United States v. Cox , 906 F.3d 1170 ( 2018 )


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  •                                                                        FILED
    United States Court of Appeals
    PUBLISH                          Tenth Circuit
    UNITED STATES COURT OF APPEALS                October 16, 2018
    Elisabeth A. Shumaker
    FOR THE TENTH CIRCUIT                   Clerk of Court
    _________________________________
    UNITED STATES OF AMERICA,
    Plaintiff - Appellee,
    v.                                                  No. 17-3034
    SHANE COX,
    Defendant - Appellant.
    ____________________
    STATE OF KANSAS,
    Intervenor - Appellant.
    –––––––––––––––––––––––––––––––––––
    UNITED STATES OF AMERICA,
    Plaintiff - Appellee,
    v.                                                  No. 17-3035
    JEREMY KETTLER,
    Defendant - Appellant.
    ____________________
    STATE OF KANSAS,
    Intervenor - Appellant.
    _________________________________
    Appeal from the United States District Court
    for the District of Kansas
    (D.C. No. 6:15-CR-10150-JTM)
    _________________________________
    Paige A. Nichols, Assistant Federal Public Defender (Melody Brannon, Federal Public
    Defender, with her on the briefs), Topeka, Kansas, for Defendant–Appellant Shane Cox.
    Joseph W. Miller of Law Offices of Joseph Miller, LLC, Fairbanks, Alaska (Robert J.
    Olson, William J. Olson, Jeremiah L. Morgan, Herbert W. Titus of William J. Olson,
    P.C., Vienna, Virginia, with him on the briefs) for Defendant–Appellant Jeremy Kettler.
    Derek Schmidt, Attorney General of Kansas, Jeffrey A. Chanay, Chief Deputy Attorney
    General, Toby Crouse, Solicitor General of Kansas, Dwight R. Carswell and Bryan C.
    Clark, Assistant Solicitors General, Topeka, Kansas, for Intervenor–Appellant.
    Elizabeth H. Danello, Attorney, Appellate Section, Criminal Division, Department of
    Justice, Washington, D.C. (Stephen R. McAllister, United States Attorney, District of
    Kansas, Jared S. Maag, Assistant United States Attorney, District of Kansas, Kenneth A.
    Blanco, Acting Assistant Attorney General, and Trevor N. McFadden, Deputy Assistant
    Attorney General, Department of Justice, Washington, D.C., with her on the brief) for
    Plaintiff–Appellee.
    _________________________________
    Before HARTZ, SEYMOUR, and PHILLIPS, Circuit Judges.
    _________________________________
    PHILLIPS, Circuit Judge.
    _________________________________
    This is a tale of two laws: the National Firearms Act (NFA), 26 U.S.C.
    §§ 5801–5872, which requires the registration of statutorily defined firearms, and
    Kansas’s Second Amendment Protection Act (SAPA), ch. 100, 2013 Kan. Sess. Laws
    vol. 1 500–03 (codified at Kan. Stat. Ann. §§ 50-1201 to -1211 (2014)), which
    purports to exempt any personal firearm, firearm accessory, or ammunition
    manufactured, owned, and remaining within Kansas’s borders from “any federal
    law, . . . including any federal firearm or ammunition registration program, under the
    2
    authority of congress to regulate interstate commerce.” Kan. Stat. Ann. § 50-1204(a).
    In 2014, these two laws intersected when the government prosecuted two Kansas
    men, Shane Cox and Jeremy Kettler, for violating the NFA by manufacturing (in
    Kansas), transferring (in Kansas), and possessing (in Kansas) several unregistered
    firearms. A jury found them guilty of most (though not all) of the charges.
    Now, Cox and Kettler appeal their convictions, though they don’t dispute that
    their actions ran afoul of the NFA.1 First, they challenge the NFA’s constitutionality,
    alleging that the statute is an invalid exercise of congressional power and an invasion
    of the Second Amendment right to bear arms. Second, they challenge the district
    court’s ruling that their reliance on the SAPA, which they understood to shield
    Kansas-made and -owned firearms from federal regulation, provided no defense to
    charges that they violated the NFA. Kettler further asks us to see his prosecution as
    the product of a dispute between Kansas and the federal government over the SAPA,
    a dispute that unjustly swept him up (along with Cox, though Cox hasn’t joined this
    argument). We also granted Kansas’s request to participate in these appeals as needed
    to defend the SAPA from a Supremacy Clause challenge.
    1
    Cox and Kettler each appealed individually (in cases nos. 17-3034 and
    17-3035, respectively), but because their appeals raise overlapping issues, we granted
    the government leave to file a single response brief. We consider Cox’s and Kettler’s
    appeals companioned cases (though we never formally consolidated them), separately
    submitted to the same panel for oral argument and decision.
    3
    We reject Cox’s and Kettler’s challenges to their convictions (without
    addressing the SAPA’s constitutionality). Exercising jurisdiction under 28 U.S.C.
