United States v. Nicholson , 721 F.3d 1236 ( 2013 )


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  •                                                                      FILED
    United States Court of Appeals
    Tenth Circuit
    July 12, 2013
    PUBLISH                   Elisabeth A. Shumaker
    Clerk of Court
    UNITED STATES COURT OF APPEALS
    TENTH CIRCUIT
    UNITED STATES OF AMERICA,
    Plaintiff-Appellee,
    v.                                                    No. 11-2169
    JESSE W. NICHOLSON,
    Defendant-Appellant.
    Appeal from the United States District Court
    for the District of New Mexico
    (D.C. No. 2:10-CR-03163-RB-1)
    Gregory J. Garvey, Assistant Federal Public Defender, Office of the Federal
    Public Defender for the District of New Mexico, Las Cruces, New Mexico, for
    Defendant-Appellant.
    Jessica Cárdenas Jarvis, Assistant United States Attorney, (Kenneth J. Gonzales,
    United States Attorney, and John Grasty Crews, Assistant United States Attorney,
    on the brief), Office of the United States Attorney, District of New Mexico, Las
    Cruces, New Mexico, for Plaintiff-Appellee.
    Before BRISCOE, Chief Judge, McKAY and GORSUCH, Circuit Judges.
    BRISCOE, Chief Judge.
    Defendant Jesse W. Nicholson appeals the district court’s denial of his
    motion to suppress evidence. He appeals after entering a conditional guilty plea
    to three drug and weapons-related charges. We reverse the district court’s ruling
    on the motion to suppress and remand with directions to vacate Nicholson’s
    convictions.
    I
    Midday June 17, 2010, defendant Jesse Nicholson stopped at a red light at
    the busy intersection of 19th Street and Main Street in Roswell, New Mexico.
    Nicholson was in a left-turn lane, planning to turn from eastbound 19th Street and
    enter northbound Main Street. Roswell Police Department Officer Doyle Baker
    was in his vehicle behind Nicholson. Main Street has multiple lanes in each
    direction.
    When the traffic light changed to permit a left turn, Nicholson made a left
    turn into Main Street’s outermost (i.e. right, northbound) lane. He did so, he
    says, to reach a business near the intersection. He proceeded in this fashion so he
    would not impede traffic when he made a quick shift into the right lane to enter
    the parking lot. The intersection had no markings or instructions to indicate that
    a driver must maintain and complete a turn by remaining in the left lane.
    But according to Officer Baker, Nicholson was insufficiently cautious in
    making his left turn. Baker testified that by Nicholson’s completing his turn in
    the right lane he cut off cars making right-hand turns on a red light from
    -2-
    westbound 19th Street onto Main Street’s outermost, northbound lane. 1 Baker
    stopped Nicholson, believing Nicholson’s failure to enter the left lane when
    completing his left turn violated Roswell ordinance 12-6-5.1. Smelling marijuana
    as he approached the vehicle, Baker asked Nicholson to step out of the car. As
    Nicholson complied with this request, Baker spotted two glass pipes—commonly
    used for smoking methamphetamine—and a police scanner in the driver’s door
    pocket. Baker asked for consent to search the vehicle; Nicholson refused.
    Officer Baker released Nicholson after issuing a traffic citation, but seized the
    car.
    Police towed the car and also sought a search warrant. After receiving and
    executing the search warrant, they discovered “various items, including over fifty
    grams of methamphetamine hidden underneath the dashboard, a loaded .40 caliber
    pistol, a scale, assorted pills, marijuana seeds, small plastic baggies, and a small
    notebook with items written down in it.” ROA Vol. I at 20-21.
    Procedural Background
    A grand jury subsequently returned a three-count indictment against
    Nicholson based on the items found in the car. Count 1 of the indictment charged
    Nicholson with unlawfully, knowingly and intentionally possessing with intent to
    distribute 50 grams and more of a mixture and substance containing a detectable
    1
    We note, however, that under N.M. Stat. Ann. § 66-7-105(C), any cars
    making a right turn on red needed to “yield the right-of-way to all pedestrians and
    vehicles lawfully or approaching the intersection.”
    -3-
    amount of methamphetamine in violation of 21 U.S.C. § 841(a)(1) and (b)(1)(B),
    and 18 U.S.C. § 2. Count 2 of the indictment charged Nicholson, a convicted
    felon, with knowingly possessing a firearm in violation of 18 U.S.C. §§922(g)(1)
    and 924(a)(2). Count 3 of the indictment charged Nicholson with knowingly
    carrying a firearm during and in relation to a drug trafficking crime in violation of
    18 U.S.C. § 924(c)(1)(A)(i).
    Nicholson filed a motion to suppress the evidence obtained from the traffic
    stop. Nicholson argued that N.M. Stat. Ann. § 66-7-322—which is essentially
    analogous to the city ordinance he was cited as violating—did not prohibit the left
    turn he made, and that, as a result, the traffic stop violated his Fourth Amendment
    rights. At the hearing held on the motion to suppress, Nicholson suggested that
    the court should certify the question to the New Mexico Supreme Court if it was
    uncertain about the interpretation of the ordinance. The district court denied this
    request, instead stating “I just have to do the best I can.” ROA Vol. III at 417.
    The court then determined the traffic stop was legal because the ordinance
    prohibited the left turn made by Nicholson. The court then denied Nicholson’s
    motion to suppress.
    The case proceeded to trial in March 2011, but a jury was unable to reach a
    verdict on any count. Nicholson subsequently entered into a conditional plea
    agreement, pleading guilty to all counts, but reserving his right to appeal the
    denial of his motion to suppress. ROA Vol. I at 29-35. Nicholson was sentenced
    -4-
    to 63 months in custody on counts 1 and 2, to be served concurrently, and 60
    months’ custody on count 3, to be served consecutively to the sentences on counts
    1 and 2.
    II
    a. Standard of Review
    When reviewing a denial of a motion to suppress, we review de novo the
    district court’s conclusion that the officer’s actions were reasonable. United
    States v. Burciaga, 
    687 F.3d 1229
    , 1230 (10th Cir. 2012). Considering the
    evidence in the light most favorable to the prevailing party, we defer to the
    district court’s findings on questions of fact, reviewing only for clear error. Id.
    We review questions of law de novo. United States v. Johnson, 
    584 F.3d 995
    ,
    998 (10th Cir. 2009).
    b. Officer Violated the Fourth Amendment by Stopping Nicholson on the
    Basis of    a Turn That was Not Illegal
    The Fourth Amendment requires that a traffic stop be “objectively
    justified” at its inception. United States v. DeGasso, 
    369 F.3d 1139
    , 1143 (10th
    Cir. 2004). That means a traffic stop must be “based on an observed traffic
    violation” or a police officer’s “reasonable articulable suspicion that a traffic or
    equipment violation has occurred or is occurring.” United States v. Eckhart, 
    569 F.3d 1263
    , 1271 (10th Cir. 2009) (quoting United States v. Botero-Ospina, 
    71 F.3d 783
    , 787 (10th Cir. 1995) (en banc)). Although an officer’s mistake of fact
    -5-
    can still justify a probable cause or reasonable suspicion determination for a
    traffic stop, an officer’s mistake of law cannot. United States v. Tibbetts, 
    396 F.3d 1132
    , 1138 (10th Cir. 2005). “[F]ailure to understand the law by the very
    person charged with enforcing it is not objectively reasonable.” Id.
    Nicholson argues Officer Baker made a mistake of law when he stopped
    Nicholson for making a left turn into Main Street’s outermost lane. The district
    court rejected this argument, concluding Roswell traffic ordinance § 12-6-5.1
    prohibited this conduct. We review the district court’s construction of state law
    de novo. DeGasso, 369 F.3d at 1144. The New Mexico Supreme Court has not
    interpreted this provision, so we must instead determine how the New Mexico
    Supreme Court would interpret it were the court to face the issue. Tibbetts, 396
    F.3d at 1137-38.
    Nicholson was stopped and cited for a violation of Roswell traffic
    ordinance § 12-6-5.1, which regulates the position and method of turns. More
    specifically, the officer stopped Nicholson on the assumption that § 12-6-5.1
    requires a driver making a left turn to complete the turn in the leftmost lane. Id. 2
    2
    Although most states require a driver to turn left into the leftmost lane,
    others permit drivers to turn left into any lane. See, e.g., Cal. Veh. Code §
    22100(b) (“After entering the intersection, the left turn shall be made so as to
    leave the intersection in a lane lawfully available to traffic moving in that
    direction upon the roadway being entered . . . .”) (emphasis added); Fla. Stat.
    Ann. § 316.151(b); Tex. Transp. Code Ann. § 545.101(b)(2). But see, e.g., Colo.
    Rev. Stat. Ann. § 42-4-901(b) (“Whenever practicable, the left turn shall be made
    to the left of the center of the intersection so as to leave the intersection or other
    (continued...)
    -6-
    Roswell has adopted the New Mexico Uniform Traffic Code, which includes
    ordinance § 12-6-5.1, set out below:
    12-6-5.1 REQUIRED POSITION AND METHOD OF TURNING AT
    INTERSECTION.
    The driver of a vehicle intending to turn at an intersection shall do so
    as follows:
    A. Both the approach for a right turn and a right turn shall be made
    as close as practicable to the right-hand curb or edge of the street.
