion once it determines the statutory and Guidelines ranges
    'as if' the Fair Sentencing Act has been in effect before 2010").
    Specifically, the discretion that the First Step Act vests in the
    district court leads to the logical conclusion — which we endorse
    — that "a district court may, but need not, consider section 3553
    factors" in a reduction in sentence.          Moore, 963 F.3d at 727.     When
    mulling these factors, the court may choose to consider conduct
    that occurred between the date of the original sentencing and the
    date of resentencing.        See United States v. Hudson, 
    967 F.3d 605
    ,
    612; Chambers, 956 F.3d at 674; United States v. Jackson, 
    945 F.3d 315
    , 322 n.7 (5th Cir. 2019).
    So,   too,    the   district    court   may   consider    guideline
    changes,   whether      or   not   made   retroactive    by   the   Sentencing
    Commission, once it reaches the second step of the resentencing
    pavane.    After all, a district court may take into consideration
    any relevant factors (other than those specifically proscribed),
    including current guidelines, when deciding to what extent a
    defendant should be granted relief under the First Step Act.3              See
    3 The scope of this discretion is consistent with our case
    law allowing sentencing courts to consider intervening guideline
    amendments in other contexts. See, e.g., United States v. Ahrendt,
    
    560 F.3d 69
    , 78-80 (1st Cir. 2009) (remanding for discretionary
    - 23 -
    Foreman, 958 F.3d at 513; see also United States v. Harris, 
    960 F.3d 1103
    , 1106 (8th Cir. 2020); Smith, 954 F.3d at 452 n.8.                 It
    follows, we think, that a district court, upon electing to fashion
    a reduced sentence pursuant to the First Step Act, may in its
    discretion order the preparation of a new PSI report.                 Such an
    updated PSI report may contain a revised GSR, based in part upon
    subsequent, non-retroactive guideline amendments.              We emphasize,
    though, that this discretion is a two-sided coin, and the district
    court may choose to forgo a new PSI report entirely.
    Our dissenting brother disagrees in part:           he diverges
    from our view in his interpretation of the scope of the discretion
    that a resentencing court possesses when deciding whether to
    resentence a defendant under step one. In his view, the discretion
    that our opinion affords a district court under step two should
    extend to step one such that, in deciding whether resentencing is
    appropriate, the district court should be able to consider post-
    sentencing    information.      The   main   support     for   the   dissent's
    proposition is that section 3582(c)(2), the vehicle through which
    defendants    requested   a    retroactive    application      of    the   Fair
    Sentencing Act prior to the First Step Act, expressly allows a
    court   to   consider   such   information    in   its    determination     of
    resentencing based on non-retroactive guideline amendment); United
    States v. Godin, 
    522 F.3d 133
    , 136 (1st Cir. 2008) (per curiam)
    (similar).
    - 24 -
    "whether" to sentence a defendant.                See 19 USSG §1B1.10 cmt.
    n.1(B)(iii) ("The court may consider post-sentencing conduct of
    the defendant that occurred after imposition of the term of
    imprisonment in determining:          (I) whether a reduction in the
    defendant's term of imprisonment is warranted; and (II) the extent
    of such reduction . . . .").        Nevertheless, our dissenting brother
    argues that, in order to grant post-First-Step-Act defendants an
    opportunity for relief "roughly equivalent" to that afforded to
    previous defendants, the discretion to consider such information
    should apply in section 404(b) proceedings.             Post at 60.
    But we have determined — and our dissenting brother does
    not dispute — that section 3582(c)(1)(B), not section 3582(c)(2),
    governs section 404(b) proceedings. See supra at 16. Thus, "there
    is   no   reason     to   suppose     that    motions     brought     pursuant
    to   3582(c)(1)(B) are subject to the restrictions particular to
    § 3582(c)(2),   which     are   grounded     in   the   text   of   the   latter
    statute."    Wirsing, 943 F.3d at 185.        Although the application of
    section 3582(c)(2) is expressly required to comport with section
    1B1.10, neither section 3582(c)(1)(B) nor section 1B1.10 requires
    a sentence modification under section 3582(c)(1)(B) "to comport
    with U.S.S.G. § 1B1.10 or any other policy statement."               Holloway,
    
    956 F.3d 666
    .      It follows that "the defendant's eligibility turns
    only on the statutory criteria" in section 3582(c)(1)(B) and the
    First Step Act.     
    Id.
    - 25 -
    In    fact,     the     deficiencies   in     pre-First-Step-Act
    resentencing that our dissenting brother identifies were wholly
    ameliorated by the removal of the restrictions that section 1B1.10
    imposed on section 3582(c)(2) proceedings.                Prior to the First
    Step Act, a defendant was not eligible for a sentence reduction if
    the sentencing amendments introduced by the Fair Sentencing Act
    did not have the effect of lowering the defendant's GSR or if the
    defendant had been originally sentenced as a career offender.
    United States v. Stewart, 
    964 F.3d 433
    , 436 (5th Cir. 2020).                   Both
    of these categories of sentence-reduction denials emerged a result
    of section 1B1.10 restrictions on section 3582(c)(2) proceedings.
    See 
    id.
          In explicitly authorizing sentence modifications in the
    First Step Act, Congress purposefully excised reductions related
    to the Fair Sentencing Act from the realm of section 3582(c)(2),
    thereby relieving section 404(b) proceedings from section 1B1.10
    restrictions.          See Holloway, 956 F.3d at 667 ("A defendant's
    eligibility for a reduced term of imprisonment under Section 404
    of the First Step Act is not governed by 
    18 U.S.C. § 3582
    (c)(2),
    and   thus    a    district   court    considering   such   a   motion    is   not
    constrained by U.S.S.G. § 1B1.10[]."); 
    18 U.S.C. § 3582
    (c)(1)(B).
    The inference that certain portions of section 3582(c)(2) should
    animate      section    404(b)      proceedings   that   take   place    under   a
    different statutory provision simply does not follow.
    - 26 -
    It is also not clear why only certain portions (as
    opposed to all) of the limitations applicable to section 3582(c)(2)
    should pertain to First Step Act resentencings.          As our dissenting
    brother points out, in a court's determination of whether a
    defendant should be resentenced under section 3582(c)(2), the
    consideration of post-sentencing information is permissive.              See
    Post at 60; see also 19 USSG §1B1.10 cmt. n.1(B)(iii).            In that
    same determination, though, the consideration of section 3553(a)
    factors is obligatory.     See 19 USSG §1B1.10 cmt. n.1(B)(i).           But
    the dissent does not argue that such an obligation applies to
    section 404(b) proceedings.      The same is true, for example, of the
    section 1B1.10 prohibition on sentence reductions in which an
    amendment does not lower a defendant's GSR.         Even though nothing
    in the First Step Act disavows this limitation, our dissenting
    brother infers that this specific provision does not apply to
    section 404(b) proceedings.       Absent a Congressional directive to
    apply limitations on relief expressly applicable to one statutory
    provision to another statutory provision, we see no justification
    for   picking   and   choosing    from   the   section   1B1.10   list    of
    limitations.
    We make one final observation:           there is not much
    daylight between the position that we take and the position taken
    by our dissenting brother.       Indeed, the only defendants who would
    be denied a sentence reduction under our framework but who would
    - 27 -
    be successful under our dissenting brother's vision are those
    defendants for whom the Fair Sentencing Act was alone insufficient
    to justify a reduction.           This result not only comports with, but
    also is mandated by, the applicable statutory restrictions.
    The sole remaining issue is whether the district court
    abused    its   discretion     by    denying     the   defendant's      motion   for
    resentencing.      "An abuse of discretion 'occurs when a material
    factor deserving significant weight is ignored, when an improper
    factor is relied upon, or when all proper and no improper factors
    are assessed, but the court makes a serious mistake in weighing
    them.'"    United States v. Soto-Beníquez, 
    356 F.3d 1
    , 30 (1st Cir.
    2003) (quoting Indep. Oil & Chem. Workers, Inc. v. Procter & Gamble
    Mfg. Co., 
    864 F.2d 927
    , 929 (1st Cir. 1988)).
    In this instance, the district court carefully analyzed
    the   First     Step    Act   and    its   application    to     the    defendant's
    situation.       It concluded that the defendant was eligible for
    resentencing      and    focused      on   whether     resentencing      would    be
    appropriate as a matter of discretion.             Deciding that resentencing
    was not warranted, the court stressed its initial leniency.                       It
    made particular note that the downwardly variant sentence it had
    imposed in 2009 was within the new GSR dictated by the provisions
    of the Fair Sentencing Act.            The court proceeded to consider the
    amended   career       offender     guideline,    noted   that    the    Sentencing
    Commission had declined to make it retroactive, and decided not to
    - 28 -
    pantomime it as a matter of discretion.              Summing up, the court
    observed that if the defendant "came before the Court today and
    the   Court    considered   only    the   changes    in   law   that   the   Fair
    Sentencing      Act   enacted,     his    sentence   would      be   the   same."
    Consistent with this observation, the court concluded that the
    original 228-month sentence was "fair and just" in 2009 and
    "remains so today."
    We discern nothing resembling a misuse of the sentencing
    court's discretion.      The court weighed the proper mix of factors,
    considered everything of consequence, and made a judgment that was
    both reasoned and reasonable.            That judgment was well within the
    encincture of the court's discretion.           No more was exigible.
    III. CONCLUSION
    We need go no further. For the reasons elucidated above,
    the judgment of the district court is
    Affirmed.
    -Dissenting Opinion Follows-
    - 29 -
    BARRON, Circuit Judge, dissenting.                      The majority finds
    no abuse of discretion in this case.                  But it is a classic abuse of
    discretion     for      a    district       court    to   decline    to    exercise       the
    discretion       that       it   legally     possesses      because       it    mistakenly
    believes that it lacks that discretion as a matter of law.                              In my
    view,   that     is     exactly      what    happened     here   when,         upon    Carlos
    Concepcion's request for a sentence reduction pursuant to § 404(b)
    of the First Step Act, the District Court declined to give any
    consideration to the favorable intervening change to the career
    offender Guideline that the United States Sentencing Commission
    had made since that Guideline had been applied at his original
    sentencing proceeding.               See U.S.S.G. app. C supp., amend. 798
    (eliminating the residual clause from the "crime of violence"
    definition at U.S.S.G. § 4B1.2(a)).                   I thus am convinced that we
    must    vacate    and       remand    the     District     Court's     ruling         denying
    Concepcion the relief that he seeks pursuant to § 404(b).