    § 1291, we therefore affirm the district court’s judgments.
    BACKGROUND
    In 2014, Shane Cox ran Tough Guys, an army-surplus store in Chanute,
    Kansas. Inside the store, near a glass display case filled with homemade silencers,
    Cox had posted a copy of the SAPA (which the Kansas legislature passed a year
    earlier) for his customers to read. See Kan. Stat. Ann. §§ 50-1201 to -1211. Drawing
    on the Second, Ninth, and Tenth Amendments to the U.S. Constitution, as well as the
    Kansas Constitution’s bill of rights, the SAPA purports to protect from federal
    interference the availability of all firearms, firearm accessories (including silencers2),
    and ammunition made, sold, and kept “within the borders of Kansas.” Kan. Stat. Ann.
    §§ 50-1202, 50-1203(b), 50-1204(a), 50-1206 to -1208; see also Kan. Const. Bill of
    Rights § 4 (guaranteeing an individual right to bear arms).
    The display caught the attention of Jeremy Kettler, an army veteran from
    neighboring Humboldt who’d walked into Tough Guys to look around. Cox was in
    2
    The Kansas law uses the term “sound suppressors” instead of “silencers.”
    See, e.g., Kan. Stat. Ann. § 50-1203(b). Kettler, too, prefers “suppressor” to “the
    more colloquial term ‘silencer,’” explaining that “while such a device will ‘suppress’
    the noise of a gunshot to below a level that would cause hearing damage,” it
    “come[s] nowhere close to ‘silencing’ the sound of a gunshot, as is depicted in
    television and movies.” Kettler’s Opening Br. at 10 n.5. But the NFA uses “silencer,”
    as does Cox. 26 U.S.C. § 5845(a)(7); see also, e.g., Cox’s Opening Br. at 2. So for
    consistency’s sake (and without expressing an opinion on either term’s accuracy), we
    adopt “silencer” throughout this opinion.
    4
    the store, so Kettler asked him about the law and the silencers. Neither Cox nor
    Tough Guys held a federal firearms license, but Cox believed that as a result of the
    SAPA, he could avoid the “red tape” of federal firearms regulations as long as the
    silencers never left Kansas. Cox R. vol. 3 at 292:9–11. Kettler bought one of Cox’s
    silencers and later praised it (and Tough Guys) in a Facebook post.
    In December 2014, the Bureau of Alcohol, Tobacco, Firearms and Explosives
    (ATF) learned that Tough Guys was selling unregistered silencers and started an
    investigation. Within a year, federal prosecutors secured a grand jury indictment
    against Cox and Kettler, charging them with thirteen crimes linked to Cox’s firearms-
    manufacturing venture, Kettler’s patronage of it, and the ensuing investigation. Count
    1 alleged that Kettler had knowingly and willfully made false statements “[d]uring a
    [f]ederal [i]nvestigation,” in violation of 18 U.S.C. § 1001. Cox R. vol. 1 at 28.
    Counts 2, 3, and 4 each charged Cox with possessing an unregistered firearm—a
    destructive device, a short-barreled rifle, and another destructive device,3
    respectively—in violation of 26 U.S.C. § 5861(d). Count 5 accused both Cox and
    Kettler of conspiring, under 18 U.S.C. § 371, to violate the NFA by building and
    selling an unregistered silencer. Counts 6, 7, 8, 9, and 11 charged Cox with five
    violations of 26 U.S.C. § 5861(e) for transferring five silencers—four to recipients
    3
    The NFA defines a destructive device as “any explosive, incendiary, or
    poison” gas, bomb, grenade, rocket, mine, or similar device, as well as “any
    combination of parts either designed or intended” to be converted into such a device.
    26 U.S.C. § 5845(f). Prosecutors alleged that Cox had kept some “grenade husks,”
    accelerant, and other components in his workshop. Cox R. vol. 3 at 221:14.
    5
    identified by their initials plus a fifth to “an undercover law enforcement officer.”
    Cox R. vol. 1 at 34. Count 10 accused Cox of making a silencer in violation of 26
    U.S.C. § 5861(f). Count 12 alleged that between June 20, 2014, and February 4,
    2015, Cox had “engaged in the business of manufacturing and dealing in” silencers in
    violation of 26 U.S.C. § 5861(a). Cox R. vol. 1 at 34. And count 13 charged Kettler
    with possessing a silencer in violation of 26 U.S.C. § 5861(d).
    Cox and Kettler each pleaded not guilty and moved to dismiss the NFA-based
    charges,4 claiming—for slightly different reasons—that the SAPA shielded them
    from criminal liability for running afoul of federal firearms regulations.5 Cox argued
    that because of the SAPA, enforcing the NFA against him would exceed the federal
    government’s constitutional authority and usurp “powers reserved to the States” in
    violation of the Tenth Amendment. Cox R. vol. 1 at 39. Kettler, in turn, asserted
    entrapment by estoppel. By enacting the SAPA, argued Kettler, the Kansas
    legislature had “specifically” told him that federal laws didn’t apply to his Kansas-
    made and -owned suppressor, and his reasonable reliance on Kansas’s promise
    rendered the federal prosecution unjust. 