    B. At any intersection where traffic is permitted to move in both
    directions on each street entering the intersection, an approach for a
    left turn, except where left-turn provisions are made, shall be made
    in that portion of the right half of the street nearest the center line
    thereof and by passing to the right of such center line where it enters
    the intersection and after entering the intersection the left turn shall
    be made so as to leave the intersection to the right of the center line
    of the street being entered. Whenever practicable the left turn shall
    be made in that portion of the intersection to the left of the center of
    the intersection.
    C. Upon a street with two (2) or more lanes for through traffic in
    each direction, where a center lane has been provided by distinctive
    pavement markings for the use of vehicles turning left from both
    directions, no vehicle shall turn left from any other lane. A vehicle
    shall not be driven in this center lane for the purpose of overtaking or
    passing another vehicle proceeding in the same direction. Any
    maneuver other than a left turn from this center lane will be deemed
    a violation of this section.
    2
    (...continued)
    location in the extreme left-hand lane lawfully available to traffic moving in the
    same direction as such vehicle on the roadway being entered.”); Utah Code Ann.
    § 41-6a-801(2)(b) (“Left turns . . . whenever practicable, shall be made by turning
    onto the roadway being entered in the extreme left-hand lane for traffic moving in
    the new direction . . . .”); Wis. Stat. Ann. § 346.31(3)(c) (“A left turn shall be
    completed so as to enter the intersecting highway in the lane farthest to the left
    which is lawfully available to traffic moving the direction of the vehicle
    completing the left turn.”).
    -7-
    D. At any intersection where traffic is restricted to one (1) direction
    on one (1) or more of the streets, the driver of a vehicle intending to
    turn left at any such intersection shall approach the intersection in
    the extreme left-hand lane lawfully available to traffic moving in the
    direction of travel of such vehicle and after entering the intersection
    the left turn shall be made so as to leave the intersection, as nearly as
    practicable, in the left-hand lane lawfully available to traffic moving
    in such direction upon the street being entered.
    E. No person shall drive across any private or public property,
    including but not limited to parking areas, driveways and service
    station areas, for the purpose of avoiding any traffic control device or
    sign.
    Although the New Mexico Supreme Court has not interpreted this
    provision, the New Mexico Court of Appeals recently concluded the analogous
    state statute, 3 N.M. Stat. Ann. § 66-7-322, did not prohibit the type of left turn
    made by Nicholson. State v. Almeida, 
    253 P.3d 941
    , 943-44 (N.M. Ct. App.
    2011). It noted that Section 66-7-322(B) does not by its text require that a driver
    turn into a specific lane, while other sections which address turns do. Section
    66-7-332(A) requires a driver to enter the rightmost lane when making a right
    turn. Section 66-7-332(D) requires a driver to enter the leftmost lane when
    making a left turn onto or from a one-way street. Id. Reading the statute as a
    whole, the court persuasively reasoned the omission of a restriction in Section
    66-7-322 (B) combined with the detailed requirements in (A) and (D)
    3
    The only differences between the Uniform Traffic Ordinance and the
    state statute (A)-(D) are that the Uniform Traffic Ordinance: 1) uses “street(s)”
    instead of “roadway(s)”; and 2) includes numerals next to numbers written as
    words.
    -8-
    demonstrated the absence of a legislative intent to prohibit left turns into the
    outermost lane when travel on one-way streets is not at issue. Id. at 944.
    Although the government correctly asserts we need not adopt the opinion of
    the intermediate appellate court, see United States v. Valadez-Valadez, 
    525 F.3d 987
    , 993 (10th Cir. 2008), it has advanced no rationale which would justify our
    departing from its reasoning. The court of appeals applied sound methods of
    statutory interpretation, reading the statute as a whole so that it gave effect to all
    of its provisions. Any contrary reading would contravene the legislature’s
    apparent intent, requiring us to read words into the statute which the legislature
    demonstrated it could have, but did not, include. Despite the many statutory
    provisions which regulate turns, none specifically prohibits the method Nicholson
    employed in making his turn. 4 We conclude the traffic ordinance relied upon by
    4
    Although it never explicitly explained its reading of the ordinance in its
    brief, the government at oral argument suggested that the second sentence of §
    12-6-5.1(B) prohibits turns like those made by Nicholson. But, by its text, this
    sentence only regulates the driver’s position while within the
    intersection—presumably to avoid impeding oncoming traffic making left turns in
    the opposite direction—and does not address the proper positioning of the vehicle
    once the driver leaves the intersection. Again, we will not read into the ordinance
    words that could have been included. Statutes in other states with similar
    language regulating left turns specify which lane a driver must turn into. See,
    e.g., Colo. Rev. Stat. Ann. § 42-4-901(b) (“Whenever practicable, the left turn
    shall be made to the left of the center of the intersection so as to leave the
    intersection or other location in the extreme left-hand lane lawfully available to
    traffic moving in the same direction as such vehicle on the roadway being
    entered.”); Neb. Rev. Stat. Ann. § 60-6,159(2) (“[T]he left turn shall be made so
    as to leave the intersection, as nearly as practicable, in the extreme left-hand lane
    lawfully available to traffic moving in such direction upon the roadway being
    (continued...)
    -9-
    Officer Baker did not provide a legal basis for his stop of Nicholson.
    The government insists we should nonetheless uphold the stop because the
    law which served as the basis for Officer Baker’s stop is not “plain and
    unambiguous.” Even assuming the law was unclear, we cannot agree. In our
    circuit, as in most others, mistakes of law made by an officer are objectively
    unreasonable. See Tibbets, 396 F.3d at 1138; see also United States v.
    McDonald, 
    453 F.3d 958
    , 960-62 (7th Cir. 2006) (officer lacked probable cause to
    stop defendant based on mistaken belief defendant violated law by using his
    left-turn signal while going around a bend); United States v. Chanthasouxat, 
    342 F.3d 1271
    , 1278-80 (11th Cir. 2003) (held a mistake of law invalidated a traffic
    stop even though the officer believed the law existed based on training, guidance
    from a magistrate, and the more than 100 tickets he had written citing it); United
    States v. Lopez-Soto, 
    205 F.3d 1101
    , 1106-07 (9th Cir. 2000) (officer lacked
    reasonable suspicion to stop defendant based on mistaken belief about proper
    placement of registration sticker); United States v. Miller, 
    146 F.3d 274
    , 277-79
    (5th Cir. 1998) (officer lacked probable cause to stop defendant based on
    mistaken belief defendant violated law by using turn signal without changing
    4
    (...continued)
    entered. Whenever practicable, the left turn shall be made in that portion of the
    intersection to the left of the center of the intersection.”); N.H. Rev. Stat. Ann. §
    265:42(II)(a) (“Whenever practicable, a left turn shall be made to the left of the
    center of the intersection and so as to leave the intersection or other location in
    the extreme left hand lane lawfully available to traffic moving in the same
    direction as such vehicle on the roadway being entered.”).
    -10-
    lanes or turning); but see United States v. Washington, 
    455 F.3d 824
    , 827 (8th
    Cir. 2006) (instead looking at whether a mistake of law is “objectively
    reasonable”). 5
    As we said in Tibbetts,“failure to understand the law by the very person
    charged with enforcing it is not objectively reasonable.” 
    396 F.3d 1132
     at 1136.
    See also Sherouse v. Ratchner, 
    573 F.3d 1055
    , 1059 (10th Cir. 2009) (“While an
    officer’s reasonable but mistaken understanding of the facts justifying a search or
    seizure does not negate the legitimacy of a probable cause determination, an
    officer’s reasonable but mistaken understanding of the applicable law he is
    enforcing does.”). Nothing in our opinion in Tibbetts suggests we actually meant
    to limit this rule only to the mistaken understanding of “plain and unambiguous
    laws.” 6 In providing the district court with guidance for interpreting the Utah
    5
    We acknowledge, however, that there is considerably more tension
    between state appellate courts as to whether police officer’s “reasonable”
    mistakes of law should be excused. Compare State v. Louwrens, 
    792 N.W.2d 649
    , 650 (Iowa 2010) (“[E]vidence derived from a stop based on a law
    enforcement officer’s mistake of law must be suppressed.”) and State v.
    Anderson, 
    683 N.W.2d 818
    , 823-24 (Minn. 2004) with Moore v. State, 
    986 So. 2d 928
    , 935 (Miss. 2008) (en banc) (“Officer Moulds had sufficient probable cause
    to pull [defendant] over, although, as it turns out, Officer Moulds based his belief
    of a traffic violation on a mistake of law.”) and State v. Heien, 
    737 S.E.2d 351
    (N.C. 2012). See also Dissent Op. at 19-20.
    6
    Although we used the “plain and unambiguous” language in United States
    v. DeGasso, 
    369 F.3d 1139
    , 1144-45 (10th Cir. 2004), there is no indication we
    actually intended to distinguish cases in which the officer makes a mistake about
    a “plain and unambiguous law” from cases involving more murky ones. Instead,
    we were merely describing what actually happened in that case: the officer
    (continued...)
    -11-
    statute at issue we said that “Utah courts look to the plain language of the statute,
    and only when the language is ambiguous do they seek guidance from legislative
    history or policy considerations.” Id. at 1138. This instruction on ambiguity
    seems unnecessary if we only fault police officers when a law is plain and
    unambiguous.
    Despite the dissent’s contention, we come to this conclusion by more than
    just isolating a single sentence of the Tibbetts opinion. Throughout the opinion in
    Tibbetts, we also took care to distinguish the difference between mistakes of fact
    and mistakes of law—something that only matters if we treat them differently.