    To explain my reasoning, it is necessary to pan out from
    Concepcion's particular case.                  This broader perspective reveals
    not merely the problem with the District Court's ruling on this
    record but also where, in my view, the majority has erred more
    generally in construing § 404(b), which states:                           "A court that
    imposed a sentence for a covered offense may . . . impose a reduced
    sentence as if sections 2 and 3 of the Fair Sentencing Act of 2010
    (Public Law 111-220; 
    124 Stat. 2372
    ) were in effect at the time
    - 30 -
    the covered offense was committed."    First Step Act of 2018, Pub.
    L. No. 115-391, § 404(b), 
    132 Stat. 5194
    , 5222.4
    Through this provision of the First Step Act, Congress
    addressed what had been one of the most glaring inequities in our
    highly punitive federal sentencing framework -- the substantially
    disparate treatment, under both statutory law and the United States
    Sentencing Commission's Guidelines, accorded offenses involving
    crack cocaine relative to those involving powder cocaine.   Section
    404(b) mitigates that inequity by making retroactive the otherwise
    prospective-only Fair Sentencing Act, which Congress enacted to
    lessen that disparate treatment.
    Given the remedial nature of this legislative effort, it
    is a mistake in my view to attribute to Congress an intention to
    constrain district courts from exercising the kind of discretion
    under this provision that they typically may exercise when they
    have been authorized to rectify sentences that time has shown to
    have been unduly harsh.    Cf. 
    18 U.S.C. § 3582
    (c)(2) (permitting
    sentence reductions for defendants whose sentences were "based on
    a sentencing range that has subsequently been lowered by the
    Sentencing Commission").   Yet, as I will explain, the majority's
    4 Section 404(a) of the First Step Act provides the class of
    offenses -- "covered offenses" -- for which the relief provided
    for in § 404(b) may be sought. Section 404(c) places limitations,
    not relevant here, on circumstances in which relief may be sought
    and also makes clear that a district court is not required to
    reduce any sentence under § 404(b).
    - 31 -
    construction of § 404(b), by limiting district courts' ability to
    take account of intervening developments (beyond the retroactive
    application of the Fair Sentencing Act that § 404(b) itself brings
    about), will have that precise consequence in certain important
    respects.
    I begin by describing in greater detail the particular
    questions about the meaning of § 404(b) that this appeal requires
    us to resolve.       I then describe how the majority answers them and
    why   I   conclude    that       certain   of   those   answers    are     mistaken.
    Finally, I explain why in my view the District Court's ruling here
    cannot be sustained.
    I.
    District        courts     enjoy     substantial      discretion        in
    selecting a defendant's sentence.               True, they must set it within
    the   prescribed      statutory       maximum     and   minimum     sentence       (if
    applicable), and they must do so after properly calculating the
    range for the sentence that the United States Sentencing Commission
    recommends through the Guidelines that it promulgates.                        But, at
    least in the original sentencing proceeding, a district court need
    not set the sentence at any particular point within either range
    -- or, it bears mention, within the range at all in the case of
    the Guidelines Sentencing Range ("GSR").
    Questions       do    necessarily     arise,      though,    as   to   the
    considerations       that    may     inform     both    the     district      court's
    - 32 -
    determination of the sentence once the applicable sentencing range
    has been identified and the calculation of the range itself.                And
    these questions arise as much in a proceeding to revisit a sentence
    already imposed (such as on remand from a direct appeal or in a
    proceeding to modify under 
    18 U.S.C. § 3582
    (c)(2)) as they do in
    a proceeding to impose a sentence for the first time.
    One factor that bears on these considerations is the
    focus of our concern in Concepcion's case and that factor is
    temporal in nature.    It concerns the point in time after the
    underlying offense has been committed at which the clock stops,
    such that the district court is then barred from giving weight in
    the   defendant's   sentencing      proceeding        to    any   subsequent
    developments (whether factual, such as post-offense conduct by the
    defendant, or legal, such as amendments to the Guidelines that the
    Commission may have made).
    The   resolution   of    this    temporal    choice     may    matter
    greatly to the outcome of the sentencing proceeding.                    It will
    affect not only the ingredients that the district court may rely
    on in calculating the GSR that it will use in that proceeding but
    also the ingredients that it then may rely on in deciding, based
    off of that GSR, the sentence itself.
    In the context of the original sentencing proceeding, it
    is relatively clear that the clock stops in most respects only
    when the sentencing proceeding itself begins.              Thus, barring any
    - 33 -
    ex post facto concerns, the district court must use the Guidelines
    in effect at the time of that sentencing proceeding -- rather than,
    say, those in effect at the time the defendant committed the
    offense -- to calculate the GSR that will serve as the benchmark
    for the sentence to be imposed at that proceeding.               See David v.
    United States, 
    134 F.3d 470
    , 475 (1st Cir. 1998); see also Gall v.
    United States, 
    552 U.S. 38
    , 50 (2007).              Similarly, when setting
    both the GSR and the actual length of the sentence in relation to
    that   range   in   such   an    original     sentencing    proceeding,     the
    sentencing judge may consider any other pertinent developments
    (including factual ones) that have occurred up to the moment of
    the sentencing.     See 
    18 U.S.C. § 3553
    (a); see also, e.g., United
    States v. Jordan, 
    549 F.3d 57
    , 61 (1st Cir. 2008).
    In the context of revisiting proceedings, it also is
    clear that the clock does not stop at the time the defendant
    committed the underlying offense.            But, there necessarily arises
    in that context this new temporal choice:                  Is the sentencing
    proceeding that stops that clock the one that was held to impose
    the original sentence or the one that is being held thereafter to
    revisit it?
    Concepcion's      appeal    requires     that    we   answer    that
    specific question of timing and that we do so in the particular
    context   of   proceedings      that   are   held   pursuant     to   § 404(b).
    Concepcion contends that the District Court abused its discretion
    - 34 -
    in his case under § 404(b) precisely because it stopped the clock
    at the time of his original sentencing proceeding and thus refused
    to consider at his § 404(b) proceeding subsequent developments
    (both legal, like the amendment to the career offender Guideline
    mentioned above, but also factual) that he contends pointed in
    favor of reducing his sentence.          He further contends that the
    District   Court's   refusal      to     consider   those    intervening
    developments   prejudiced   his    ability   to   receive   the   sentence
    reduction that he contends that he was due under that provision,
    such that the ruling denying him relief under § 404(b) must be
    vacated and remanded.
    II.
    Having isolated the precise issue before us -- and the
    temporal nature of it -- how should we go about resolving it?           As
    I will explain, the answer does not exactly leap off the pages of
    the statute book.
    Section 404(b), by its plain terms, does make clear --
    through its use of the word "reduced" -- that it is authorizing a
    district court to adjust a sentence that has already been imposed
    rather than to impose one anew.            And, in that respect, the
    provision is best read to be authorizing a revisiting proceeding,
    notwithstanding the text's use of the word "impose."
    In addition, § 404(b) makes clear that the district
    court must revisit the original sentence in a counterfactual
    - 35 -
    manner.        As the text states, in deciding to "impose a reduced
    sentence," the district court must proceed "as if" the Fair
    Sentencing Act had been in effect when the underlying offense was
    committed.
    And, the text of § 404(b) also makes perfectly clear
    still     one    more    thing   that    is   relevant     to   our    inquiry.    It
    establishes that the district court will be making the reduction
    decision in the here and now and thus, necessarily, at a time when
    it   is   at     least    possible      for   it    to   know   of    post-sentencing
    developments beyond the one singled out in the "as if" clause.
    After all, at that earlier time, those developments -- like the
    mandate to retroactively apply the Fair Sentencing Act itself --
    had not yet occurred.
    But, § 404(b) is more cryptic than clear when it comes
    to the following additional question of timing that it necessarily
    also prompts:            Is the district court in making the reduction
    decision in the here and now supposed to blind itself to the
    present state of the world beyond the fact of the existence of
    that new mandate imposed by the "as if" clause?                      And, the text is
    similarly hard to decipher when it comes to related questions that
    necessarily arise insofar as the district court may take that
    broader     peek     at    the   present       in    making     such    a   reduction
    determination, such as:            What is the extent of the present-day
    - 36 -
    knowledge that it may draw upon and for what purposes may it do
    so?
    Is the text saying to the district court that it must go
    back in time to the moment of the original sentencing proceeding,
    make the one alteration to that prior state of the world that the
    "as if" clause compels, and then make the reduction decision
    without accounting for what is now also known?              Is it saying
    instead that the district court should simply be exercising the
    same type of discretion to reduce the sentence at hand that it
    ordinarily has in revisiting a sentence already imposed based on
    some change in the law, such as in a run-of-the-mill modification
    proceeding or on a remand from a direct appeal?           Or, is § 404(b)
    saying   instead   something   distinct   from   either    of   those   two
    positions and, if so, what?
    In my view, one could stare at the text of § 404(b) all
    day long looking for answers to those questions and not find them.
    It is only by placing that text in the context of the overall
    federal sentencing framework in which it is embedded that it is
    possible to discern answers to them.        In what follows, then, I
    explain what supplies that context for me and what answers emerge
    from it.    But, it helps first to set forth more fully how the
    majority reads § 404(b) to answer those same questions, as doing
    so will make it clearer both why and how I diverge from its
    approach.
    - 37 -
    A.
    The majority reads § 404(b) to require the district
    court to engage in a two-step inquiry once it determines that the
    defendant was originally sentenced for an offense that is covered
    by that provision.      Those two steps are to be carried out --
    temporally speaking -- as follows.
    The   first   step   of   this   inquiry,   according   to   the
    majority, requires the district court to make a gating judgment in
    which it must ask:      Is any reduction in the original sentence
    appropriate at all?     And, according to the majority, the district
    court in answering that question must set aside a presentist
    mindset and transport itself back in time to the moment of the
    original sentencing proceeding.