    Id. at 69.
    The district court rejected both arguments in one written order. See United
    States v. Cox (Cox I), 
    187 F. Supp. 3d 1282
    , 1285–88 (D. Kan. 2016). First it ruled,
    4
    Kettler didn’t contest count 1, the false-statement charge.
    5
    Cox and Kettler also each moved “to join in any and all motions and
    memoranda” filed by the other. Cox R. vol. 1 at 62; Kettler R. vol. 1 at 65. The
    district court granted their motions.
    6
    based on Supreme Court and circuit precedent, that the NFA was a valid exercise of
    Congress’s taxing power. 
    Id. at 1285–87.
    Next the court threw out Kettler’s
    entrapment-by-estoppel defense, reasoning that because state officials lack the power
    to construe or enforce federal law, it wasn’t reasonable for Kettler to rely on the
    Kansas legislature’s representations about the reach of federal law. 
    Id. at 1287–88.
    The court therefore denied the motions to dismiss the indictment. 
    Id. at 1288.
    A few months later, the government submitted a pre-trial motion asking the
    court to “find that any defense based on Kansas’ enactment of the [SAPA] is not a
    valid legal defense.” Cox R. vol. 1 at 106. And to keep the Kansas statute from
    confusing matters for the jury, the government sought “a prohibition on any mention”
    of the SAPA. 
    Id. vol. 3
    at 16:21–22. The court initially granted the government’s
    request, but then tempered that ruling in response to Kettler’s offer of proof, which
    convinced the court that “references to [the] SAPA [we]re interwoven with the
    evidence of the alleged offenses.”6 
    Id. vol. 1
    at 194. The court maintained that the
    SAPA “provide[d] no defense” to the charged offenses, 
    id. at 193,
    but it declined to
    “excise” the SAPA from the evidence and predicted that some mention of the law
    would be admissible to contextualize the charged offenses, 
    id. at 194.
    And if (as the
    6
    Kettler’s proffer of SAPA-related evidence included: (1) that Cox handed out
    copies of the SAPA to customers, including Kettler, who bought silencers; (2) that
    Kettler knew about the SAPA and relied on it; (3) that an ATF agent who’d talked to
    Kettler on the phone learned that Kettler “was confused as to the investigation into
    Cox and his silencers because of the existence of the State law”; and (4) that Cox had
    informed Kettler of the SAPA when the two discussed silencers. Cox R. vol. 1 at 133.
    7
    court assumed) the SAPA surfaced at trial, the court promised to instruct jurors on
    how to consider the law.
    The state of Kansas, meanwhile, moved to intervene. Federal law gives a state
    the right to intervene “[i]n any action, suit, or proceeding in a court of the United
    States . . . wherein the constitutionality of any statute of that State affecting the
    public interest is drawn in question.” 28 U.S.C. § 2403(b). So far in this case, the
    district court had neither ruled nor been asked to rule on the SAPA’s
    constitutionality. Yet considering the breadth of the words “drawn into question,” the
    court decided to grant Kansas’s motion to intervene. Cox R. vol. 1 at 197 (quoting 28
    U.S.C. § 2403(b)). Kansas couldn’t present evidence or directly participate in the
    trial, but the court’s order allowed the state “to be heard on any subsequent rulings
    that implicate[d] the constitutionality of [the] SAPA.” 
    Id. The cases
    proceeded to a joint trial in November 2016. After Cox rested on the
    third day, and again after Kettler rested on the fourth, both moved for judgments of
    acquittal. The court ultimately dismissed the conspiracy charge against both
    defendants, having seen “no evidence . . . of a conspiracy between Mr. Cox and
    Mr. Kettler,” and the false-statement charge against Kettler. Cox R. vol. 3 at 565. Yet
    it found that the government had presented sufficient evidence to send the remaining
    counts to the jury.
    The jury began deliberating on the fourth day, and it returned a verdict later
    the same day, finding Cox not guilty of the destructive-device-possession counts (2
    and 4) but guilty of the remaining eight counts: unlawfully possessing a short-
    8
    barreled rifle in count 3; unlawfully transferring silencers in counts 6, 7, 8, 9, and 11;
    unlawfully making a silencer in count 10; and unlawfully engaging in business as a
    dealer or manufacturer of silencers in count 12. The jury also found Kettler guilty of
    the remaining count against him, unlawfully possessing a silencer in count 13.
    The day before the court submitted the case to the jury, Kettler (joined by Cox)
    filed a motion “to dismiss the present prosecution.” Cox R. vol. 1 at 218. They
    argued that because the NFA provisions at issue—26 U.S.C. §§ 5861 and 5871,
    which lay out prohibitions and penalties—had “become merely regulatory
    punishment,” the provisions exceeded Congress’s power to tax and, in fact, usurped
    power that the Tenth Amendment reserved to the states. 