    Cf. United States v. Smart, 
    393 F.3d 767
    , 770 (8th Cir. 2005) (“In any case, in
    our circuit the distinction between a mistake of law and a mistake of fact is
    irrelevant to the fourth amendment inquiry.”). That is, we excuse reasonable
    mistakes of fact, but not “reasonable” mistakes of law. Remand to determine the
    question of whether the officer had made a mistake of fact or a mistake of law
    would have been unnecessary in Tibbetts if we applied a reasonableness analysis
    to both types of mistakes.
    Moreover, we said that on remand “the district court must determine
    whether [Sergeant] Chugg had a reasonable articulable suspicion of a violation of
    6
    (...continued)
    stopped the defendant for driving with fog lamps on during the day when
    Oklahoma law clearly only prohibited the use of fog lamps as a substitute for
    headlamps at night. Id. at 1144.
    -12-
    Utah’s ‘mudflap’ law in light of the facts as Chugg observed them, or whether
    Chugg simply misunderstood the law.” 396 F.3d at 1137 (emphasis added). Later
    we said “[w]e have consistently held that an officer’s mistake of fact, as
    distinguished from a mistake of law, may support probable cause or reasonable
    suspicion.” Id. at 1138 (emphasis added). Finally, we instructed the district court
    on remand to “determine whether Chugg’s belief that the law was violated
    because the mudflaps did not fully cover the wheels was correct, a reasonable
    mistake of fact, or an impermissible mistake of law.” Id. at 1139. Notably, we
    did not give the district court the option of deciding whether the officer made a
    “permissible” mistake of law.
    Further, as we have acknowledged, requiring law enforcement personnel to
    know the law they are asked to enforce comports with a basic policy of fairness.
    If “[a]s a rule, . . . a defendant is presumed to know the law, we must expect as
    much from law enforcement.” United States v. Orduna-Martinez, 
    561 F.3d 1134
    ,
    1137 n.2 (10th Cir. 2009). Permitting officers to excuse their mistakes of
    substantive law as “reasonable” “would remove the incentive for police to make
    certain that they properly understand the law that they are entrusted to enforce
    and obey.” United States v. Lopez-Soto, 
    205 F.3d 1101
    , 1106 (9th Cir. 2000). In
    addition, although the dissent repeatedly refers to our decision as creating a
    “new” rule of constitutional law, the outcome we propose here places us in accord
    with the vast majority of our sister circuits—whose decisions we have repeatedly
    -13-
    cited to in our earlier opinions. See Orduna-Martinez, 561 F.3d at 1137 n.2
    (“Other circuits have held that a trooper’s reasonable mistake of law cannot make
    an otherwise impermissible stop reasonable. In agreement with these circuits, we
    have held that failure to understand the law by the very person charged with
    enforcing it is not objectively reasonable.”) (citations and quotations omitted);
    see, e.g., Tibbetts, 396 F.3d at 1138 (citing United States v. Miller, 
    146 F.3d 274
    (5th Cir. 1998)); DeGasso, 369 F.3d at 1144-45 (citing United States v.
    Chanthasouxat, 
    342 F.3d 1271
     (11th Cir. 2003)). Given this precedent, we hold
    the Officer Baker’s actions were unreasonable whether or not the ordinance was
    “plain and unambiguous.”
    Although we are bound by circuit precedent, we must also point out that
    any fears that this rule is too restrictive are overstated. Because we retain an
    objective, totality of the circumstances analysis, actions taken based on a
    subjective misunderstanding of the law will still, in some circumstances, be
    considered reasonable. 7 We would not, for instance, hold unreasonable the
    actions of an officer who pulled over a motorist driving 75 miles per hour in a 55-
    mile-per-hour zone, even if the officer himself believed the speed limit was 65
    miles per hours. Cf. United States v. Wallace, 
    213 F.3d 1216
    , 1220 (9th Cir.
    2000) (initial stop justified where the officer’s “observations correctly caused him
    7
    As the Fifth Circuit has pointed out, it is precisely because of the leeway
    we normally grant police officers that “the legal justification must be objectively
    grounded.” Miller, 146 F.3d at 279 (5th Cir. 1998).
    -14-
    to believe that Wallace’s window tinting was illegal” although he was “wrong
    about exactly why”). Indeed, we will uphold a traffic stop as long as there was
    reasonable suspicion to stop the defendant for “‘any one of the multitude of
    applicable traffic and equipment regulations’ of the jurisdiction.” United States
    v. Botero-Ospina, 
    71 F.3d 783
    , 787 (10th Cir. 1995) (en banc) (quoting Delaware
    v. Prouse, 
    440 U.S. 648
    , 661 (1979)).     See also Eckhart, 569 F.3d at 1271 (10th
    Cir. 2009) (upholding traffic stop despite officer’s mistake of law because officer
    had reasonable suspicion to stop vehicle for another related violation of Utah
    law); United States v. Eckhart, No. 2:05CR529DAK, 
    2006 WL 1073465
    , at *3 (D.
    Utah Apr. 10, 2006) (state trooper testifying incorrectly about requirements of
    Utah law). So although a defendant need only violate one provision of a vast
    number of local, state, and federal laws to trigger criminal liability, police
    officers can argue they had reasonable suspicion to stop a defendant based on any
    of those laws—even if the officer was mistaken about the specific law he thought
    the defendant was violating. A single mistake by a law enforcement officer will
    not necessarily invalidate the stop and any resulting search.
    Law enforcement officials have another advantage over
    citizens—they can, in some circumstances, seek a warrant to confirm their belief
    about the interpretation of a statute. True, as the dissent points out, “obscure
    regulatory edicts” may exist. See Dissent Op. at 16. But we also cannot imagine
    many circumstances where a law enforcement official would need to execute a
    -15-
    warrantless search based on someone violating one of those regulations. Even if
    we held the subsequent search unreasonable because the judge also misinterpreted
    the law, our good faith precedent would likely provide an exception to the
    exclusionary rule. Moreover, one would hope that a law enforcement official
    would clarify his understanding of any unclear provision before bringing the full
    force of the law upon an unsuspecting citizen.
    While we acknowledge that the Supreme Court has excused other mistakes
    made by police officers, none of its rationales for excusing those mistakes apply
    to mistakes of substantive law. The Supreme Court has excused an officer’s
    mistake regarding the constitutionality of a law because the police must usually
    assume the legislature will only pass laws that are constitutional. See Michigan
    v. DeFillippo, 
    443 U.S. 31
    , 38 (1979) (“The enactment of a law forecloses
    speculation by enforcement officers concerning its constitutionality—with the
    possible exception of a law so grossly and flagrantly unconstitutional that any
    person of reasonable prudence would be bound to see its flaws.”). Police officers
    have a duty “to enforce laws until and unless they are declared unconstitutional.”
    Id. “If the statute is subsequently declared unconstitutional, excluding evidence
    obtained pursuant to it prior to such a judicial declaration will not deter future
    Fourth Amendment violations by an officer who has simply fulfilled his
    responsibility to enforce the statute as written.” Illinois v. Krull, 
    480 U.S. 340
    ,
    350 (1987). Indeed, “[s]ociety would be ill-served if its police officers took it
    -16-
    upon themselves to determine which laws are and which are not constitutionally
    entitled to enforcement.” DeFillippo, 443 U.S. at 38. The same reliance
    argument does not apply to mistakes about substantive law.
    Additionally, we permit reasonable mistakes of fact because “sufficient
    probability, not certainty, is the touchstone of reasonableness under the Fourth
    Amendment . . . .” Hill v. California, 
    401 U.S. 797
    , 804 (1971). But the Supreme
    Court has also specifically noted that this reasonableness analysis applies to
    “factual judgments that law enforcement officials are expected to make.” Illinois
    v. Rodriguez, 
    497 U.S. 177
    , 184 (1990) (emphasis added). A totality of the
    circumstances approach makes sense in this factfinding role, because officers can
    exercise their judgment based on their experience and common sense. United
    States v. Cortez, 
    449 U.S. 411
    , 418 (1981) (“[T]he evidence . . . must be seen and
    weighed not in terms of library analysis by scholars, but as understood by those
    versed in the field of law enforcement.”). “Because many situations which
    confront officers in the course of executing their duties are more or less
    ambiguous, room must be allowed for some mistakes on their part.” Brinegar v.
    United States, 
    338 U.S. 160
    , 176 (1949). Officers with reasonable suspicion
    often have no way to confirm a violation has been committed without further
    investigation. Cf. United States v. Cashman, 
    216 F.3d 582
    , 587 (7th Cir. 2000)
    (“A trooper in Spetz’s position, then, passing or approaching [defendant]’s
    vehicle on the roadway, could readily and reasonably think that the crack [in the
    -17-
    windshield] met the administrative criteria for excessive cracking . . . [even
    though] careful measurement after the fact might reveal that the crack stopped
    just shy of the threshold for ‘excessive’ cracking or damage[.]”). But this need to
    make probabilistic judgments about the relevance of facts does not transfer to the
    interpretations of laws, of which officers can learn a definitive meaning before
    acting.