    Then, having engaged in that time travel, under the
    majority's approach to this first step of the inquiry, the district
    court, in keeping with § 404(b)'s "as if" clause, must make just
    one adjustment to the state of the world as it then existed.            It
    must proceed at the § 404(b) proceeding "as if" the Fair Sentencing
    Act had been in effect at the time the defendant committed the
    underlying offense.
    As a result, under the majority's approach, the district
    court at this first step of the inquiry must alter the GSR that
    applied at the defendant's original sentencing proceeding -- based
    as it necessarily was on the Guidelines that were in effect at
    - 38 -
    that earlier time.   Or, at least, it must do so in accord with any
    alteration in the then-applicable statutory sentencing range that
    would be required by the retroactive application of the relevant
    provisions of the Fair Sentencing Act that § 404(b) itself brings
    about.
    Finally, after having made that one adjustment to the
    world as it was back then, the district court on the majority's
    view must go on at this first step of the § 404(b) inquiry to make
    the critical gating determination.           In other words, to complete
    the first step, the district court must decide, based on only the
    inputs thus far described, whether to reduce the defendant's
    original sentence given that newly adjusted range.
    The   majority    does    conclude    that   a   district    court
    conducting a § 404(b) proceeding is not so temporally constrained
    once it arrives at the second step of the two-step inquiry.                 At
    that second step, according to the majority, the district court
    may take account of what it could not at step one -- intervening
    factual   developments,     such    as   post-sentencing    conduct    by   the
    defendant, and intervening legal developments, such as amendments
    to the Guidelines that are favorable to the defendant's cause,
    whether or not they are themselves retroactive.
    The district court's sole temporal constraint at this
    second step, then, is relatively minimal.          It is implicit in the
    majority's   approach     that,     in   considering    those   intervening
    - 39 -
    developments -- whether factual or legal -- the district court at
    this second step must use the GSR that has been calculated based
    on the Guidelines from the original sentencing proceeding rather
    the ones in effect at the time of the § 404(b) proceeding itself.
    But, once it is so rooted in that way, it is free to account for
    all that it now knows.
    Yet, as much as the majority is willing to permit the
    district court to adopt a more presentist mindset in this important
    respect at step two of the inquiry, it is crucial to keep in mind
    how   temporally   constrained   the      majority's    approach   remains
    overall.   After all, it is critical to the majority's construction
    of § 404(b) that the second step of this two-step inquiry does not
    itself concern the threshold question -- posed only at the first
    step -- of whether the defendant's sentence should be reduced.          It
    instead concerns only the ancillary and follow-on question of how
    much the sentence should be reduced, which is a question that
    arises on the majority's account if and only if the decision at
    the first step to reduce the sentence at all has already been made
    to the defendant's benefit.
    Thus, the upshot of the majority's approach, taken as a
    whole, is this:    no post-sentencing developments other than the
    First Step Act's own mandate to give retroactive effect to the
    Fair Sentencing Act may inform the district court's decision as to
    whether to reduce the defendant's sentence.            Accordingly, under
    - 40 -
    the majority's approach, no weight may be given at all in making
    that critical threshold judgment to (1) post-sentencing statutory
    or Guidelines changes unrelated to the crack-powder disparity,
    (2) the overturning of the defendant's prior convictions that had
    been relied on to determine his criminal history category, or even
    (3) the defendant's admirable post-sentencing conduct.    And that
    is so not only when it comes to deciding what considerations may
    inform the setting of the GSR to be used at the § 404(b) proceeding
    but also when it comes to deciding whether any reduction at all is
    warranted in the defendant's original sentence given the GSR that
    applies at that proceeding to revisit that sentence.
    B.
    For the reasons that I will next explain, I do not share
    the majority's bifurcated understanding of how a district court
    may proceed -- temporally speaking -- under § 404(b).     No other
    circuit distinguishes between the "whether to reduce" and "how
    much to reduce" determinations with regard to the consideration
    that a district court may give under that provision of the First
    Step Act to developments that post-date the original sentencing
    proceeding (beyond, of course, the development expressly brought
    about by the First Step Act's requirement to apply the Fair
    Sentencing Act retroactively).5      And, even assuming that the
    5Other circuits have, however, adopted the slightly different
    two-step approach that I advance, in which the GSR calculation is
    - 41 -
    reduction decision is not better conceived to be a more holistic
    endeavor than the majority makes it out to be, I see no reason
    that we should become the first circuit to do so.
    I note that § 404(b) supplies no textual support that I
    can see for distinguishing between these two types of discretionary
    determinations   in   the   manner   that   the   majority   does.   That
    provision appears merely to make a unitary discretionary grant of
    authority to "impose a reduced sentence" without purporting to
    carve it up into discrete judgments subject to distinct temporal
    constraints.6
    constrained but both discretionary questions -- whether and how
    much to reduce the sentence -- can be informed by at least some
    intervening developments.    See, e.g., United States v. Foreman,
    
    958 F.3d 506
    , 513 (6th Cir. 2020) ("[A] district court is
    authorized to do two things with respect to a defendant's covered
    offense: (1) determine the statutory and Guidelines ranges 'as if
    sections 2 and 3 of the Fair Sentencing Act were in effect at the
    time the covered offense was committed,' and (2) exercise its
    discretion to impose a new sentence somewhere between the revised
    statutory minimum and the existing sentence. . . . [T]he First
    Step Act imposes no additional constraints on a district court's
    discretion once it determines the statutory and Guidelines ranges
    'as if' the Fair Sentencing Act had been in effect before 2010.");
    see also United States v. Moore, 
    975 F.3d 84
    , 89 (2d Cir. 2020)
    ("First, the court must determine whether the defendant is eligible
    for a reduction. Second, if the defendant is eligible, the court
    must determine whether, and to what extent, to exercise its
    discretion to reduce the sentence."); United States v. McDonald,
    
    944 F.3d 769
    , 771 (8th Cir. 2019) (similar).
    6  Concededly, that grant of authority in § 404(b) is
    conditional, but the chief condition -- set forth in the "as if"
    clause -- does not by terms purport to speak to whether the clock
    stops at the original sentencing proceeding or the § 404(b)
    proceeding as to either the question of whether to reduce the
    original sentence or the question of by how much to reduce it if
    - 42 -
    Moreover, the background against which § 404(b) was
    enacted and the purposes that underlie that provision combine in
    my view to demonstrate the problems with the way the majority
    resolves the ambiguities in § 404(b)'s text as to at least certain
    of the temporal questions presented here.           For, as I will explain,
    that background and those purposes indicate to me that this text
    should be construed to give the district court not only the
    discretion that the majority would afford it to account for
    intervening developments in deciding how much to reduce a sentence
    but also that same amount of discretion to account for those same
    intervening developments in making the threshold determination
    about whether to reduce the sentence at all.               Or, at least, the
    background and purposes suggest to me that the district court has
    such discretion once it has calculated the GSR based on the
    Guidelines   that   were   in   effect   at   the   time    of   the   original
    sentencing proceeding while duly accounting for the application of
    the Fair Sentencing Act mandated by § 404(b)'s "as if" clause.
    1.
    The majority implicitly accepts that the first temporal
    question that arises under § 404(b) is not the "whether to reduce"
    a reduction of any sort is in order. Thus, that conditioning "as
    if" clause draws no distinction between the "whether" and the "by
    how much" determinations. The clause on its face speaks instead
    only to the sentencing range that must be applied in the § 404(b)
    proceeding that must serve as the anchor for both of those
    determinations.
    - 43 -
    one that is its focus at the first step of its approach.                   Rather,
    the first temporal question is the logically prior one concerning
    how the district court must calculate the GSR to be used in the
    § 404(b) proceeding.         Indeed, under the majority's approach, the
    Fair Sentencing Act-adjusted GSR supplies the "initial benchmark"
    for the determinations that must be made under § 404(b) at each of
    the two steps it identifies.             See Gall, 
    552 U.S. at 49
    .7
    Thus, although the majority's two-step approach appears
    to me to collapse the temporal question of whether the old or the
    new   Guidelines      must   be   used    to   calculate   that   GSR    into   the
    necessarily follow-on temporal question of which considerations
    (old or new) may inform the "whether to reduce" determination, I
    think     it   is   important     separately    to   analyze   that     antecedent
    7Section 404(b) of the First Step Act does not by its terms
    require the district court to determine the newly applicable GSR
    before deciding whether to reduce the defendant's original
    sentence.   That provision incorporates provisions of the Fair
    Sentencing Act that change the statutory penalties setting the
    mandatory maximum and minimum sentence for certain crimes
    involving cocaine base. See Fair Sentencing Act of 2010, Pub. L.
    No. 111-220, 
    124 Stat. 2372
    . For defendants sentenced as career
    offenders, as Concepcion was, these statutory penalty changes
    affect the applicable GSR, too, because the offense level under
    the career offender Guideline is keyed to the statutory maximum
    for the offense of conviction.     See U.S.S.G. § 4B1.1(b).    The
    parties do not dispute that the district court must adjust the GSR
    at least to account for these changes.      And, doing so as the
    initial step in a sentencing proceeding is the standard practice
    across sentencing contexts, including in those modification
    proceedings permitting a district court to revisit a sentence in
    light of certain subsequent legal developments.     See Gall, 
    552 U.S. at 49
    ; Dillon v. United States, 
    560 U.S. 817
    , 827 (2010).
    - 44 -
    question first.      For, while I agree with the majority that the
    calculation of the GSR to be used at the § 404(b) proceeding must
    be based -- in the main -- on the old Guidelines, the reasons that
    lead me to that conclusion do not in my view support the majority's
    resolution    of   the   follow-on   temporal   question   regarding   the
    "whether to reduce" determination.
    a.
    Notably, the text of § 404(b) does not itself have much
    to say about which version of the Guidelines -- old or new -- is
    to be used to calculate the GSR that will control at a § 404(b)
    proceeding.    There is no express reference in this provision to
    the GSR that applies, let alone to how the GSR that is to be used
    at such a proceeding is to be calculated.
    The provision's "as if" clause does -- at least impliedly
    -- make clear that the GSR that applies in a § 404(b) proceeding
    cannot be the same one that was used in the original sentencing
    proceeding, at least insofar as the one that was used at that
    earlier time had been keyed to a statutory maximum that would not
    apply if the relevant Fair Sentencing Act provisions then had been
    in effect.     Otherwise, the taint of the disparate treatment of
    crack-cocaine offenses that the First Step Act aims to address
    would carry through to the § 404(b) proceeding itself.