    Id. at 220.
    The motion
    doesn’t mention the Second Amendment, but after Kansas submitted a response
    defending the SAPA on Second Amendment grounds, Kettler filed a reply relying
    almost exclusively on that amendment and urging the court to find that the NFA
    unconstitutionally infringed the right to bear arms.
    The district court addressed both arguments in a January 2017 written order.
    United States v. Cox (Cox II), 
    235 F. Supp. 3d 1221
    , 1222–23 (D. Kan. 2017). The
    court reiterated its conclusion, based on Supreme Court precedent, that the NFA is a
    valid exercise of Congress’s taxing power. 
    Id. at 1225;
    accord Cox 
    I, 187 F. Supp. 3d at 1285
    , 1287. And “if the NFA is otherwise consistent with the Constitution and
    constitutes a valid exercise of Congress’s taxing power,” the court reasoned, “then it
    does not run afoul of the Tenth Amendment.” Cox 
    II, 235 F. Supp. 3d at 1225
    . Next,
    the court concluded that none of the NFA provisions that applied to Cox and Kettler
    9
    infringed their Second Amendment rights. 
    Id. at 1227–28.
    The court therefore denied
    the motion to dismiss. 
    Id. at 1229.
    The following month, the district court held a sentencing hearing. At that
    hearing, the court took into account Cox’s and Kettler’s reliance on the SAPA and
    gave them the benefit of that reliance. In lieu of prison time, the court sentenced Cox
    to two years’ probation and Kettler to one year’s.
    Cox and Kettler appealed their convictions, and Kansas “move[d] to
    participate as a party” in Cox’s appeal, citing 28 U.S.C. § 2403(b) and
    Fed. R. App. P. 44(b). State of Kan.’s Mot. to Participate as Party at 1–2, United
    States v. Cox, No. 17-3034 (10th Cir. May 9, 2017). The SAPA “ha[d] played a
    prominent role in [Cox’s] case,” Kansas noted, and the federal government had
    “argued at every turn that the [SAPA] is ‘clearly preempted by federal law’ and
    ‘invalid.’” 
    Id. at 2
    (quoting Cox R. vol. 1 at 87, 108). Kansas therefore asked to
    submit briefs, on the same schedule as Cox, defending the SAPA’s constitutionality.
    No one opposed the motion, so we granted it, and Kansas filed two briefs.
    DISCUSSION
    Though Cox and Kettler challenge their convictions, neither denies that he
    failed to abide by the NFA’s rules: Kettler possessed an unregistered silencer; Cox
    possessed an unregistered short-barreled rifle and dealt in unregistered silencers.
    They strike instead at the NFA itself, arguing that the Act exceeds the constitutional
    bounds of Congress’s power and violates their Second Amendment rights. In the
    alternative, even if the NFA passes constitutional muster, they contend that their
    10
    reliance on the SAPA mitigates their culpability for violating the NFA—a defense
    that, they claim, the district court erroneously kept from the jury.7 We address the
    NFA’s constitutionality first; then we turn to the SAPA and how (if at all) it affected
    Cox’s and Kettler’s culpability.
    A. The Constitutionality of the National Firearms Act
    Cox and Kettler claim that the NFA—at least as applied to their conduct8—
    suffers two constitutional infirmities, both fatal. We review each challenge de novo.
    7
    Kansas, in turn, briefed these issues:
    1. Does the National Firearms Act, specifically 26 U.S.C. § 5861,
    preempt the Second Amendment Protection Act?
    2. Did the District Court err in holding that the Second Amendment does
    not protect possession of silencers?
    Br. of Intervenor State of Kan. at 1 (Br. of Kan.). As for the first issue, though,
    preemption isn’t relevant here, and we needn’t address the SAPA’s constitutionality.
    And as for the second issue, it’s not clear how the Second Amendment’s protection
    of silencers would advance the SAPA’s constitutionality. As a result, we don’t
    directly engage any of Kansas’s arguments.
    8
    Kettler isn’t clear about whether he’s mounting a facial or an as-applied
    challenge to the NFA, while Cox specifically claims that the NFA “as applied”
    exceeds Congress’s powers and violates the Second Amendment. Cox’s Opening Br.
    at 36, 52. It’s harder to prevail on a facial challenge—unlike an as-applied challenge,
    a facial challenge fails if “at least some” constitutional applications of the challenged
    statute exist. Wash. State Grange v. Wash. State Republican Party, 
    552 U.S. 442
    , 457
    (2008) (quoting Schall v. Martin, 
    467 U.S. 253
    , 264 (1984)). And Kettler focuses on
    the NFA’s transfer provisions, such as 26 U.S.C. § 5811, rather than take on the
    statute as a whole. So, in the absence of an indication that we should do otherwise,
    we treat both Cox’s and Kettler’s constitutional challenges as challenges to the NFA
    as it applied to them. (We also note that the failure of an as-applied challenge shows
    that the statute has “at least some” constitutional applications, spelling the end of any
    facial challenge.)