    Finally, reformulating the legal question at issue in this case will likely
    clear up many of the dissent’s remaining uncertainties. The term “mistake of
    law” is somewhat misleading, as it is ultimately irrelevant what law the officer
    thought the defendant was violating. See Devenpeck v. Alford, 
    543 U.S. 146
    , 153
    (2004) (“Our cases make clear that an arresting officer’s state of mind (except for
    the facts that he knows) is irrelevant to the existence of probable cause.”). The
    relevant question, in a case such as this one, is: Against what interpretation of
    the law should we assess the facts when deciding whether there was reasonable
    suspicion or probable cause to make a traffic stop? Like most of our sister
    circuits, we judge the facts against the correct interpretation of the law, as
    opposed to any other interpretation, even if arguably a reasonable one. 8
    This reformulation likely clarifies the result in many of the borderline cases
    8
    That is, jurisdictions that permit “reasonable” mistakes of substantive law
    require courts to assess whether there are also any incorrect (but reasonable)
    interpretations of our laws that might justify the government’s assertion that an
    officer had observed sufficient facts to establish reasonable suspicion or probable
    cause.
    -18-
    cited by the dissent. 9 In the case of a local ordinance that conflicted with state
    law, an officer would likely be reasonably justified in relying on the local
    ordinance based on the reliance principles set forth in the Supreme Court’s cases
    analyzing mistakes regarding the constitutionality of the law. And some mistakes
    of law—say as to legal ownership—might nonetheless be excused as being closer
    to a mistake of fact, as they are not the substantive law upon which the officer is
    basing his reasonable suspicion or probable cause determination. Finally, we
    reiterate that we will uphold traffic stops as long as the law enforcement officer
    cites particularized facts that show he could have had a reasonable suspicion that
    any law was being violated.
    III
    The government argues that we should nonetheless affirm the district court
    because either (a) another legal basis existed for Officer Baker stopping or citing
    Nicholson, or (b) the good faith exception first recognized in United States v.
    Leon, 
    468 U.S. 897
     (1984), should be applied in this case. The litigation history
    of this case, however, precludes us from doing so.
    In its written response to Nicholson’s motion to suppress, the government
    argued that “Officer Baker had reasonable suspicion to conduct a traffic stop,”
    9
    While the dissent characterizes these as “exceptions” to our rule, this
    again appears to be premised on the fact courts have misleadingly titled this as a
    rule about “mistakes of law.” All the prevailing rule purports to do is require
    courts make probable cause determinations by assessing the facts against the
    correct interpretation of the law.
    -19-
    ROA Vol. I at 15, because he “observed [Nicholson’s vehicle] fail to maintain the
    inside left lane as it was turning and cut in front of traffic,“ id. at 12. No other
    violation was mentioned, and the good faith exception under Leon was not
    asserted in the alternative. At the subsequent hearing on Nicholson’s motion,
    Baker testified on direct examination, in consistent fashion with the government’s
    arguments in its written response, that he observed Nicholson’s vehicle “fail[] to
    maintain the inside left lane turning to the right-hand lane, cutting off traffic” in
    that lane. ROA Vol. III at 361. Later on in his direct examination, Baker
    testified that the basis for his stop of Nicholson, as well as the ensuing citation he
    issued to Nicholson, was “fail[ure] to maintain inside left lane while turning,”
    which Baker described as a violation of both “State [and] City ordinance[s].” Id.
    at 370. During defense counsel’s cross-examination of Baker, the district court
    asked Baker to clarify his previous testimony:
    THE COURT: Let me clarify something: How many violations
    are there here on this page that you saw?
    THE WITNESS: How many violations?
    THE COURT: Yes. I mean, are there one or two or more or just
    none, whatever. You ticketed him for one violation?
    THE WITNESS: Yes, sir.
    THE COURT: Is that all the violations that you saw?
    THE WITNESS: Yes, sir.
    THE COURT: All right. Now, as I look at this picture [of the
    intersection], is the violation occurring on Main Street on the
    northbound lane? No. Main Street is going north right?
    THE WITNESS: Yes, sir.
    THE COURT: Is the violation occurring on Main Street when he
    doesn’t come behind the white car or is the violation occurring on
    19th as he moves, perhaps, into the outside lane of 19th?
    -20-
    THE WITNESS: It’s where he fails to maintain the left lane.
    ***
    THE COURT: Okay. So it’s not a matter of him bulging out into
    the right-hand lane as he was on 19th?
    THE WITNESS: No, sir.
    THE COURT: It’s a matter of him swinging out into the outside
    lane on Main Street as he goes north?
    THE WITNESS: Yes, sir. It he would have came into the
    interseciton wide and still maintained the left-hand lane, he would
    have been fine. It’s the failing to maintain the left lane, crossing into
    the right lane, is the violation.
    Id. at 379-80. And during recross-examination, Officer Baker quoted the
    provision of the ordinance he cited Nicholson with violating and then testified,
    “To me, that’s saying that you need – the left turn shall be made to the left of the
    intersection maintaining the left lane. He [Nicholson] failed to do that.” Id. at
    390.
    As discussed above, we will uphold a traffic stop as lawful on the basis of
    any traffic violation for which the facts known to the officer established
    reasonable suspicion, even when the officer did not cite that provision of the
    traffic code when making the traffic stop. But at no point during the hearing did
    the government argue the existence of any other traffic violation that would have
    supported Baker’s stop of Nicholson. And although the government now argues
    for the first time on appeal that Officer Baker could have cited Nicholson for
    careless driving, there is no factual basis in the record for such a determination,
    even if we were inclined to overlook the government’s failure to assert this
    argument below.
    -21-
    As for the good faith exception, the government made no mention of it
    during the district court proceedings and raises it for the first time in its appellate
    response brief. Typically, “[i]ssues and arguments which are not raised below
    will not ordinarily be considered on appeal.” Mann v. United States, 
    204 F.3d 1012
    , 1017 (10th Cir. 2000). To be sure, “[w]e are free to affirm a district court
    decision on any grounds for which there is a record sufficient to permit
    conclusions of law, even grounds not relied upon by the district court.” United
    States v. Sandoval, 
    29 F.3d 537
    , 542 n.6 (10th Cir. 1994). But the government’s
    failure to raise this issue in district court means the parties developed no record
    evidence on this point. Therefore, even were we to reject Nicholson’s argument
    that the good faith exception does not apply as a matter of law, there is no support
    in the record for affirming the district court on the government’s theory. See
    Dissent Op. at 21. (“Trying to administer the cost-benefit analysis [of the
    exclusionary rule] without the benefit of the district court’s factual findings on
    the relevant questions makes a tough task tougher still.”).
    Nor is there, as the dissent urges, any basis for remanding the case for
    further factual findings on this issue. We have often instructed district courts to
    vacate convictions upon our reversing the denial of a motion to suppress. See,
    e.g., United States v. Neff, 
    681 F.3d 1134
    , 1143 (10th Cir. 2012); United States v.
    Benard, 
    680 F.3d 1206
    , 1215 (10th Cir. 2012); United States v. Trestyn, 
    646 F.3d 732
    , 744 (10th Cir. 2011). We see no reason the government should receive the
    -22-
    benefit of relitigating this motion as a result of its own failure to raise an issue in
    district court.
    IV
    We REVERSE the district court’s denial of the motion to suppress and
    REMAND with directions to vacate Nicholson’s convictions.
    -23-
    11-2169, United States v. Nicholson
    GORSUCH, J., Circuit Judge, dissenting.
    What should the court do when an officer detains an individual based on
    what later turns out to be a mistaken — but reasonable — belief that the law’s
    been broken? My colleagues suggest that an investigative detention resting on an
    officer’s mistake of law always violates the Fourth Amendment — even when the
    law at issue is deeply ambiguous and the officer’s interpretation entirely
    reasonable. Having found a Fourth Amendment violation, they proceed to order
    the suppression of all evidence found during the detention and direct the dismissal
    of all charges. Respectfully, I have my doubts.
    I
    Jesse Nicholson was in a hurry. Instead of finishing his left turn onto Main
    Street in the inside lane near the median, Mr. Nicholson steered into the outside
    lane near the curb. Aiming to do a little shopping on that side of the street, Mr.
    Nicholson no doubt sought to save himself the trouble of a lane change and make
    his way to the store the faster for it.
    Spotting Mr. Nicholson’s maneuver, Officer Doyle Baker was none too
    pleased. He thought it violated the traffic code. As he understood the law, New
    Mexico drivers have to complete left turns in the inside lane of any road they
    enter that happens to bear multiple lanes. Mr. Nicholson didn’t do that, and
    what’s worse, by entering the outside lane instead he may have “cut off” another
    car trying to turn right. Here’s how Officer Baker later depicted the scene:
    After stopping Mr. Nicholson’s car and while approaching the driver’s window to
    issue a ticket, Officer Baker encountered a waft of burning marijuana spilling
    from the vehicle. A warrant application soon followed and then a search of Mr.
    Nicholson’s car, a search that yielded not just marijuana but methamphetamine,
    an unlawful handgun, various pills — and now this litigation.
    -2-
    Before the district court, Mr. Nicholson’s motion to suppress got him
    nowhere. He argued that evidence about the drugs and gun in his car should be
    excluded from any criminal proceedings against him because his traffic stop was
    unlawful. The government replied that the state traffic code required him to enter
    the inside lane after finishing his left turn, just as Officer Baker thought. With
    this the district court agreed, holding that “Officer Baker properly interpreted the
    [traffic code]. . . . [and] the stop was valid.”