    But, the "as if" clause does not make similarly clear
    whether, in calculating the GSR to be used at a proceeding under
    - 45 -
    that provision, the district court must use the Guidelines that
    were in effect at the time of the original sentencing proceeding
    or those Guidelines that are in effect at the time of that
    revisiting proceeding.   It simply does not address that question.
    That is not to say that the "as if" clause makes no
    temporal reference.    It plainly does.   But, it does so only by
    referring back to the time of the commission of the offense.   And,
    while that time frame is one that makes sense for purposes of
    determining the statutory penalties, see Dorsey v. United States,
    
    567 U.S. 260
    , 272-73 (2012), it is not one that speaks to the
    version of the Guidelines that Congress intended for the district
    court to use in calculating the GSR in § 404(b) proceedings.    At
    the time of the offense's commission, after all, there had been no
    sentencing proceeding -- original or otherwise.
    Nor can the "as if" clause be thought to offer an
    implicit resolution of the temporal question concerning which
    version of the Guidelines to use in calculating the GSR for the
    § 404(b) proceeding itself.    That clause would not be rendered
    wholly superfluous, for example, if § 404(b) were construed to
    require that the Guidelines used to calculate the GSR for such a
    proceeding were the ones that are in effect at the time of that
    proceeding (save for any ex post facto concerns), rather than the
    ones that were in effect at the time of the original sentencing
    proceeding.   Indeed, in that event, the "as if" clause still would
    - 46 -
    usefully perform a clarifying role, by making plain how far back
    in time the Fair Sentencing Act would apply retroactively.
    All that said, the text of § 404(b) is not a complete
    cipher   with   respect   to   the   temporal    question   at   hand.   The
    reference to a "reduced" sentence in § 404(b) does provide a
    possible clue as to what Congress intended on that score, as it
    necessarily takes the district court back to the earlier sentence
    that the defendant originally received and thereby accords with
    the notion that the district court in a § 404(b) proceeding should
    understand itself to be adjusting -- or determining whether to
    adjust -- a sentence that has already been imposed rather than to
    be imposing an entirely new one afresh.
    Accordingly, the provision's text does in this respect
    provide a hook for concluding that Congress intended the district
    court to use the version of the Guidelines to calculate the GSR to
    use at the § 404(b) proceeding that it uses in other contexts in
    which it has been charged with revisiting a previously imposed
    sentence for a possible reduction.            Nor do I think we strain the
    word "reduced" too much by reading it to provide this hook.
    It is a familiar interpretive precept that, in resolving
    a statutory ambiguity, we may look to the pre-existing legislative
    foundation on which a new measure builds for insight into what
    Congress meant by the words it enacted.          It thus makes sense to me
    to look to what came before § 404(b) in analogous contexts to
    - 47 -
    resolve the ambiguity that is at issue here, which concerns the
    version of the Guidelines to use at the § 404(b) proceeding.           See
    United States v. Martin, 
    974 F.3d 124
    , 139 (2d Cir. 2020) (noting
    that "[t]o the extent the First Step Act is silent," it "makes
    sense to look to . . . analogous resentencing proceeding[s]" given
    that "it is more likely that Congress was adopting, rather than
    departing from, established assumptions about how our legal or
    administrative system works" (quoting Nat. Res. Def. Council, Inc.
    v. U.S. Food & Drug Admin., 
    760 F.3d 151
    , 166 (2d Cir. 2016))).
    b.
    Such a review turns out to be most instructive.          It
    reveals that, unlike in original sentencing proceedings, district
    courts   in    revisiting   proceedings   do   not   generally   use   the
    Guidelines that are in effect at the time of those proceedings.
    To the contrary, it has been clear since at least the
    2003 enactment of 
    18 U.S.C. § 3742
    (g)(1) that on remand a district
    court is to apply the Guidelines that were in effect at the time
    of a defendant's original sentencing to calculate the GSR that
    will be used in determining the punishment in the resentencing.
    See PROTECT Act, Pub. L. No. 108-21, 
    117 Stat. 650
     (2003) (codified
    at 
    18 U.S.C. § 3742
    (g)) ("In determining the range referred to in
    subsection 3553(a)(4), the court shall apply the guidelines issued
    by the Sentencing Commission . . . that were in effect on the date
    of the previous sentencing of the defendant prior to the appeal,
    - 48 -
    together with any amendments thereto by any act of Congress that
    was in effect on such date . . . .").      And, in the seemingly even
    more analogous context of sentence modification proceedings under
    
    18 U.S.C. § 3582
    (c)(2), the relevant statutory text has been
    understood by no less seasoned an interpreter than the United
    States Sentencing Commission in a way that led it similarly to
    require district courts to use the Guidelines provisions applied
    at the original sentencing proceeding (as modified only by the
    particular retroactive amendments that were the basis for the
    § 3582(c)(2) motion) to calculate the GSR for the modification
    proceedings themselves.   See U.S.S.G. § 1B1.10(b)(1); see also 
    28 U.S.C. § 994
    (a)(2)(C)   (providing    that   the   Commission   shall
    promulgate policy statements "that in the view of the Commission
    would further the purposes set forth in [
    18 U.S.C. § 3553
    (a)(2)],
    including the appropriate use of . . . the sentence modification
    provisions set forth in" 
    18 U.S.C. § 3582
    (c)).
    Thus, against that backdrop, I see little reason to
    assume that Congress meant for a revisiting proceeding under
    § 404(b) to be temporally distinct in such a fundamental respect
    from other revisiting proceedings.      Indeed, in light of the well-
    known practice in other types of revisiting proceedings of not
    setting the GSR to be used in them on the basis of contemporary
    Guidelines, it is reasonable to expect that if Congress did intend
    to depart from that practice here it would have been at least as
    - 49 -
    clear in making that intention known as it was in pronouncing in
    the "as if" clause that the otherwise inapplicable Fair Sentencing
    Act would apply.    See Martin, 974 F.3d at 139-40.
    c.
    This understanding of § 404(b) is reinforced by the
    First Step Act's apparent purposes.              Following the enactment of
    the Fair Sentencing Act, some defendants sentenced under the former
    disparity-tainted      regime     were    able   to    have      their   sentences
    revisited   pursuant    to   
    18 U.S.C. § 3582
    (c)(2),        based   on   the
    retroactive amendments that the Sentencing Commission promulgated
    in response to the Fair Sentencing Act.               See Dorsey, 
    567 U.S. at 273
     (explaining that the Fair Sentencing Act "require[d] the
    Commission to change the Guidelines in the wake of the Act's new
    minimums").     But,    given     the    limitations        on   eligibility    for
    § 3582(c)(2)   relief,    significant         gaps    to    relief   remained    --
    individuals sentenced as career offenders, like Concepcion, as
    well as those serving statutory mandatory minimum sentences and
    those whose GSR otherwise would not change as a result of the
    Commission's responsive amendments, were ineligible to have their
    sentences revisited under § 3582(c)(2).                    See United States v.
    Wirsing, 
    943 F.3d 175
    , 179 (4th Cir. 2019) (explaining these gaps).
    A reading of § 404(b) under which the Guidelines from
    the original sentencing proceeding (as adjusted by the impact of
    the retroactive application of the Fair Sentencing Act) also serve
    - 50 -
    as the starting point for calculating the GSR for the revisiting
    proceeding enables § 404(b) to fill those gaps.            See 164 Cong.
    Rec. S7020, S7021 (daily ed. Nov. 15, 2018) (statement of Sen.
    Durbin) (describing bill with the text ultimately passed in § 404
    as "giv[ing] a chance to thousands of people who are still serving
    sentences for nonviolent offenses involving crack cocaine under
    the old 100-to-1 rul[e] to petition individually" for a sentence
    reduction).     But such a reading also ensures that § 404(b) fills
    them in a manner that, sensibly, does not entitle the class of
    defendants to whom this opportunity for relief has been extended
    to a form of review of their original sentences based on a GSR
    calculated under a new and more favorable set of Guidelines than
    prevailed at their original sentencing just because they happened
    to become eligible for post-Fair Sentencing Act review later than
    those who were eligible to secure it through the auspices of
    § 3582(c)(2).     See United States v. Brown, 
    974 F.3d 1137
    , 1144
    (10th Cir. 2020) ("Our review demonstrates that Congress, when
    passing § 404, authorized only a limited change in the sentences
    of   defendants   who   had   not   already   benefitted   from   the   Fair
    Sentencing Act. . . . It follows that the First Step Act also does
    not empower the sentencing court to rely on revised Guidelines
    instead of the Guidelines used at the original sentencing.");
    accord United States v. Moore, 
    975 F.3d 84
    , 91 (2d Cir. 2020).
    - 51 -
    d.
    Thus, I agree with the majority's resolution of the first
    temporal   question   that   § 404(b)   presents,   which   concerns   the
    proper means of calculating the GSR to be used at a proceeding
    held pursuant to that provision.        Like the majority, I agree that
    the Guidelines to be used in calculating the GSR for that type of
    proceeding -- at least absent subsequent clarifying or retroactive
    amendments to them -- are the ones that were used in setting the
    GSR used at the original sentencing and not those in effect at the
    time of the § 404(b) proceeding itself.8
    2.
    We come, then, to the distinct and follow-on temporal
    question that § 404(b) also requires us to resolve, which concerns
    8 I do not read any circuit to have expressly held that the
    district court must apply the current Guidelines to determine the
    GSR for a § 404(b) proceeding.         And, given the nature of
    Concepcion's arguments to us, we need not decide whether
    intervening Guidelines amendments that are merely clarifying, cf.
    U.S.S.G. § 1B1.10(a)(2) (providing that "if a court applies an
    earlier edition of the Guidelines Manual" due to ex post facto
    concerns, "the court shall consider subsequent amendments [so long
    as they] are clarifying rather than substantive changes"); United
    States v. Sarmiento-Palacios, 
    885 F.3d 1
    , 4-5 (1st Cir. 2018)
    (discussing   the   use   of  clarifying   amendments   in   remand
    proceedings), or that are themselves retroactive, see United
    States v. Bethany, 
    975 F.3d 642
    , 652-53 (7th Cir. 2020) (concluding
    that "although the district court could have exercised its
    discretion to apply" retroactive Guidelines amendments to save the
    defendant the "extra step of filing a motion under § 3582(c)(2),"
    "it was not required to do so"); but see, e.g., United States v.