    11
    United States v. Reese, 
    627 F.3d 792
    , 799 (10th Cir. 2010) (quoting United States v.
    Dorris, 
    236 F.3d 582
    , 584 (10th Cir. 2000)).
    1. Is the National Firearms Act a Valid Exercise of Congressional Power?
    Cox and Kettler argue that the NFA exceeds Congress’s power. We agree with
    the government, though: the NFA is a valid exercise of Congress’s taxing power, as
    well as its authority to enact any laws “necessary and proper” to carry out that power.
    U.S. Const. art. I, § 8, cls. 1, 18.
    Among other enumerated powers, Article I of the Constitution gives Congress
    the “Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts
    and provide for the common Defence and general Welfare of the United States,” 
    id. cl. 1,
    and “To make all Laws which shall be necessary and proper for carrying into
    Execution the foregoing Power[],” 
    id. cl. 18.
    And on its face, the NFA is a taxing scheme. The statute collects occupational
    and excise taxes from businesses and transactions involving listed firearms—which
    include short-barreled rifles, silencers, and destructive devices. See 26 U.S.C.
    § 5845(a) (defining “firearm”). Importers, manufacturers, and dealers of these
    firearms must pay a yearly tax of $500 to $1,000. 
    Id. § 5801.
    And each time one of
    these firearms is made or transferred, the statute levies a $200 tax. 
    Id. § 5811
    (“Transfer tax”); 
    id. § 5821
    (“Making tax”). But the NFA does more than lay taxes.
    To carry out the taxing scheme, it also mandates the registration of every importer,
    manufacturer, and dealer, see 
    id. § 5802,
    and of every firearm made, see 
    id. § 5822,
    or transferred, see 
    id. § 5812.
    And to ensure compliance, the statute has teeth: the
    12
    failure to abide by any of its rules is a crime punishable by up to ten years in prison
    (or a fine, or both). 
    Id. §§ 5861
    (“Prohibited acts”), 5871 (“Penalties”).
    The Supreme Court addressed Congress’s taxing-clause authority to enact the
    NFA eighty-one years ago, when a firearms dealer indicted for failing to pay the
    (then $200) annual dealer tax challenged the statute’s constitutional basis with an
    argument similar to Cox and Kettler’s. See United States v. Sonzinsky, 
    300 U.S. 506
    ,
    511 (1937). The dealer conceded that the taxing power allowed Congress to tax
    firearms dealers, yet he “insist[ed]” that the tax at issue was “not a true tax, but a
    penalty imposed for the purpose of suppressing traffic in a certain noxious type of
    firearms.” 
    Id. at 512.
    But the Constitution, according to the dealer, had reserved
    regulation of these firearms to the states, not to the federal government. 
    Id. He concluded
    that the NFA revealed its “penal and prohibitive character” by
    cumulatively taxing importers, manufacturers, dealers, and transferors. 
    Id. The Supreme
    Court rejected the dealer’s challenge, refusing to conclude that
    the NFA—on its face a taxing measure—exceeded congressional power “by virtue of
    its deterrent effect on the activities taxed.” 
    Id. at 513–14.
    “Every tax is in some
    measure regulatory,” explained the Court, and “a tax is not any the less a tax because
    it has a regulatory effect.” 
    Id. at 513.
    Unlike the child-labor tax struck down in the
    Child Labor Tax Case, the NFA tax wasn’t “a penalty resorted to as a means of
    enforcing [other] regulations.” 
    Id. (citing Bailey
    v. Drexel Furniture Co. (The Child
    Labor Tax Case), 
    259 U.S. 20
    , 35 (1922)). Rather, though the NFA contained
    registration provisions, those provisions were “obviously supportable as in aid of a
    13
    revenue purpose.” 
    Id. And because
    the $200-per-year dealer tax produced “some
    revenue,” the Court refused to ponder Congress’s motives in imposing it or to
    estimate its regulatory effect. 
    Id. at 514.
    In sum, since “it [wa]s not attended by an
    offensive regulation, and since it operate[d] as a tax,” the Court concluded that the
    NFA’s taxing scheme was “within the national taxing power.” 
    Id. Cox and
    Kettler urge us to limit Sonzinsky’s holding to the NFA of 1937, a
    statute that they claim no longer exists, and to reconsider the constitutional premise
    for today’s NFA. According to Cox and Kettler, the statute that Sonzinsky upheld
    “has morphed, over more than eight decades, to the point that the current NFA
    registration system bears virtually no resemblance to a measure designed to collect
    revenue.” Kettler’s Opening Br. at 11–12.