    Only then did this seemingly simple case take a more complicated turn. As
    Mr. Nicholson prepared to appeal the district court’s ruling, a divided panel of
    New Mexico’s intermediate appellate court ruled in a separate case that the traffic
    code doesn’t require left turners to enter the inside lane. See State v. Almeida,
    
    253 P.3d 941
    , 944 (N.M. Ct. App. 2011). Though we aren’t bound to accept that
    interpretation, though it came over a dissent, though the court today assumes New
    Mexico’s left turn law is ambiguous, see Maj. Op. at 9, though many other states
    do have laws against the maneuver, see id. at 8 n.4, I agree with my colleagues
    that Almeida still has the better reading of the New Mexico traffic code, at least
    as it’s currently constructed. So with the benefit of more than a little hindsight,
    we all agree Officer Baker, like the very able district court, made a mistake in
    reading the traffic code.
    The question we face is what to do about it.
    -3-
    II
    A
    Instead of setting forth exact limits of the government’s search and seizure
    powers in some numbingly detailed (and no doubt quickly antiquated) list of do’s
    and don’ts, the framers of the Fourth Amendment more simply and ingeniously
    forbade all “unreasonable searches and seizures.” U.S. Const. amend IV. In
    asking what triggers this test, in asking whether the government has acted
    reasonably, we must usually examine with care “the totality of the circumstances”
    or “the whole picture” of the case before us. United States v. Sokolow, 
    490 U.S. 1
    , 8 (1989). Rarely do we expect the Fourth Amendment’s reasonableness
    standard to yield “readily, or even usefully, . . . a neat set of legal rules,”
    Sokolow, 490 U.S. at 7, or “bright-line tests [or] mechanistic inquiries,” Florida
    v. Harris, 
    133 S. Ct. 1050
    , 1055 (2013). Instead, by the very way it is written the
    Fourth Amendment more often requires us to assess the government’s actions in
    each case as it comes to us against “commonsense, nontechnical conceptions that
    deal with the factual and practical considerations of everyday life on which
    reasonable and prudent men, not legal technicians, act.” Ornelas v. United States,
    
    517 U.S. 690
    , 695 (1996) (internal quotation marks omitted). By its terms, the
    Fourth Amendment seems to favor a case-by-case approach, one sensitive to the
    totality of the circumstances found in the case at hand, one that takes a realistic
    -4-
    view of human capacities and limitations. Illinois v. Rodriguez, 
    497 U.S. 177
    ,
    185 (1990).
    I don’t doubt that many searches and seizures initiated because of an
    officer’s mistake about the law — because of a mistaken belief that a law
    proscribes the defendant’s conduct when none does — should be held
    unreasonable and so unconstitutional. Especially when the circumstances tend to
    suggest that the law is unambiguous, the error plain, the officer’s actions
    inconsistent with his training or common sense. At the same time, it seems to me
    we just don’t know enough yet about the totality of the circumstances surrounding
    Officer Baker’s mistake in this case to assess its reasonableness (or lack of
    reasonableness) with any degree of confidence. We don’t because the district
    court rested its decision on the (in hindsight, itself mistaken) view that Officer
    Baker read the traffic code correctly and thus simply had no reason to reach the
    question.
    To be sure, we do know some important things about Officer Baker’s
    conduct. With the benefit of Almeida, we know Officer Baker erred in his
    reading of the traffic code. But we also know that Officer Baker acted before
    Almeida issued; that no New Mexico authority rejected his interpretation of the
    traffic code at the time of the stop; that many other states hold unlawful turns like
    Mr. Nicholson’s; and that the mistake the officer made about the meaning of New
    Mexico’s traffic code was one the very able district judge and a dissent in
    -5-
    Almeida made as well. We know, as well, that we live in a world where some
    laws are ambiguous and don’t admit an easy or even a single right answer, where
    interpretations of legal texts can be reasonable even though they may not be the
    ones we would choose. We recognize this reality in a whole array of contexts.
    See, e.g., Pearson v. Callahan, 
    555 U.S. 223
    , 231 (2009) (qualified immunity);
    Williams v. Taylor, 
    529 U.S. 362
    , 410 (2000) (habeas); Chevron, U.S.A., Inc. v.
    Nat. Res. Def. Council, Inc., 
    467 U.S. 837
    , 843 & n.11 (1984) (administrative
    law). And we know that the majority today proceeds on the assumption that the
    left turn law at issue before us is indeed an ambiguous one. Maj. Op. at 9.
    But beyond these few things, we know little. We don’t know, for example,
    whether law enforcement officers in New Mexico typically share Officer Baker’s
    understanding that left turns into right lanes are illegal, whether Officer Baker
    relied on police training in thinking as much, or even whether as a practical and
    commonsensical matter a good many New Mexicans share Officer Baker’s
    skepticism about the legality of left turns into outside lanes. And this isn’t to say
    additional fact-finding could only help the government’s case. We also know
    nothing about the quality of any training Officer Baker received or the
    reasonableness of any decision Officer Baker made to rely on it. Or whether,
    perhaps, he just assumed that Mr. Nicholson’s maneuver had to be illegal.
    At this stage, then, it seems to me we can only guess about the totality of
    the circumstances, the “factual and practical considerations of everyday life,”
    -6-
    relevant to this case; and only guess, too, about how those considerations might
    inform a decision on the dispositive question whether a “reasonable and prudent”
    officer would have acted as Officer Baker did in the circumstances he faced.
    Ornelas, 517 U.S. at 695. Rather than guess, I would allow the district court,
    with its fact-finding powers, the chance to take up those questions in the first
    instance. In this appeal, I would simply correct the district court’s mistake about
    New Mexico’s traffic law and remand the case to the district court for its
    reconsideration in that new light. Any decision this court might eventually be
    called on to make after remand would in this way be better informed by the
    relevant facts the district court alone can develop — and it would in this way
    benefit, too, from the district court’s considered judgment based on a correct
    understanding of the traffic code.
    B
    Instead of resting at this modest destination, my colleagues press on to a
    more ambitious one. Rather than correct the district court’s legal error and
    remand for further investigation into the reasonableness or unreasonableness of
    Officer Baker’s mistake in that new light, they proceed to hold categorically that
    an officer mistake of substantive law always violates the Fourth Amendment.
    They say “reformulating the legal question at issue in this case will likely clear
    up” any confusion why this new rule of constitutional law is necessary. Maj. Op.
    at 16. But their reformulation only makes plain their view that it’s “irrelevant”
    -7-
    whether the officer’s interpretation of the law was or was not “arguably a . . .
    reasonable one.” Id. at 17 (emphasis added). In the court’s view, an officer’s
    stop or search resting on a mistaken interpretation of substantive law always
    violates the Fourth Amendment — even if the law is confoundingly opaque and
    the mistake one entirely reasonable people would make. Id. at 10.
    Not only do I find it unnecessary to go so far to resolve this appeal, I worry
    about the destination. The court today seems to take us to places the Supreme
    Court has warned us against and to drive us into the maw of a circuit split.
    For starters, my colleagues’ new categorical rule is hard to reconcile with
    the Fourth Amendment’s language and the Supreme Court’s general approach to
    it. As we’ve seen, our constitutionally assigned task is to assess the
    reasonableness of governmental conduct. In performing that job, we are usually
    told to be sensitive to the totality of the circumstances, to view rigid rules with a
    degree of skepticism, to ask what reasonably prudent people do and think and not
    how legal technicians might. Yet a legal technician’s rigid rule seems exactly
    what the court adopts today. Under the court’s approach, it doesn’t matter that
    the law is ambiguous and it doesn’t matter whether the facts on remand might
    show that most people in New Mexico read the law as Officer Baker did, that
    officers were trained to read it that way, or even that many experts agreed with
    this reading. Under the court’s approach, it simply doesn’t matter how “arguably
    . . . reasonable,” Maj. Op. at 17, Officer Baker’s mistake turns out to be in light
    -8-
    of the totality of the circumstances: the fact that we “legal technicians” later
    (much later) find his interpretation in error is enough to be sure he violated the
    Fourth Amendment.
    My colleagues’ categorical approach is in tension, too, with the Supreme
    Court’s even more specific directions about how we should treat officer errors in
    Fourth Amendment cases. It is long settled, for example, that “[a] traffic stop
    based on an officer’s incorrect but reasonable assessment of the facts does not
    violate the Fourth Amendment.” United States v. Tibbetts, 
    396 F.3d 1132
    , 1138
    (10th Cir. 2005) (emphasis added);`` see also Hill v. California, 
    401 U.S. 797
    ,
    803-04 (1971). Exactly the same holds true for officer mistakes in interpreting
    the Constitution’s commands: only unreasonable mistakes offend the Fourth
    Amendment; reasonable mistakes are routinely upheld. See Michigan v.
    DeFillippo, 
    443 U.S. 31
    , 37-38 (1979). Whether we are facing a mistake of fact
    or constitutional law, then, we’ve been told to employ the traditional totality of
    the circumstances approach. It is unclear to me how or why we might single out
    officer mistakes of substantive law and adopt for them alone a new categorical
    Fourth Amendment rule alien to the treatment of all other species of officer
    mistakes. Not to mention when the Supreme Court and we already recognize that
    mistakes of substantive law can be and are reasonable in so many other contexts
    (qualified immunity, collateral review, administrative law, to name just a few).
    -9-
    For its part, the court today doesn’t dispute that all other kinds of officer
    mistakes are addressed under a totality of the circumstances approach in the
    Fourth Amendment context. It doesn’t dispute the adequacy of that traditional
    approach to protect Fourth Amendment values when it comes to other kinds of
    officer mistakes. It doesn’t dispute that we have long recognized in other
    doctrinal areas that mistakes of substantive law sometimes may be reasonable.