    Caraballo, 
    552 F.3d 6
    , 11 (1st Cir. 2008) (noting that § 3582(c)(2)
    is unavailable to defendants sentenced as career offenders where
    the retroactive amendment sought to be considered is not a change
    - 52 -
    whether a district court conducting a proceeding pursuant to that
    provision is just as temporally constrained when it comes to the
    "whether to reduce" question as it is in setting the GSR.                But,
    deploying the same interpretive logic that I deployed above to
    answer this temporal question, I conclude that the majority is
    wrong to resolve the temporal question in the constraining manner
    that it does.    For, as I will explain, the background to, and the
    purposes of, § 404(b) require me to conclude, unlike the majority,
    that the provision's textual ambiguities are best construed to
    permit   a   district   court   in   deciding   whether    to   reduce    the
    defendant's    original   sentence    to   account   for   post-sentencing
    developments (whether factual or legal) no less than the majority
    to the career offender Guideline); United States v. Stewart, 
    964 F.3d 433
    , 437-38 & 437 n.6 (5th Cir. 2020) (noting that for some
    defendants, such as career offenders, ineligible for § 3582(c)(2)
    relief, the "prospect of relief under the [Fair Sentencing Act]
    would prove illusory . . . if courts were obligated to calculate
    sentencing ranges . . . without the benefit of" those retroactive
    amendments promulgated in response to the Fair Sentencing Act),
    should be accounted for in determining the applicable GSR in
    § 404(b) proceedings. Nor for that same reason need we address
    related questions concerning intervening factual developments, cf.
    United States v. Ticchiarelli, 
    171 F.3d 24
    , 35 (1st Cir. 1999)
    (providing that the scope of the appellate court's remand may
    determine the effect that may be given to such intervening factual
    developments); U.S.S.G. § 1B1.10(b)(1) (providing that, in
    § 3582(c)(2) proceedings, the "court shall substitute only the
    amendments listed in subsection (d) for the corresponding
    guideline provisions that were applied when the defendant was
    sentenced and shall leave all other guideline application
    decisions unaffected" (emphasis added)), or intervening case law,
    see United States v. Chambers, 
    956 F.3d 667
    , 672-74 (4th Cir.
    2020), that might affect the GSR even under the old Guidelines.
    - 53 -
    agrees a district court may account for them in deciding by how
    much to reduce that sentence once it decides that some reduction
    is required.
    a.
    The only possible source of the temporal limitation that
    the majority would impose on the "whether to reduce" determination
    in the text of § 404(b) itself would appear to be found in that
    provision's "as if" clause.       But, as we have seen, that clause
    merely mandates that the statutory sentencing range -- and, by
    extension, the GSR -- that must be used in the § 404(b) proceeding
    is the one that obtained at the original sentencing proceeding as
    adjusted in accord with the mandated retroactive application of
    the Fair Sentencing Act.     Thus, that clause does not, by terms,
    purport to speak to this precise temporal issue at all.9
    Nor does § 404(b)'s "as if" clause impliedly speak to
    that issue in light of the way it interacts with the canon against
    superfluity.    See In re Montreal, Me. & Atl. Ry., Ltd., 
    799 F.3d 1
    , 9 (1st Cir. 2015) ("[C]ourts should construe statutes to avoid
    rendering    superfluous   any   words    or   phrases   therein.").   A
    9 Indeed, the fact that the only time frame referenced in the
    "as if" clause is the time of the commission of the offense
    indicates that Congress did not intend for the "as if" clause to
    dictate that a district court imagine itself to be inhabiting an
    earlier point in time in all respects. For, Congress could not
    have intended to direct a district court in a § 404(b) proceeding
    to imagine what sentence it would make sense to impose at a time
    when even the original sentencing proceeding had not yet occurred.
    - 54 -
    construction of § 404(b) that would confer on district courts the
    discretion   to    consider      intervening      developments         in   deciding
    whether to reduce a sentence would not render the "as if" clause
    meaningless, even though it would permit a district court to give
    weight to a favorable intervening change in the Guidelines.                     Such
    a construction still treats that clause as usefully performing the
    role of identifying the sentencing range to be used in the § 404(b)
    proceeding by specifying that it is the range that would apply if
    the Fair Sentencing Act had been in effect at the time of the
    commission of the underlying offense.
    The   majority      does    suggest   that    a     separate    textual
    limitation on discretion -- not to be found within § 404 itself --
    compels the resolution of the temporal issue that it embraces.
    The   majority        locates      that     limitation          in     
    18 U.S.C. § 3582
    (c)(1)(B)'s grant of authority to "modify an imposed term of
    imprisonment to the extent . . . expressly permitted by statute."
    
    Id.
     (emphasis added).
    To the majority, this "expressly permitted" language
    functions    as   a   global     clear-statement         rule    for    sentencing
    modification measures generally.            Thus, the majority concludes,
    this language requires us to read the express grant of authority
    in § 404(b) as narrowly as possible when it comes to the "whether
    to reduce" determination.
    - 55 -
    But,    such    a   reading      of     the   "expressly     permitted"
    language misconstrues the operation of § 3582(c)(1)(B), which is
    merely a finality exception that does not itself impose substantive
    limits.   Cf. United States v. Triestman, 
    178 F.3d 624
    , 629 (2d
    Cir. 1999) (Sotomayor, J.) (reading § 3582(c)(1)(B) not to impose
    its own limitations but merely to "note[] the authority to modify
    a sentence if modification is permitted by statute" (emphases
    omitted) (quoting S. Rep. No. 98-225 (1984), reprinted in 1984
    U.S.C.C.A.N.     3182,    3304)).     Thus,        insofar   as   the   revisiting
    proceeding at issue here is properly deemed a "modification"
    proceeding, it is enough to satisfy that textual requirement in
    § 3582(C)(1)(B) in my view that § 404(b) "expressly permit[s]"
    modification.     And, that being so, we must look to § 404(b) itself
    -- and not elsewhere -- for any limits on the extent of the
    modification that is allowed, precisely because that provision
    does expressly permit a modification to be made. See United States
    v. Kelley, 
    962 F.3d 470
    , 477 (9th Cir. 2020) ("[T]he First Step
    Act expressly permits a specific type of sentence reduction, and
    we   interpret    and    implement   such     an    independent    congressional
    statute on its own terms.").
    b.
    What, then, are the limits that § 404(b) imposes when it
    comes to the precise temporal question before us at this juncture
    of the analysis, which concerns a district court's discretion as
    - 56 -
    to whether to reduce a sentence once the Fair Sentencing Act has
    been given its requisite retroactive effect?        Once again, because
    the text of § 404(b) provides no clear answer, I find it most
    helpful to consider the backdrop against which Congress enacted
    the provision.      See Martin, 974 F.3d at 139-40.
    I do not mean to suggest that we may simply pick and
    choose from the rules that govern previously established federal
    sentencing frameworks in construing § 404(b) in this connection.
    We have no warrant to select those aspects of them that we like
    and to discard those that we do not in determining the rules that
    are to be operative under § 404(b).
    I do mean to suggest, however, that, insofar as the face
    of § 404(b) is not clear one way or the other as to how it is to
    be construed on a crucial interpretive point, then we should apply
    the familiar tools of statutory interpretation to resolve that
    ambiguity.    And, as those familiar tools include considerations of
    the background understandings against which Congress legislated,
    there   is   good   reason   to   give   interpretive   weight   to   those
    understandings in resolving the ambiguity at hand.
    Indeed, the evident remedial purposes of the First Step
    Act, see United States v. White, 
    984 F.3d 76
    , 89-90 (D.C. Cir.
    2020) (detailing the remedial purpose of the First Step Act and
    arguing that it should be understood in light of that purpose),
    accord with following such an interpretive course.         They suggest,
    - 57 -
    if anything, a reason to presume that Congress would have wanted
    to confer no less discretion in this context than it has conferred
    in seemingly similar ones, especially given the discretionary
    manner in which the federal sentencing framework as a whole
    operates.      Cf.    Pepper,      562    U.S.   at    488-91     (discussing     the
    "longstanding       principle"      granting      sentencing       courts    "broad
    discretion to consider various kinds of information" (quoting
    United States v. Watts, 
    519 U.S. 148
    , 151 (1997))).
    For that reason, I find it instructive in construing
    Congress's intent that it was well understood prior to § 404(b)'s
    passage that, on remand of a sentence, the district court, once it
    has identified the applicable GSR for that revisiting proceeding
    based on the Guidelines that were in place at the time of the
    original sentencing, is still free to consider post-sentencing
    developments in selecting the new sentence in light of that
    anchoring GSR.       See Pepper v. United States, 
    562 U.S. 476
    , 490
    (2011) ("In light of the federal sentencing framework . . . , we
    think it clear that when a defendant's sentence has been set aside
    on appeal and his case remanded for resentencing, a district court
    may consider evidence of a defendant's rehabilitation since his
    prior sentencing . . . .").              And I find it instructive as well
    that   the   same    was   understood      to    be   true   in   the   context    of
    modification proceedings under 
    18 U.S.C. § 3582
    (c)(2), once the
    GSR    has   been   set    using   the     old   Guidelines.        See     U.S.S.G.
    - 58 -
    § 1B1.10(b); id. § 1B1.10 cmt. n.1(B).                     As the Commission has
    recognized, moreover, that is true not only with respect to the
    "by how much" question but also with respect to the threshold
    "whether" question.        See id. § 1B1.10 cmt. n.1(B)(iii) ("The court
    may    consider    post-sentencing         conduct        of    the    defendant     that
    occurred    after       imposition    of    the     term        of    imprisonment      in
    determining:       (I) whether a reduction in the defendant's term of
    imprisonment       is    warranted;        and     (II) the          extent     of   such
    reduction . . . ."); see also Chavez-Meza v. United States, 
    138 S. Ct. 1959
    , 1967 (2018) (assuming that post-sentencing developments
    were properly before the district court).