    Today, Cox and Kettler contend, the NFA is “far more of a gun-control
    measure than a gun-tax measure.” Cox’s Opening Br. at 53. They point out that since
    2003, the ATF has administered the NFA from the Justice Department instead of the
    Treasury Department, where the ATF and its predecessor agencies spent the
    preceding 200 years. They note that as a result, the NFA—alone in the Internal
    Revenue Code—now falls outside the purview of the Treasury Secretary. And with
    this shift in oversight, they argue, today’s NFA resembles the regulatory scheme
    struck down in the Child Labor Tax Case, which subjected employers “to inspection
    at any time not only by the taxing officers of the Treasury, the Department normally
    charged with the collection of taxes, but also by the Secretary of Labor and his
    subordinates, whose normal function is the advancement and protection of the
    14
    welfare of the 
    workers.” 259 U.S. at 37
    . Cox and Kettler thus conclude that the NFA,
    like that “so-called tax” on child labor, is really a penalty, outside Congress’s taxing
    power. The Child Labor Tax 
    Case, 259 U.S. at 37
    .
    Which agency or agencies administer a tax, however, is but one indicator
    among several in the “functional approach” to whether that tax is really—for
    constitutional purposes—a tax. See Nat’l Fed. of Indep. Bus. v. Sebelius, 
    567 U.S. 519
    , 565 (2012). And on that score, the child-labor “tax” in the Child Labor Tax
    Case had two more strikes against it: first, the tax imposed “a heavy exaction” on
    violators, equal to one tenth of a business’s yearly net income; and second, the law
    included a scienter requirement, meaning that only knowing violators had to pay the
    tax. The Child Labor Tax 
    Case, 259 U.S. at 36
    ; see also 
    Sebelius, 567 U.S. at 565
    –
    66. The sum of all three characteristics made “palpable” the law’s “prohibitory and
    regulatory effect” and convinced the Court that the so-called tax was really a penalty,
    meant to stop child labor, and fell outside Congress’s taxing-clause authority. The
    Child Labor Tax 
    Case, 259 U.S. at 37
    , 39.
    Yet Cox and Kettler don’t contend that today’s NFA exhibits either of the
    other penalty-like features of the child-labor “tax” in the Child Labor Tax Case. Nor
    need we assess which way those features point in this case, for we aren’t starting
    from a blank slate in determining whether the NFA is a constitutional tax; we’re
    starting from Sonzinsky. In upholding the NFA, Sonzinsky expressly distinguished the
    Child Labor Tax Case and similar decisions, in which “the [challenged] statute
    contain[ed] regulatory provisions related to a purported tax in such a way . . . that the
    15
    latter [wa]s a penalty resorted to as a means of enforcing the regulations.” 
    Sonzinsky, 300 U.S. at 513
    . The NFA, according to Sonzinsky, regulates only “in aid of a
    revenue purpose.” 
    Id. Only six
    years ago, Sebelius reaffirmed the NFA’s constitutional legitimacy,
    touting the statute’s “obviously regulatory” tax on sawed-off shotguns as proof that
    “taxes that seek to influence conduct are nothing new” and remain valid exercises of
    the taxing 
    power. 567 U.S. at 567
    (citing 
    Sonzinsky, 300 U.S. at 513
    ); see also 
    id. (explaining that
    even though the Affordable Care Act’s individual mandate “seeks to
    shape decisions about whether to buy health insurance,” it’s still a valid exercise of
    the taxing power). And by itself, moving the NFA’s administration from the Treasury
    Department to the Justice Department didn’t so alter the balance between the
    statute’s taxes and its regulatory provisions as to unmoor today’s NFA from the
    statute deemed constitutional in Sonzinsky and cited with approval in Sebelius.
    But Cox and Kettler’s taxing-power argument has another angle. Noting that
    Sonzinsky upheld the NFA’s dealer tax in large part because the tax produced “some
    revenue,” they dispute that the administration of today’s NFA raises any net revenue.
    
    See 300 U.S. at 514
    . Citing our decision in United States v. Dalton, 
    960 F.2d 121
    (10th Cir. 1992), they claim that a statute that doesn’t raise net revenue can’t “be
    justified under Congress’ power to raise revenue.” Kettler’s Opening Br. at 24.
    The current registration process, they argue, is “structured to avoid generating
    revenue in as many instances as possible.” 
    Id. at 19.
    They claim that increasingly
    complex registration applications, background checks, and swelling (now months-
    16
    long) delays likely discourage many from even trying to register and pay NFA taxes.
    As for those willing to run that gantlet, Cox and Kettler note that the ATF denies the
    applications of would-be registrants whom federal law prohibits from buying
    firearms, meaning that “literally tens of millions of Americans are deemed ineligible
    to pay the NFA tax.” Kettler’s Opening Br. at 18 (citing 18 U.S.C. § 922(d), which
    makes it unlawful “for any person to sell or otherwise dispose of any firearm” to
    someone who falls into any of nine categories, including felons, see 
    id. § 922(d)(1),
    and fugitives from justice, see 
    id. § 922(d)(2)).
    And what’s more, Congress hasn’t
    raised the $200 transfer fee for silencers and short-barreled rifles since 1934—not
    even to keep pace with inflation9—so, argue Cox and Kettler, “it could be said that”
    the NFA’s taxes are now “productive of no net revenue.” 