    Instead, it seeks to single out mistakes of substantive law alone and devise a new
    categorical rule of Fourth Amendment law for them alone.
    But what the court today doesn’t do is tell us why its course is necessary.
    To be sure, the court does tell us that mistakes of constitutional law are different
    from mistakes of substantive law. Different because officers may assume the
    legislature will pass only laws that are constitutional, while this same “reliance
    argument does not apply to mistakes about substantive law.” Maj. Op. at 15. The
    difficulty is, the court never explains how this observation compels its new rule.
    We might all agree that officers are usually entitled to assume the
    constitutionality of the substantive laws they are hired to enforce, just as the court
    says. But it’s unclear why this observation necessitates a new categorical rule
    holding officer mistakes of substantive law always violate the Fourth Amendment
    — why the usual totality of the circumstances approach isn’t inappropriate in this
    single arena. The court just doesn’t say.
    - 10 -
    Perhaps the court’s unspoken premise is that constitutional law errors are
    categorically forgiven so an inverse categorical rule condemning substantive law
    errors is unremarkable. But if that’s the premise, it is a faulty one. The Supreme
    Court has never said we should categorically forgive officer errors of
    constitutional law. Surely, after all, some constitutional standards are so
    blindingly clear and some statutes so blindingly unconstitutional that an officer
    enforcing those statutes would be unreasonable because “any person of reasonable
    prudence would be bound to see [their] flaws.” DeFillippo, 443 U.S. at 38. An
    officer’s general ability to rely on the constitutionality of a legislature’s
    enactments, then, is not exceptionless but merely serves as one consideration or
    input in the usual totality of the circumstances inquiry.
    Turning to officer mistakes of fact, my colleagues say the usual totality of
    the circumstances approach is appropriate there because officers sometimes must
    make “probabilistic judgments” about uncertain factual scenarios “based on their
    experience and common sense,” judgments that may well be reasonable even if
    they later turn out to be wrong. Maj. Op. at 15-16. Meanwhile, my colleagues
    reason, “this need to make probabilistic judgments . . . does not transfer to the
    interpretations of laws.” Id. at 16.
    Once again, however, my colleagues don’t explain what difference their
    distinction makes. Even assuming officers never need to make probabilistic
    judgments about substantive laws, the court does not tell us why this warrants its
    - 11 -
    unusual new rule, why the usual totality of the circumstances approach can’t do
    the job equally well.
    Neither, once again and in any event, is the court’s premise correct.
    Officers sometimes do have to make probabilistic judgments not just about facts
    but also about whether the conduct they witness while on patrol falls within the
    scope of an ambiguous legal code. Judgments that may not be vindicated as
    correct in retrospect but that may be reasonable at the time. In qualified
    immunity cases we have long recognized that officers sometimes must and do
    make probabilistic judgments about ambiguous laws and we hold them civilly
    liable only when their judgments are foreclosed by clearly established law. In
    habeas and administrative law, we recognize that state courts and administrative
    agencies must sometimes make probabilistic judgments about ambiguous laws,
    and we usually decline to reverse them so long as their judgments are at least
    reasonable. It is altogether unclear why we would in the Fourth Amendment
    context alone ignore the reality that probabilistic judgments are and must be made
    all the time about ambiguous substantive laws, adopting a rule that prohibits us
    from ever upholding an officer’s entirely reasonable probabilistic judgment about
    even a painfully opaque state statute.
    - 12 -
    C
    While the court fails to offer a persuasive account of the need for its new
    rule, one might wonder whether some other, unarticulated reason exists sufficient
    to sustain its conclusion.
    One might wonder, for example, whether adopting any more forgiving an
    approach toward mistakes of law would risk inviting the moral hazard of
    discouraging officers from familiarizing themselves with the laws they are
    expected to enforce. Or whether failing to follow my colleagues’ new rule might
    even have the unintended secondary effect of inviting state legislatures to make
    their legal codes even more voluminous, knowing that by complicating the law
    they help make exclusion less likely.
    These concerns have certainly given me pause in considering this case and
    no doubt will give pause to anyone concerned with Fourth Amendment values.
    But the difficulty is we also have to worry about any legal regime that fails to
    encourage officers to investigate the facts thoroughly enough or attend to the
    Constitution’s commands carefully enough. And as we’ve seen, the Supreme
    Court has long told us that the traditional totality of the circumstances approach
    affords sufficient protection against the relevant moral hazards in these situations
    by permitting us to identify unreasonable officer mistakes of fact or constitutional
    law, hold them unlawful, and in this manner deter future similar improper
    conduct. Before abandoning that approach, we need some account why it is
    - 13 -
    uniquely ill-suited to mistakes of substantive law, why the totality of the
    circumstances approach is insufficient to address the relevant moral hazards only
    when it comes to mistakes of substantive law. That is a burden, however, neither
    Mr. Nicholson nor the court has sought to carry. 10
    Some have observed that lay persons can’t use “ignorance of the law” as an
    excuse for their torts or crimes. Given this rule, they submit, law enforcement
    officers shouldn’t be allowed to invoke the excuse to defend their searches and
    seizures. Simple fairness, the argument goes, requires no less.
    I am not immune to the tug of this idea either but unexposed difficulties
    lurk here too. Most significantly, the notion that “ignorance of the law is no
    excuse” for defendants accused of crime or sued in tort is “subject to numerous
    exceptions and qualifications.” Wayne R. LaFave, Substantive Criminal Law §
    5.6(a) (2d ed.). Some commentators have gone so far as to suggest that “[n]o area
    of the substantive criminal law has traditionally been surrounded by more
    confusion than that of ignorance or mistake of fact or law.” Id. So, for example,
    10
    The court does say “fears that [its] rule is too restrictive” are
    “overstated” because any section of the traffic code — not just the one an officer
    cites — can be used to uphold a traffic stop. Maj. Op. at 13. But I am not
    concerned with whether the court’s rule is “too restrictive” as a matter of policy,
    only with whether that new rule can be justified in light of existing jurisprudence.
    Besides, the court’s argument may prove too much. By parallel reasoning,
    shouldn’t we adopt a categorical rule holding unconstitutional stops resting on an
    officer’s reasonable mistake that facts existed to permit the seizure when, in fact,
    no such facts existed? Such a rule, one might argue, wouldn’t be “too restrictive”
    because we already allow the government to justify a stop by pointing to facts
    unknown to the arresting officer but known to other officers.
    - 14 -
    a defendant’s mistake of law does form a valid excuse if and when it negates a
    mens rea element necessary to secure liability or a conviction: a man who walks
    off with another’s umbrella on a rainy day thinking theft is not a crime may have
    no defense at common law, but the man who takes another’s umbrella thinking
    (incorrectly) his right to it has vested very well may have a good defense because
    theft often requires proof of an intent to deprive the owner the possession of his
    property. Id. Nor is that the end to the confusion. Even the apparently simple
    task of distinguishing between mistakes of fact and law can often prove vexing,
    so much so that in past cases we’ve sometimes had to remand the task to the
    district court for help. See, e.g., Tibbetts, 396 F.3d at 1138-39.
    As all this highlights, if we really wanted to take up the task of
    transmogrifying a mens rea defense from tort and crime into a new Fourth
    Amendment rule — never mind that the Fourth Amendment usually doesn’t care
    about an officer’s state of mind — it would prove a much more subtle and
    onerous task than adopting a simple rule against all officer mistakes of
    substantive law. In each case we would have to ask not only whether the officer’s
    error really qualifies as one of law rather than fact — a question that would itself
    often wind up occupying much time and effort — we would also have to ask
    whether the error bears a closer resemblance to the mistake of the man who thinks
    his right to an umbrella has vested rather than the mistake of the man who thinks
    theft isn’t a crime. At the end of the day, too, we would have to ask whether the
    - 15 -
    game is worth the candle, whether the complex regime we’ve created is actually
    any fairer or more protective of Fourth Amendment values than the traditional
    totality of the circumstances test.
    My colleagues hint at a future where these questions come very much alive.
    Anticipating what we might call the umbrella problem, they acknowledge that
    “some mistakes of law — say as to legal ownership — might nonetheless be
    excused as being closer to a mistake of fact” for Fourth Amendment purposes.
    Maj. Op. at 17. My colleagues thus adorn their new rule with a notable exception
    from its birth. And in doing so they invite debate in future cases over which
    officer errors of law are and are not close enough to factual errors to be treated as
    mistakes of fact subject to a totality of the circumstances analysis rather than
    subject to their new (now semi-)categorical rule for mistakes of law. The court’s
    candor about all this is admirable but it also suggests a future in which our
    attention is deflected from the underlying Fourth Amendment reasonableness
    question to the collateral and formalistic task of trying to distinguish “pure”
    mistakes of law from mistakes of law that seem “closer to” mistakes of fact. A
    future in which our course will be a good deal more convoluted but fail to yield
    any greater protection for Fourth Amendment values.
    Neither is this the only concern we should have about the future. To avoid
    violating the Fourth Amendment, my colleagues insist that officers have to avoid
    mistakes even very able judges make when interpreting highly reticulated and
    - 16 -
    ambiguous statutes. But what about, say, ambiguous case law? Especially when
    (as happens from time to time despite everyone’s best intentions) the relevant
    case law is demonstrably inconsistent? What about obscure regulatory edicts that
    may bear on an officer’s work? What about an officer charged with local
    ordinance that turns out to offend state statutes and is therefore invalid? See, e.g.,
    United States v. Alexander, No. 07-00256, 
    2008 WL 2714076
    , at *10-11 (M.D.