    I thus see little reason to conclude that Congress must
    have silently intended not to permit a district court to exercise
    a similar amount of discretion pursuant to § 404(b) to consider
    things as they are at present.             Rather, I would read that cryptic
    text   to   have    been   intended    to        permit    a    district       court,   in
    identifying any new sentence, to account for new developments in
    the same manner just described, given that they may be accounted
    for on a remand or in a run-of-the-mill modification proceeding.
    Of course, it would not make sense to conclude that
    Congress intended in enacting § 404(b) to give its beneficiaries
    extra-special       treatment    relative          to     their       fellow    intended
    beneficiaries of the Fair Sentencing Act.                      That is in part why I
    agree with the majority that a district court in a § 404(b)
    - 59 -
    proceeding must derive the GSR from the Guidelines in effect at
    the original sentencing.
    But, as I have explained, the purpose and history of the
    First Step Act demonstrate that Congress wanted § 404(b)-eligible
    defendants to have an opportunity for relief at least roughly
    equivalent      to     that   afforded     to      those      § 3582(c)(2)-eligible
    defendants who already had an opportunity to have their sentences
    revisited in light of the changes effected by the Fair Sentencing
    Act.     It thus, in my view, counts rather strongly against the
    majority's approach to the temporal constraints that district
    courts must labor under in conducting § 404(b) proceedings that
    those defendants who seek reductions under that provision would be
    worse off under it in this respect than those who seek them under
    
    18 U.S.C. § 3582
    (c)(2).             After all, it is clear that district
    courts    revisiting          sentences       in      § 3582(c)(2)       modification
    proceedings      are    permitted     to   give       favorable        post-sentencing
    developments     weight       in   deciding     not    just      the   extent   of   the
    reduction of a sentence but also whether to reduce a sentence at
    all,   even     if   those     developments        may     not    be   considered    in
    calculating the applicable GSR for the modification proceedings
    themselves.      See U.S.S.G. § 1B1.10 cmt. n.1(B)(iii).
    I do recognize that it is merely Sentencing Commission
    commentary that most clearly confirms as much in the § 3582(c)(2)
    modification context. See U.S.S.G. § 1B1.10(a)(1).                          But, that
    - 60 -
    commentary does reflect the Commission's evident understanding of
    the text of 
    18 U.S.C. § 3582
    (c)(2), which authorizes a district
    court to "reduce" a prior sentence based on a retroactive legal
    change.
    Thus, that commentary suggests to me that the Commission
    understood that statutory text to be susceptible of a construction
    that would read it simultaneously to instruct district courts to
    calculate the GSR to be used in the modification proceeding based
    on the Guidelines in effect at the time of the original sentencing
    (as adjusted by retroactive application of the Fair Sentencing
    Act)    and    to   take   account   of   post-sentencing     developments    in
    deciding whether to reduce that sentence in light of that GSR.
    See U.S.S.G. § 1B1.10(b)(1); U.S.S.G. § 1B1.10 cmt. n.(1)(B)(iii).
    That    is    significant,    in   my    view,   because   § 404(b)   similarly
    authorizes district courts to "impose a reduced sentence" based on
    the retroactive legal change brought about by § 404(b).                Why not,
    then,    conclude     that   Congress     similarly   contemplated     in   this
    context that a district court could operate in this same variable
    temporal manner, such that it could rely on present-day knowledge
    in deciding whether a reduction is warranted under § 404(b), even
    though it must draw on the old Guidelines to calculate the GSR
    that anchors that decision?          See Martin, 974 F.3d at 139 ("[I]t is
    helpful to look at the parallels between section 3582(c)(2) and
    - 61 -
    the First Step Act to resolve background questions regarding the
    mechanics of the First Step Act.").10
    Of course, if our aim is to construe § 404(b)'s text to
    accord with the way § 3582(c)(2) had been understood in the
    relevant respect, then I acknowledge that it is important to
    account for the fact that § 3582(c)(2) expressly refers to the 
    18 U.S.C. § 3553
    (a) factors while § 404(b) does not.               But, I am not
    persuaded that this difference between these two texts shows that
    Congress intended to give district courts less discretion --
    temporally -- to remedy a past injustice based on a retroactive
    change in the law under the First Step Act than they have to remedy
    such an injustice in an ordinary modification proceeding.
    Implicit in the idea of deciding whether to impose a
    reduced sentence is some consideration of the § 3553(a) factors --
    and   that   is   no   less   true   under    § 404(b)   than   it   is   under
    § 3582(c)(2).      The majority itself acknowledges as much in its
    recognition that the "original calibration of the section 3553(a)
    factors" still properly informs the district court's decision
    whether to reduce a sentence.        Maj. Op. at 21.     Thus, the inclusion
    It is important to emphasize that each ambiguity in § 404(b)
    10
    must be taken on its own terms. There is a difference between
    construing an ambiguity using background context and ordinary
    interpretive tools and importing an arbitrary limitation into
    § 404.   For example, I cannot see any reason to import the
    limitation on the extent of a sentence reduction in § 3582(c)(2)
    proceedings, see U.S.S.G. § 1B1.10(b)(2), into the § 404(b)
    context.
    - 62 -
    of a reference to § 3553(a) in § 3582(c)(2) but not in § 404(b)
    cannot   in    and     of   itself    be    understood      to   suggest    that   no
    consideration of the § 3553(a) factors at all may be given in a
    § 404(b) proceeding.
    That,    then,      leaves    only    the    possibility     that    the
    inclusion of the reference to § 3553(a) in § 3582(c)(2) but not in
    § 404(b)   supplies         the   basis     for    concluding    that   intervening
    considerations        may    be   given     weight    in   the   former    type    of
    proceedings but not the latter.              But, that, too, does not follow.
    Section 3582(c)(2)'s mandate to consider the § 3553(a)
    factors does not itself purport to specify whether district courts
    are to use the "new" or the "old" § 3553(a) factors in doing so.
    Thus, it cannot be that the inclusion of the bare reference to
    § 3553(a) in § 3582(c)(2) and its absence from § 404(b) compels
    drawing such a temporal distinction those two types of proceedings
    when it comes to the § 3553(a) analysis that is necessarily
    relevant to each.
    Put     otherwise,     even     after    comparing    the    text     of
    § 3582(c)(2) and § 404(b), we necessarily come back to the same
    basic temporal question that § 404(b) does not by its terms purport
    to resolve: Must the § 3553(a) analysis be informed only by things
    as they were, or can it also be informed by things as they are?
    And, as I have explained, precisely because the text of the First
    Step Act does not clearly answer that question one way or the
    - 63 -
    other, I see no reason to construe it in a way that would render
    it out of step with the way revisiting proceedings otherwise
    proceed.
    Indeed,   the   majority      itself   finds   a    new   § 3553(a)
    analysis permissible to some extent -- in deciding the extent of
    a reduction if one is in order -- and yet it provides no textual
    explanation for drawing this line where it does.           Nor has any other
    court, to my knowledge, found such a textual basis.
    A construction that would extend that same temporal
    discretion to the "whether to reduce" determination also makes
    good   practical     sense.      Like     run-of-the-mill        modification
    proceedings, § 404(b) proceedings are in many cases occurring well
    after a defendant's original sentencing proceeding.             That makes it
    a   potentially   difficult    and    senseless    task   to   determine    the
    "original calibration" of the § 3553(a) factors. See United States
    v. Rose, 
    379 F. Supp. 3d 223
    , 235 (S.D.N.Y. 2019) ("[G]iven the
    length of the sentences at issue in crack-cocaine cases, there is
    a high degree of likelihood that many of the judges considering
    the First Step Act motion will not be the original sentencing
    judge."); see also, e.g., United States v. King, 
    423 F. Supp. 3d 481
    , 489 (M.D. Tenn. 2019) (finding that because the defendant
    seeking a reduction pursuant to § 404(b) was "sentenced more than
    a decade and a half ago by a judge who has since retired" and
    because    the    sentencing    transcript        demonstrated       that   the
    - 64 -
    defendant's "sentence was very much tied to the statutory mandatory
    minimum," thus "beg[ging] the question of whether the sentence
    would have been less if the statutory floor were only ten instead
    of twenty years[,] . . . it falls on this Court to make that
    determination and the only effective way to do so is by considering
    the [§] 3553(a) factors," the use of which "also necessitates that
    the Court consider [post-sentencing] rehabilitation").
    The reason to be wary of concluding that Congress must
    have intended to impose such a bar as the majority embraces would
    seem to be especially strong, moreover, when the Supreme Court has
    recognized that such intervening facts as a defendant's admirable
    post-sentencing conduct can be "highly relevant to several of the
    § 3553(a) factors."       See Pepper, 
    562 U.S. at 491
    .     And, as I have
    noted, the Guidelines commentary expressly permits consideration
    of post-sentencing conduct in § 3582(c)(2) sentence modification
    proceedings.   See U.S.S.G. § 1B1.10 cmt. n.1(B)(iii).
    c.
    For all of these reasons, then, it is a mistake in my
    view to read § 404's silence with respect to the temporal questions
    that arise once the GSR is in place (based as it must be on the
    old Guidelines) in the constraining manner that the majority does
    with respect to the "whether to reduce" determination.              Such a
    reading   requires   us    to   conclude   that,   with   respect   to   the
    consideration of intervening developments in deciding whether a
    - 65 -
    sentence reduction is in order, Congress meant for people who were
    relying on the Commission's response to a disparity to be better
    off   than   people   relying   on    Congress's   own   response   to   that
    disparity.
    3.
    There remains, then, just one loose interpretive end
    with regard to the framework that § 404(b) generally establishes.
    It concerns the distinction that some courts have drawn between
    intervening factual developments (such as the defendant's post-
    sentencing conduct or the vacatur of his prior convictions) and
    intervening legal ones (such as the advent of Guidelines amendments
    that would be favorable to the defendant, even if they have not
    been made retroactive).     See, e.g., United States v. Robinson, 
    980 F.3d 454
    , 463 (5th Cir. 2020) (explaining that the Fifth Circuit
    has precluded district courts from "consider[ing] other post-
    sentencing changes in the law" aside from those mandated by the
    Fair Sentencing Act, but noting that the Fifth Circuit has "not
    h[eld] that [district] court[s] cannot consider post-sentencing
    conduct" (quoting United States v. Jackson, 
    945 F.3d 315
    , 321, 322
    n.7 (5th Cir. 2019))); Kelley, 962 F.3d at 474 & n.4, 475 (holding
    that the First Step Act "does not authorize the district court to
    consider other legal changes that may have occurred after the
    defendant committed the offense" but not addressing whether it was
    - 66 -
    permissible that the district court considered that the defendant
    "had been a model inmate during her incarceration").