    Id. at 2
    2.
    But Dalton doesn’t stand for the proposition that Cox and Kettler attribute to
    it: that “the taxing power can no longer be the constitutional basis for the NFA when
    the $510 and $200 NFA fees no longer raise net revenue.” Kettler’s Opening Br. at 24.
    9
    Cox and Kettler recognize that Congress has raised the occupational taxes
    that importers, manufacturers, and dealers must pay.
    10
    The NFA imposes a transfer tax of $5 “on any firearm classified as any other
    weapon under [26 U.S.C.] section 5845(e).” 26 U.S.C. § 5811(a). But the weapons
    listed in Cox’s and Kettler’s indictment—silencers, a short-barreled rifle, destructive
    devices—don’t fall under § 5845(e)’s definition of “any other weapon.” 26 U.S.C.
    § 5845. They are “firearms” taxed at $200 per transfer, see § 5811(a), so the $5 rate
    is irrelevant to Cox’s and Kettler’s as-applied challenges to the NFA.
    17
    That case addressed whether due process permitted Dalton’s convictions for
    violating the NFA by possessing (26 U.S.C. § 5861(d)) and transferring (§ 5861(e))
    an unregistered machinegun, when a separate law, 18 U.S.C. § 922(o), banned the
    possession and transfer of machineguns. 
    Dalton, 960 F.2d at 122
    . To avoid running
    afoul of 26 U.S.C. § 5861(d) and (e), the NFA’s transfer provision (§ 5812) required
    the transferor to pay a tax and apply to register the machinegun. 
    Dalton, 960 F.2d at 122
    . But the transfer provision also required that applications to register illegal
    weapons be denied. 
    Id. at 123.
    Section 922(o) thus made compliance with § 5861(d)
    and (e)’s registration requirements impossible, and we agreed with Dalton “that it
    violate[d] fundamental fairness to convict him for failing to do an act which everyone
    agree[d] he could not perform.” 
    Dalton, 960 F.2d at 123
    . Weakening the premise for
    Dalton’s convictions still further, we reasoned that § 922(o) had “undercut the
    constitutional basis” of the NFA’s machinegun-registration requirement. 
    Id. at 124–
    25 (quoting United States v. Rock Island Armory, Inc., 
    773 F. Supp. 117
    , 125 (C.D.
    Ill. 1991), rejected by United States v. Ross, 
    9 F.3d 1182
    , 1194 (7th Cir. 1993),
    vacated, 
    511 U.S. 1124
    (1994)).11 We noted that Sonzinsky had upheld the NFA’s
    registration requirements as “solely in aid of collecting the tax,” so when § 922(o)
    11
    The Supreme Court returned Ross to the Seventh Circuit for reconsideration
    in light of the Court’s intervening decision in Staples v. United States, 
    511 U.S. 600
    ,
    602 (1994), which interpreted 26 U.S.C. § 5861(d) to require a defendant to know
    that the weapon that he possessed exhibited features making it a “firearm” for NFA
    purposes. Ross v. United States, 
    511 U.S. 1124
    (1994); see also United States v.
    Ross, 
    40 F.3d 144
    , 145 (7th Cir. 1994) (concluding, on remand, that failing to
    instruct the jury on this knowledge requirement warranted a new trial).
    18
    ended the registration and taxation of machineguns, it also removed “the
    constitutional base for those requirements—i.e., the power to tax.” 
    Id. at 124.
    Dalton’s convictions for possessing and transferring an unregistered machinegun in
    violation of § 5861(d) and (e), we concluded, were therefore “constitutionally
    infirm.” 
    Id. at 126.
    As later decisions have made clear, the constitutional infirmity in Dalton’s
    convictions resulted from 18 U.S.C. § 922(o)’s prohibition of the firearm at issue,
    which removed 26 U.S.C. § 5861’s constitutional footing by making registration “a
    literal and legal impossibility.” United States v. McCollom, 
    12 F.3d 968
    , 971 (10th
    Cir. 1993). Unless a separate statute criminalizes possession of a firearm, though, a
    due-process or taxing-power challenge to a § 5861(d) conviction is doomed to fail.
    See 
    id. at 970–71
    (concluding that, because no statute bans the registration of short-
    barreled shotguns, due process didn’t bar McCollum’s § 5861(d) conviction for
    possessing an unregistered sawed-off shotgun). That’s so regardless of the practical
    difficulty or unlikelihood of registering the firearm—and regardless of how little
    revenue the tax generates. See, e.g., United States v. Berres, 
    777 F.3d 1083
    , 1088
    (10th Cir. 2015) (reasoning that the registration of flash bangs isn’t a legal
    impossibility, and so rejecting a due-process challenge to Berres’s § 5861(d)
    conviction for possessing one); United States v. Eaton, 
    260 F.3d 1232
    , 1236 (10th
    Cir. 2001) (reaching the same conclusion regarding Eaton’s possession of a pipe
    bomb). And because Cox and Kettler point to no federal statutory ban on the
    19
    possession or transfer of the firearms at issue—silencers and short-barreled rifles—
    Dalton doesn’t control this case.