    Tenn. July 9, 2008); Combined Commc’ns Corp. v. City & Cnty. of Denver, 
    542 P.2d 79
    , 82-83 (Colo. 1975). In an age where law is as plentiful as trees in a
    forest and as tangled as the undergrowth, is it really appropriate to assume — as
    the court does — that every mistake of law is a Fourth Amendment violation?
    Perhaps to avoid these complications there will emerge some way to limit
    the court’s holding today to officer errors of statutory law. But doing so would
    itself only raise further questions about the value and appropriateness of the
    court’s new rule in the first place. Consider the court’s effort to distinguish the
    local ordinance problem I’ve identified. The court says an officer “likely” would
    be justified in relying on and enforcing the ordinance “based on the reliance
    principles set forth in the Supreme Court’s cases analyzing mistakes regarding the
    constitutionality of the law.” Maj. Op. at 17. But any resolution of a conflict
    between a local ordinance and state law is itself a question purely of state law (if
    sometimes state constitutional law), and the Supreme Court’s existing cases
    excusing reasonable mistakes of constitutional law are restricted to mistakes of
    - 17 -
    federal constitutional law. So it seems the court today is prepared to open a
    second exception to its new rule about officer mistakes of law, one for errors
    concerning conflicts between local and state law. These errors may be treated
    under the usual totality of the circumstances test while errors in questions of pure
    statutory interpretation must be held, categorically, to violate the Fourth
    Amendment. In suggesting as much, the court only speeds us further down the
    road toward a regime with a “rule” pocketed with exceptions, one that promises to
    be a good deal more complicated to administer and not obviously any more
    protective of Fourth Amendment values than simply following the usual totality
    of the circumstances approach in every case. 11
    D
    Whatever else might be said about the merits of its (now twice excepted)
    rule, the court today says its course is compelled by circuit precedent. But as it
    happens, the court today goes much further than any of our precedents — and in
    doing so propels us into the middle of a circuit split.
    11
    The court suggests that, when in doubt about the meaning of a law,
    officers “can, in some circumstances, seek a warrant to confirm their belief about
    the interpretation of a statute.” Maj. Op. at 14. But the warrant requirement
    doesn’t apply to traffic stops like the one at issue here, United States v. Arvizu,
    
    534 U.S. 266
    , 273 (2002), because officers aren’t reasonably expected to seek
    warrants from courts (let alone ones that amount to a declaratory judgment on the
    meaning of an ambiguous statute and may require a good deal of study to decide)
    while following a suspect’s car and contemplating a traffic stop.
    - 18 -
    The court says United States v. DeGasso, 
    369 F.3d 1139
     (10th Cir. 2004),
    obliges it to hold all officer mistakes of law offend the Fourth Amendment. But
    that case merely ruled that an officer’s “failure to understand the plain and
    unambiguous law he is charged with enforcing . . . is not objectively reasonable.”
    Id. at 1144-45 (emphasis added). In that case, too, there was no other evidence
    bearing on the officer’s reasonableness or unreasonableness before the court.
    Absent any attenuating circumstances, I don’t doubt we’d all agree without a
    moment’s pause that an officer’s failure to follow “plain and unambiguous” laws
    is unreasonable. But whether that description fairly applies to our case no one
    can say at this point. The district court has yet to assess the circumstances
    surrounding Officer Baker’s stop. And the court itself today expressly assumes
    the statute before us is ambiguous and so, by definition, seemingly untouched by
    DeGasso’s holding concerning officer mistakes about the meaning of “plain and
    ambiguous” statutes. Maj. Op. at 9.
    The court also points to a sentence in Tibbetts stating that the “failure to
    understand the law by the very person charged with enforcing it is not objectively
    reasonable.” 396 F.3d at 1138 (emphasis in original). This language, the court
    reasons, requires us to hold that even an officer’s mistake about the most
    perplexingly ambiguous law is never reasonable for Fourth Amendment purposes.
    The difficulty is, the Tibbetts court wasn’t even sure whether the mistake at issue
    before it was one of fact or law and remanded the case to the district court to
    - 19 -
    make that call, a call that could have easily wound up with a determination the
    error wasn’t one of law in the first place. Id. at 1138-39. It isn’t clear, then,
    whether Tibbetts’s stray sentence about mistakes of law that my colleagues lean
    on so heavily was even necessary to the resolution of the case or just dicta. See
    NLRB v. Int’l Bhd. of Elec. Workers, Local 340, 
    481 U.S. 573
    , 591 n.15 (1987)
    (statements “unnecessary to the disposition ” are “dict[a]” ). The same sort of
    difficulty attends the court’s reliance on Sherouse v. Ratchner, 
    573 F.3d 1055
    (10th Cir. 2009), where the court held the mistake before it wasn’t one of law at
    all but one better characterized as one of fact. Id. at 1060.
    Neither, for that matter, is there any evidence that the court and parties in
    Tibbetts or Sherouse grappled with the reasonableness or unreasonableness of
    officer mistakes about ambiguous laws. Certainly neither case mentions the issue
    or the competing arguments on both sides of that debate — let alone
    acknowledges the circuit split we shall witness in a moment. And it is well
    settled that “[q]uestions which merely lurk in the record, neither brought to the
    attention of the court nor ruled upon, are not to be considered as having been so
    decided as to constitute precedents.” See Cooper Indus., Inc. v. Aviall Servs.,
    Inc., 
    543 U.S. 157
    , 170 (2004) (quoting Webster v. Fall, 
    266 U.S. 507
    , 511
    (1925)).
    While this circuit has never before ventured a holding so bold as my
    colleagues do today, I readily acknowledge some others have adopted the
    - 20 -
    categorical, no-mistakes-of-substantive-law rule my colleagues now endorse. See ,
    e.g., United States v. McDonald, 
    453 F.3d 958
    , 961 (7th Cir. 2006); United States
    v. Chanthasouxat, 
    342 F.3d 1271
    , 1279 (11th Cir. 2003); United States v. Lopez-
    Soto, 
    205 F.3d 1101
    , 1106 (9th Cir. 2000); United States v. Miller, 
    146 F.3d 274
    ,
    279 (5th Cir. 1998). But many of these decisions seem to rely on the problematic
    analogy to the common law’s dictum that ignorance-of-the-law-is-no-excuse. And
    many other courts besides have expressly rejected such a categorical approach,
    preferring instead the traditional totality of the circumstances test. See, e.g.,
    United States v. Martin, 
    411 F.3d 998
    , 1001 (8th Cir. 2005); Travis v. State, 
    959 S.W.2d 32
    , 34 (Ark. 1998); Moore v. State, 
    986 So. 2d 928
    , 935 (Miss. 2008);
    State v. Heien, 
    737 S.E.2d 351
    , 356 (N.C. 2012); City of Wilmington v. Conner,
    
    761 N.E.2d 663
    , 667 (Ohio Ct. App. 2001); State v. Wright, 
    791 N.W.2d 791
    , 799
    (S.D. 2010).
    Given how divided courts are, perhaps neither my colleagues nor I can
    claim the trump card when it comes to citing precedent and the only thing we can
    know for certain is that the substantive Fourth Amendment question dividing us
    will remain unsettled until our superiors speak.
    III
    A
    Even when a Fourth Amendment violation exists, exclusion of evidence
    does not automatically follow. Other remedies (from administrative to civil) exist
    - 21 -
    to punish and deter officer misconduct. To be sure, exclusion is an especially
    potent remedy, but it is one courts may choose to apply or not apply as a
    “prudential” matter, not one individuals may insist on as a matter of “personal
    constitutional right.” Davis v. United States, 
    131 S. Ct. 2419
    , 2426 (2011)
    (internal quotation marks omitted); see also Herring v. United States, 
    555 U.S. 135
    , 141 (2009).
    Whether suppression is the right remedy in any particular case requires, the
    Supreme Court has said, an assessment of the competing social costs and benefits
    associated with exclusion. See Davis, 131 S. Ct. at 2427 (“Real deterrent value is
    a necessary condition for exclusion, but it is not a sufficient one. The analysis
    must also account for the substantial social costs generated by” exclusion
    (citations and internal quotation marks omitted)); Herring, 555 U.S. at 141.
    Trying to administer this cost-benefit task is difficult under the best of
    circumstances. In deciding whether to impose exclusion, courts must “weigh” or
    “compare” incommensurate goods (the deterrence benefits associated with
    suppression) and costs (the losses to society as a result of allowing criminal
    conduct to go unpunished) — a challenge akin to “comparing constitutional apples
    with constitutional oranges.” Orin S. Kerr, Good Faith, New Law, and the Scope
    of the Exclusionary Rule, 99 Geo. L.J. 1077, 1108 (2011); see also Joseph Raz,
    The Morality of Freedom ch.13 (1986). A challenge made all the more complex
    by the grand societal scale on which the measurement is supposed to take place.