    The courts that have concluded that § 404(b) draws this
    line appear to have relied on the expressio unius canon to tease
    out the First Step Act's meaning, treating the "as if" clause's
    singling out of that one legal change as a sign that Congress
    impliedly intended to preclude the consideration of any other legal
    change.   See United States v. Hegwood, 
    934 F.3d 414
    , 418-19 (5th
    Cir. 2019); Kelley, 962 F.3d at 475.11   The government argues that
    we should do the same.   But, I do not agree.
    Although the "as if" clause refers only to the Fair
    Sentencing Act, it does not do so, as I have explained, in a way
    that necessarily gives rise to a preclusive inference with respect
    to the propriety of giving mere consideration in selecting a
    sentence to intervening legal developments other than the one
    brought about by the clause itself.        Nor am I alone in so
    concluding.   See United States v. Hudson, 
    967 F.3d 605
    , 612 (7th
    Cir. 2020) ("The First Step Act does not prevent the court from
    considering [the change to the defendant's career offender status]
    when deciding whether the sentence imposed is 'sufficient, but not
    11 Because these courts were considering requests for a new
    Guidelines calculation accounting for legal changes, which I agree
    is impermissible, it is not clear that they would preclude
    consideration of legal changes against a GSR that does not itself
    reflect those changes.
    - 67 -
    greater         than      necessary,'                under        
    18 U.S.C. § 3553
    (a). . . . '[T]oday's Guidelines may reflect updated views
    about   the    seriousness     of    a    defendant's    offense       or   criminal
    history.'" (quoting United States v. Shaw, 
    957 F.3d 734
    , 742 (7th
    Cir. 2020))); United States v. Harris, 
    960 F.3d 1103
    , 1106 (8th
    Cir. 2020) ("[T]he § 3553(a) factors in First Step Act sentencing
    may include consideration of the defendant's advisory range under
    the current guidelines.").
    I thus find myself in a by-now-familiar position:                       I
    face the question under § 404(b) about how much discretion a
    district court has to account for present realities that the text
    of that provision does not answer with any clarity.                    And so, for
    me, the right way through is to follow the now-familiar approach
    of resolving that ambiguity in a manner that most aligns § 404(b)
    with other revisiting proceedings.
    Following that course, I find it significant that this
    Court has repeatedly recognized that legal changes, even when not
    used to set the GSR that serves as the benchmark, can inform the
    district court's exercise of its discretion to select a reasonable
    sentence in light of that benchmark.              See, e.g., United States v.
    Frates,   
    896 F.3d 93
    ,    102   (1st     Cir.    2018)     (recognizing    the
    distinction between recalculating the GSR on remand to account for
    intervening nonretroactive amendments, which would "circumvent the
    Sentencing      Commission's    non-retroactivity            determination,"     and
    - 68 -
    considering     intervening        legal    changes     that     reflect    "the
    Commission's       revised    policy       position"    in     exercising    the
    "discretion to select an appropriate sentence"); United States v.
    Godin, 
    522 F.3d 133
    , 136 (1st Cir. 2008) (per curiam) (noting that
    the Sentencing Commission's "current thinking" about, for example,
    who   may     be     deemed    a      career    offender,       may    properly
    "influence . . . the judge's ultimate discretionary choice of
    sentence"); United States v. Rodriguez, 
    630 F.3d 39
    , 42 (1st Cir.
    2010) (finding that courts that must "start with old Guidelines"
    can still "consult new ones in choosing suitable sentences," as
    "Guidelines    revisions      [can]    help    [courts]      select   reasonable
    sentences that (among other things) capture the seriousness of the
    crimes and impose the right level of deterrence").                And, I note,
    we have come to that conclusion despite the express directions
    that Congress has given about which legal changes could be relied
    upon to calculate the applicable GSR.                  See, e.g., 
    18 U.S.C. § 3742
    (g)(1); see also U.S.S.G. § 1B1.11(b)(1).
    To be sure, this body of precedent concerns the proper
    approach for a district court to take on the remand of a sentence
    from a direct appeal and that is a type of revisiting proceeding
    in which the prior sentence is -- strictly speaking -- no longer
    in place.      Here, by contrast, there is a presumptively valid
    sentence from which a reduction is being sought.               For that reason,
    I suppose, it is possible to understand sentence selection in this
    - 69 -
    context to entail not simply a choice of length but also a distinct
    initial question as to whether the original sentence remains
    appropriate -- in other words, to entail both a "whether to reduce"
    inquiry and a "by how much to reduce," insofar as a reduction is
    warranted at all, inquiry.
    But, even if one accepts that it is not artificial to
    divvy up the task of sentence selection under § 404(b) in that
    two-step manner, that very same type of task is required in a
    § 3582(c)(2) modification proceeding.           There, too, a reduction
    from a sentence that is presently in place is being sought based
    on an expressly identified retroactive legal change.          I know of no
    precedent, however, that holds that a subsequent, nonretroactive
    Guidelines change favorable to the defendant may not even be
    considered -- once the GSR has been calculated for use at the
    modification proceeding independent of such a change -- in deciding
    whether   to   modify   the   sentence   in   such   proceedings.   And   I
    certainly know of none suggesting that while such a legal change
    may not be considered for that purpose it may be considered in
    determining the extent of the modification.12
    12 I am aware that in Dillon, 
    560 U.S. at 831
    , the Supreme
    Court rejected the defendant's contention that the district court
    should have considered intervening legal changes.        The Court
    concluded that because "the aspects of his sentence that Dillon
    seeks to correct were not affected by the Commission's amendment
    to § 2D1.1, they are outside the scope of the proceeding authorized
    by § 3582(c)(2), and the District Court properly declined to
    address them."     
    560 U.S. at 831
    .      But, Dillon requested a
    - 70 -
    Thus, here, too, in the face of the relevant ambiguity
    occasioned by § 404(b)'s brief text, I think it sensible to proceed
    on the understanding that Congress intended for the conduct of
    revisiting proceedings under that provision to be similar to the
    conduct of them more generally.              And, in this limited respect, I
    note     that    I   am    actually   in    interpretive   agreement   with     the
    majority, which similarly sees nothing in § 404(b) that would
    permit factual and legal considerations to be treated differently
    as   a   temporal         matter.     See   also   Jackson,   945   F.3d   at   321
    recalculation of the sentence to correct a Booker error and adjust
    the criminal-history category. See id.; see also United States v.
    Jordan, 
    162 F.3d 1
    , 3-5 (1st Cir. 1998) (concluding that
    § 3582(c)(2) did not permit defendant to obtain benefit of U.S.S.G.
    § 5K2.0 departure not applied at original sentencing). As I have
    explained, this Court has recognized the difference between
    accounting for intervening legal and factual developments to
    recalculate the Guidelines range and considering them "as a
    discretionary factor." Frates, 896 F.3d at 102-03.
    I am also aware that a district court under § 3582(c)(2)
    generally cannot reduce the sentence below the GSR that obtains
    after having been adjusted to account for retroactive amendments.
    See Dillon, 
    560 U.S. at 822
     ("Except in limited circumstances,
    . . . [U.S.S.G.] § 1B1.10(b)(2)(A) forecloses a court acting under
    § 3582(c)(2) from reducing a sentence 'to a term that is less than
    the minimum of the amended guideline range.'"). But, Guidelines
    changes that are not retroactive could in that context still impact
    where to set the sentence in relation to that range (especially if
    the original sentence was set at its higher end), and, in any
    event, nothing in § 404 suggests that the limitation on the extent
    of a reduction that is allowable in § 3582(c)(2) modification
    proceedings applies to § 404(b) proceedings.          See U.S.S.G.
    § 1B1.10(a)(1)    (referring   only   to   § 3582(c)(2)    sentence
    reductions).    Compare First Step Act § 404, with 
    18 U.S.C. § 3582
    (c)(2) (providing that such a reduction must be "consistent
    with applicable policy statements by the Sentencing Commission").
    - 71 -
    (recognizing that disparate treatment of post-sentencing legal and
    factual developments "make[s] little sense").
    C.
    To sum up, then, I do not agree with the majority's
    bifurcated treatment of the temporal issue that § 404(b) requires
    us to resolve. In my view, when confronted with an eligible
    defendant's § 404(b) motion, the district court must proceed as
    follows.
    The district court first must determine the statutory
    sentencing range and the GSR to be used in assessing whether to
    reduce the defendant's sentence as requested.                     In making those
    determinations, moreover, the district court must rely on the
    relevant provisions of the Fair Sentencing Act as if they had been
    in   effect    when    the    offense    was       committed,    while      using   the
    Guidelines     that    were   operative       at    the   time   of    the   original
    sentencing proceeding (save for the potential caveats I have noted)
    and not those presently in effect.
    But,    although   these    conclusions        align     me    with   the
    majority's approach under § 404(b) to this point, the logic that
    leads me to them requires me to break with its view of how a
    district      court    conducting   a    § 404(b)         proceeding     should     act
    thereafter.      For, in my view, given the purposes and background
    against which Congress legislated in passing the First Step Act,
    the district court, having set the range in the manner just
    - 72 -
    described, is as free to consider intervening developments (both
    factual and legal) in making the gating decision under § 404(b) as
    to whether to impose a reduced sentence (based on a GSR in whose
    determination such developments played no role) as it is under the
    majority's approach to consider those developments in making the
    follow-on assessment of how much to reduce the original sentence.
    III.
    With this framework in mind, I am now finally ready to
    take up the question of whether Concepcion is right to contend
    that, in this particular case, the District Court abused its
    discretion in declining to reduce his sentence.    I conclude that
    he is -- in part.