    - 22 -
    Trying to administer the cost-benefit analysis without the benefit of the
    district court’s factual findings on the relevant questions makes a tough task
    tougher still. At this point, for example, we don’t have any factual findings about
    how deterrable Officer Baker’s mistake might have been — findings that might
    allow us to judge how beneficent exclusion might prove to be. We don’t know if
    the officer stopped Mr. Nicholson because he lazily assumed the law must
    preclude the maneuver, because he diligently studied what was (incorrectly) taught
    at the police academy, or because he took his own best shot at reading the left-turn
    statute. Because we don’t know the relevant facts, we can’t meaningfully assess
    the risk that failing to exclude here would encourage other officer mistakes of law
    — the likelihood that failing to exclude, in other words, would invite moral
    hazard. Neither do we have a full picture of the social costs that might or might
    not be associated with exclusion in this case. As I have already explained, I would
    remand the substantive Fourth Amendment question. Given that, it seems to me
    there is no reason to try to tackle the remedial question and its attendant factual
    questions for the first time in an appellate vacuum. After considering on remand
    whether Officer Baker’s conduct was constitutionally unreasonable, I would
    simply ask the district court to proceed to the question whether, assuming a
    constitutional violation, exclusion is the appropriate remedy.
    Appearing to recognize the challenges associated with its cost-benefit
    approach, the Supreme Court has recently offered an alternative and seemingly
    - 23 -
    more tractable test. It has instructed that the “basic insight” guiding the remedial
    inquiry is that “the deterrence benefits of exclusion vary with the culpability of the
    law enforcement conduct at issue. When the police exhibit deliberate, reckless, or
    grossly negligent disregard for Fourth Amendment rights, the deterrent value of
    exclusion is strong and tends to outweigh the resulting costs.” Davis, 131 S. Ct. at
    2427 (alteration omitted) (citations omitted) (internal quotation marks omitted).
    The deterrent benefits associated with exclusion outweigh the costs, too, when law
    enforcement exhibits “recurring or systemic negligence.” Id. at 2428. But when
    officers behave only non-negligently “or when their conduct involves only simple,
    isolated negligence, the deterrence rationale loses much of its force.” Id. at 2427-
    28 (citations omitted) (internal quotation marks omitted). In these cases,
    exclusion’s “costly toll upon truth-seeking and law enforcement objectives” prove
    insufficient to “pay its way.” Herring, 555 U.S. at 141, 147-48.
    This new culpability framework sounds familiar, even comforting, to
    judicial ears: courts are often called on to assess questions of culpability and they
    arguably bear more comparative advantages for that task than for performing
    society-wide cost-benefit analyses. Even so, it still seems to me the best place to
    begin the work of applying this framework lies in the district court — not this one.
    So I would ask the district court on remand to consider not just cost-benefit
    questions but culpability questions too. At this stage, this court simply doesn’t
    have enough facts to venture a guess what answers the culpability test might yield
    - 24 -
    in this particular case. Based on what we do know, it seems evident Officer
    Baker’s conduct didn’t evince any deliberate or reckless indifference to Mr.
    Nicholson’s rights. Less clear, though, is whether the officer’s conduct was
    grossly negligent, simply negligent, or not negligent at all. Evidence would help
    sort this out.
    Now, I admit some unanswered legal questions also exist about the
    culpability framework and a district court trying to handle this case on remand
    would reasonably expect our guidance on them in advance. What, for example,
    does the Supreme Court have in mind when it speaks of “simple, isolated”
    negligence? The phrase might mean “simple” (or ordinary) negligence that
    doesn’t occur very often (and so in this sense is “isolated”). Alternatively, the
    phrase might mean ordinary negligence committed by a third party who is in that
    sense “isolated” from the arresting officer. It seems to me the first alternative is
    by far the more likely. The first interpretation comports with the use of the term
    “isolated” in Herring, where the Court separately used the term “attenuation” —
    not “isolated” — to refer to a third party actor who committed the error. See 555
    U.S. at 150 (referring to “an isolated, negligent recordkeeping error attenuated
    from the arrest”). And the second alternative leaves us with an
    underdeterminative scheme, one lacking any guidance on how to treat ordinary
    negligence by arresting officers — a most unlikely outcome.
    - 25 -
    The line between “simple” and “gross” raises questions too. When it comes
    to defining degrees of negligence, adjectival epithets like “gross,” “wanton,” and
    “wicked” have long proven frustratingly protean. See, e.g., Steamboat New World
    v. King, 
    57 U.S. 469
    , 474 (1853); Daniels v. Williams, 
    474 U.S. 327
    , 334 (1986);
    Wilson v. Brett, (1843) 152 Eng. Rep. 737 (Exch. of Pleas) 739; 11 M. & W. 113,
    115-16. Suggestively, though, Davis and Herring refer to recklessness and gross
    negligence as separate categories and presumably this much indicates the Court
    intends a difference. We know that recklessness usually requires proof of a
    conscious indifference to the consequences of one’s conduct. See Model Penal
    Code § 2.02; W. Page Keeton et al., Prosser and Keeton on the Law of Torts § 34,
    at 211-12 (5th ed. 1984). So it seems we could safely advise the district court that
    gross negligence in this context requires a degree of officer culpability more than
    standard unreasonable conduct (negligence) but less than a conscious indifference
    to the consequences of his conduct (recklessness). 12
    12
    Determining what separates “isolated” from “recurring” negligence
    presents difficulties as well. Should we look at the particular police department,
    the county, the state, or entire country? And what should we do about mistakes
    that appear more reasonable the more they occur? See, e.g., Chanthasouxat, 342
    F.3d at 1279 (officer mistake of law “reasonable” when officer had “history of
    having written more than 100 tickets” in similar circumstances). And might the
    possibility that a failure to exclude would invite recurring negligence — the
    moral hazard problem and a possibility in this case — suffice for a finding of
    recurring negligence? On all this, we have no guidance from the Supreme Court
    yet and I confess I am without any advice to offer the district court. Some
    questions, and these may be among them, just have to be sorted out in cases as
    they come.
    - 26 -
    B
    My colleagues bypass the hard remedial questions, factual and legal. After
    finding a Fourth Amendment violation, they proceed immediately to order
    exclusion of evidence and instruct the district court to vacate Mr. Nicholson’s
    drug and firearm convictions. They say we can and should disregard the various
    remedial inquiries the Supreme Court has dictated because the government didn’t
    argue the question of remedy in the district court and thus forfeited it on appeal.
    See Maj. Op. at 20.
    I do not believe this is a course open to us. It is long settled that an
    appellee is entitled to “defend the judgment [it] won below on any ground
    supported by the record.” Robinson v. Robinson (In re Robinson), 
    921 F.2d 252
    ,
    253 (10th Cir. 1990); see also S. Utah Wilderness Alliance v. Bureau of Land
    Mgmt., 
    425 F.3d 735
    , 745 n. 2 (10th Cir. 2005); Tinkler v. United States ex rel.
    FAA, 
    982 F.2d 1456
    , 1461 n. 4 (10th Cir.1992). It is settled, too, that “in
    reviewing the decision of a lower court, it must be affirmed if the result is correct
    although the lower court relied upon a wrong ground or gave a wrong reason.”
    S.E.C. v. Chenery Corp., 
    318 U.S. 80
    , 88 (1943) (quotation marks omitted);
    Helvering v. Gowran, 
    302 U.S. 238
    , 245 (1937) (collecting authority). While the
    government didn’t present a remedial argument in the district court, it prevailed on
    the substantive Fourth Amendment question and so had little need to proceed to
    the question of remedy. Now defending its victory on appeal, the government has
    - 27 -
    expressly argued — as it is entitled to do — that the district court should be
    affirmed either because no substantive Fourth Amendment violation occurred as
    the district court reasoned or because, even if a violation did occur, suppression is
    an inappropriate remedy. Mr. Nicholson has responded to both lines of defense.
    The remedial issue is thus properly presented and developed as an alternative
    ground for affirmance. I do not see how we might simply ignore the argument.
    To this, the court replies by offering a second, separate rationale for
    declining to consider the remedial question. It contends that even if we took up
    the question the record as currently constituted is insufficient to permit us to
    affirm. Maj. Op. at 20. This course at least has the virtue of confronting the
    appellee’s alternative argument for affirmance, as we are obliged to do. But if, as
    I have suggested, a remand is already required on the substantive Fourth
    Amendment question, it follows that we should also permit the district court to
    develop a record and assess the remedial question on remand as well. Especially
    when the Supreme Court has instructed us — repeatedly — that exclusion isn’t
    automatic but should be closer to a “last resort’” than a “first impulse.” Hudson,
    547 U.S. at 591; see also Davis, 131 S. Ct. at 2426; Herring, 555 U.S. at 141. In
    similar circumstances other circuits have routinely followed exactly the path I
    suggest. See, e.g., United States v. Fugate, 499 F. App’x 514, 520 (6th Cir. 2012)
    (unpublished); United States v. Wright, 493 F. App’x 265, 273 (3d Cir. 2012)
    - 28 -
    (unpublished); United States v. Master, 
    614 F.3d 236
    , 243 (6th Cir. 2010); United
    States v. Julius, 
    610 F.3d 60
    , 67-68 (2d Cir. 2010).
    ***
    With a healthy dose of hindsight we know Officer Baker, like the district
    court, made a mistake. In my view, it’s enough work for the day to correct the
    mistake and remand the case for a thorough reassessment in that new light. My
    colleagues prefer a more arduous journey — to a new categorical rule, then to
    exceptions to that categorical rule, and finally to a refusal to entertain the
    government’s remedial argument. I do not doubt their journey is grounded in a
    wish to give voice to the Fourth Amendment. But at the end of the day I am
    unable to join them because the trip seems to me both unnecessary to resolve this
    appeal, uncertain to yield any benefit for Fourth Amendment values, and destined
    to take us places inconsistent with the Supreme Court’s instructions and into
    circuit splits besides. I respectfully dissent.
    - 29 -