    I am not persuaded by Concepcion's contention that the
    District Court abused its discretion by refusing to use the
    Guidelines in place at the time of the § 404(b) proceeding to
    calculate the newly applicable GSR.    For the reasons that I have
    already set forth at some length, I see no basis for construing
    § 404(b) to be such an outlier relative to other provisions
    structuring revisiting proceedings.
    But, I also am not persuaded by Concepcion's contention,
    which I have not yet addressed, that the District Court abused its
    discretion when it failed to conduct a rebalancing of the § 3553(a)
    factors with respect to its assessment of whether subsequent
    factual developments -- such as those that Concepcion highlighted
    - 73 -
    pertaining to his admirable post-sentencing conduct.           For, even if
    I were to assume, as Concepcion contends, that such a rebalancing
    is obligatory (as opposed to merely permissible) under § 404(b),
    I still see no ground for finding error on this score in his case.
    We have previously recognized that "simply because the
    district court didn't expressly mention" intervening developments
    in its ruling on a sentence reduction motion "doesn't mean it
    didn't consider" them.      United States v. Rodríguez-Rosado, 
    909 F.3d 472
    , 480 (1st Cir. 2018).       And, it is a familiar proposition
    that   a   sentencing   court   is   not   required   to   "verbalize   its
    evaluation of each and every [§] 3553(a) factor," United States v.
    Reyes-Rivera, 
    812 F.3d 79
    , 89 (1st Cir. 2016), or to "afford each
    of the § 3553(a) factors equal prominence," United States v. Sosa-
    González, 
    900 F.3d 1
    , 5 (1st Cir. 2018).          Instead, the district
    court only must "set forth enough to satisfy the appellate court
    that [it] has considered the parties' arguments and has a reasoned
    basis for exercising [its] legal decisionmaking authority."             Rita
    v. United States, 
    551 U.S. 338
    , 356 (2007).
    The fact that a district court does not consider a
    sentence on a blank slate under § 404(b) must be kept in mind as
    well in evaluating the district court's explanation of its decision
    in a proceeding held pursuant to that provision.           Cf. Chavez-Meza,
    
    138 S. Ct. at 1967
     (concluding that, when considering an appeal
    from a § 3582(c)(2) sentence modification, reviewing courts "need
    - 74 -
    not turn a blind eye" to the reasons the judge gave at the initial
    sentencing).   For, because intervening factual developments might
    impact some elements of the § 3553(a) analysis while leaving others
    unaffected, a district court's failure to highlight intervening
    changes may only suggest "that the district court may have been
    unimpressed or unpersuaded by" them.     Rodríguez-Rosado, 909 F.3d
    at 480.
    Thus, even if Concepcion is right that a present-day
    rebalancing of the § 3553(a) factors is required under § 404(b),
    I conclude that the explanation that the District Court provided
    here was sufficient to assure us that it had a "reasoned basis for
    exercising [its] legal decisionmaking authority," Chavez-Meza, 
    138 S. Ct. at 1966
     (quoting Rita, 
    551 U.S. at 356
    ), with respect to
    its decision not to reduce the sentence based on the intervening
    factual developments that Concepcion identified, see 
    id.
     (assuming
    that the "reasoned basis" standard applied in the § 3582(c)(2)
    context and finding it satisfied where the judge -- who had also
    imposed the defendant's original sentence -- did not address the
    parties' arguments about the defendant's post-sentencing conduct
    while in prison).   Accordingly, there was no abuse of discretion
    here in this regard.
    I do note, though, that my reason for so concluding is
    not the same as the majority's.        Under its view, intervening
    factual considerations may not be considered in making the "whether
    - 75 -
    to   reduce"     determination.       Under   mine,    by    contrast,     those
    considerations may be considered.         In fact, it is only because --
    as far as I can tell -- Concepcion's claim of error on this score
    has no merit in his particular case that I reject it.
    That brings us, then, to Concepcion's final contention,
    which is that the District Court abused its discretion in declining
    to reduce his sentence because it failed to recognize that it could
    consider     intervening     legal     changes   --        specifically,     the
    Commission's intervening changes to the career offender Guideline
    --   in    his   § 404(b)   proceeding.       Here,    I    am   persuaded    by
    Concepcion's challenge.
    The District Court appears to have declined to consider
    that intervening change because it was of the view that it was
    barred -- as a matter of law -- from considering such intervening
    legal developments in exercising its discretion in any respect
    under § 404(b) of the First Step Act.                 See United States v.
    Concepcion, No. 07-10197, 
    2019 WL 4804780
    , at *3-5 (D. Mass. Oct.
    1, 2019).13      This aspect of the District Court's analysis, of
    13 In assessing whether the First Step Act permits
    "consider[ation] [of] any intervening changes in the law other
    than those made by the Fair Sentencing Act," the District Court
    relied on the Fifth Circuit's analysis in Hegwood and concluded
    that, because "Amendment 798 derives from an entirely different
    source" than the Fair Sentencing Act, it is "not clear that
    Amendment 798's changes are a permissible ground for resentencing
    under the First Step Act." Concepcion, 
    2019 WL 4808780
    , at *3-4
    (citing Hegwood, 934 F.3d at 418). The District Court's analysis
    of its possible power to take account of this Guidelines change is
    - 76 -
    course, causes no concern for the majority.          In its view, the
    District Court correctly ascertained this legal bar to its exercise
    of discretion, given that such considerations could only come into
    play at what the majority describes as the second step of the
    inquiry -- which concerns only the extent of the reduction and not
    whether one is needed at all, and which the majority views the
    District Court as never having reached.
    But, for the reasons I have explained, I read § 404(b)
    to   permit   a   district   court   to   consider    post-sentencing
    developments once it has determined the proper GSR, based on the
    Fair Sentencing Act's retroactive application.       I thus understand
    the District Court here to have misapprehended the scope of its
    discretion -- as a matter of law -- to consider the fact that
    Concepcion may no longer qualify as a career offender under current
    Guidelines in making its gating determination about whether to
    reduce the sentence at all.14
    best read to reflect its legal view that the First Step Act barred
    it from considering that new legal development and then its
    separate assessment -- outside of the Act -- of whether 
    18 U.S.C. § 3582
    (c)(2), see id. at *4, or the Godin/Ahrendt doctrine, see
    id. at *5 & n.1, nonetheless permitted it to consider the
    development.
    14  Although the majority notes that the District Court
    "consider[ed] the amended career offender guideline, noted that
    the Sentencing Commission had declined to make it retroactive, and
    decided not to pantomime it as a matter of discretion," Maj. Op.
    at 28-29, the District Court's consideration of Amendment 798 was,
    crucially, undertaken only outside the rubric of the First Step
    Act.   As discussed supra note 10, the District Court's opinion
    - 77 -
    Such   a   misapprehension   about   the   extent   of   the
    discretion that a statute confers is -- as I noted at the outset
    of this journey -- a classic abuse of discretion.           See United
    States v. Snyder, 
    136 F.3d 65
    , 67 (1st Cir. 1998) ("[A] district
    court by definition abuses its discretion when it makes an error
    of law." (quoting Koon v. United States, 
    518 U.S. 81
    , 100 (1996))).
    Thus, while the majority affirms the District Court's decision to
    deny Concepcion's motion for a sentence reduction pursuant to
    § 404(b), I would vacate and remand the District Court's decision
    denying Concepcion § 404(b) relief, so that the District Court may
    consider whether to reduce the sentence on the proper understanding
    that it may consider the impact of the change to the career
    offender Guideline.
    I understand that the District Court on remand might
    well reach the same result -- perhaps based on its reasoning about
    the complexity of any recalculation of the GSR that it invoked in
    discussing Godin/Ahrendt, Concepcion, 
    2019 WL 4804780
    , at *5 &
    n.1.    But, I am hesitant to make that assumption when the District
    Court was misinformed about what § 404(b) itself permitted it to
    do.    Cf. United States v. Taylor, 
    848 F.3d 476
    , 500 (1st Cir. 2017)
    (remanding even upon "recogniz[ing] that [the] sentence on remand
    makes clear that it understood the First Step Act not to permit it
    to consider Amendment 798 as a ground for resentencing under that
    Act.
    - 78 -
    may be unchanged," because "the great latitude possessed by the
    district court . . . makes it all the more important that the
    district judge exercise a fully informed discretion" (quoting
    United States v. Hernandez Coplin, 
    24 F.3d 312
    , 320 (1st Cir.
    1994))).15
    IV.
    Given the deferential standard of review that we must
    apply, in many -- maybe most -- instances concerning § 404(b), the
    legal difference between my approach and the majority's will not
    matter, practically speaking.    In that respect, I agree that there
    is not that much "daylight" between my approach and the majority's.
    Nonetheless, Concepcion's case does illustrate how this
    legal difference might very well matter in some instances.       Cf.
    Godin, 522 F.3d at 136; Frates, 896 F.3d at 103-04.    And, in cases
    involving intervening factual developments, I would think the
    legal difference might be especially significant.
    15Because I find the District Court's error here to inhere
    in its misunderstanding about its discretion to consider
    intervening legal developments, this case does not pose the
    distinct question whether it would be permissible for a district
    court   to   refuse   categorically    to   consider    intervening
    developments, while understanding that it had the legal authority
    to do so.    I do note, though, that this Court's decision in
    Rodríguez-Rosado, 909 F.3d at 481, though also not addressing a
    categorical refusal, did hold that district courts are not required
    to consider post-sentencing rehabilitation in § 3582(c)(2)
    sentence modification proceedings, even while recognizing that
    such evidence can be relevant to the § 3553(a) analysis.
    - 79 -
    Thus,   while   I   do    not     agree   with   the    majority's
    disposition in this case, I also wish to emphasize my broader
    concern about construing the First Step Act in a manner that
    diminishes its remedial impact.        This measure represents a rare
    instance in which Congress has recognized the need to temper the
    harshness of a federal sentencing framework that is increasingly
    understood to be much in need of tempering.            Indeed, the First
    Step Act's very title signals Congress's interest in having more
    rather than less done in that regard going forward.              Accordingly,
    given that the text of § 404(b) is less than clear in the relevant
    respect, I see no reason to construe it in a way that would
    attribute to Congress an intent to constrain district courts from
    exercising the remedial discretion that they are accustomed to
    exercising when revisiting a sentence that may have been too harsh
    when first imposed.   I thus respectfully dissent.
    - 80 -