    Nevertheless, Cox and Kettler urge us to extend Dalton to this case by treating
    a lack of net revenue from NFA taxes on a weapon like a statutory ban on that
    weapon. As net revenue falls to zero, they argue, the NFA’s taxing purpose
    disappears, leaving only its regulatory effect, and the statute’s constitutional
    legitimacy crumbles.
    They’re correct that revenue mattered in Dalton, which reasoned that because
    of § 922(o)’s machinegun ban, the government collected none from the possession or
    transfer of 
    machineguns. 960 F.2d at 125
    . Revenue also mattered in 
    Sonzinsky, 300 U.S. at 514
    , which upheld the NFA because its dealer tax was “productive of some
    revenue,” and in 
    Sebelius, 567 U.S. at 564
    , which noted that the ACA’s shared-
    responsibility payment bore “the essential feature of any tax: It produce[d] at least
    some revenue for the Government.”
    But in each case, the constitutional question hinged on gross revenue, and it
    set the bar low—“some” gross revenue. See Minor v. United States, 
    396 U.S. 87
    , 98
    n.13 (1969) (“A statute does not cease to be a valid tax measure . . . because the
    revenue obtained is negligible . . . .”). Cox and Kettler direct us to no authority where
    a tax’s net revenue (i.e., what’s left after deducting expenses) affects its
    constitutional validity. Plus, as the government pragmatically puts it, “If the focus
    were on net revenue, then the Executive Branch could negate the constitutionality of
    a tax imposed by Congress simply through spendthrift enforcement.” Br. for the
    20
    United States at 21. While Cox and Kettler contend that the $200 transfer tax on
    silencers “no longer raise[s] net revenue,” they do not dispute that it raises some
    revenue. Kettler’s Opening Br. at 24. That’s all that Sonzinsky and Sebelius require
    (and what we deemed impossible in Dalton).
    Accordingly, though times may have changed since the Court decided
    Sonzinsky in 1937, Cox and Kettler point to no differences, either in the NFA or in
    courts’ understanding of the national taxing power, that justify departing from
    Sonzinsky’s conclusion that the NFA is a valid exercise of Congress’s power. See
    Citizens United v. FEC, 
    530 F. Supp. 2d 274
    , 278 (D.D.C. 2008) (“Only the Supreme
    Court may overrule its decisions.”); see also Rodriguez de Quijas v. Shearson/Am.
    Express, Inc., 
    490 U.S. 477
    , 484 (1989) (explaining that courts of appeals should
    follow Supreme Court precedent that “has direct application in a case” even if that
    precedent “appears to rest on reasons rejected in some other line of decisions” and
    should “leav[e] to th[e] Court the prerogative of overruling its own decisions”). We
    therefore conclude that the NFA falls within Congress’s power to tax.12
    12
    Other circuits uniformly agree. See, e.g., United States v. Spoerke, 
    568 F.3d 1236
    , 1245–46 (11th Cir. 2009); United States v. Vill. Ctr., 
    452 F.3d 949
    , 950 (8th
    Cir. 2006); United States v. Lim, 
    444 F.3d 910
    , 913–14 (7th Cir. 2006); United States
    v. Thompson, 
    361 F.3d 918
    , 921 (6th Cir. 2004); United States v. Grier, 
    354 F.3d 210
    , 215 (3d Cir. 2003); United States v. Gresham, 
    118 F.3d 258
    , 261–62 (5th Cir.
    1997); United States v. Dodge, 
    61 F.3d 142
    , 145–46 (2d Cir. 1995); United States v.
    Aiken, 
    974 F.2d 446
    , 449–50 (4th Cir. 1992); United States v. Giannini, 
    455 F.2d 147
    , 148 (9th Cir. 1972).
    21
    2. Does the National Firearms Act Comport with the Second
    Amendment?
    Cox and Kettler next challenge the NFA on the ground that it violates the
    Second Amendment. Both contend that their NFA convictions stem from activities
    that the Second Amendment protects—possessing short-barreled rifles and making,
    selling, transferring, and possessing silencers—yet their challenges then diverge.
    While Cox urges us to follow District of Columbia v. Heller, 
    554 U.S. 570
    , 595, 626
    (2008), and to apply means–end scrutiny to the NFA, Kettler argues that under Cox v.
    New Hampshire, 
    312 U.S. 569
    , 577 (1941), and Murdock v. Pennsylvania, 
    319 U.S. 105
    , 113 (1943), the NFA impermissibly taxes the exercise of his constitutional right
    to bear arms.
    We begin, as Cox suggests, with Heller, tracing the scope of the Second
    Amendment and asking whether it permits the NFA regulations at issue. Then we
    turn to Kettler’s argument and consider the impact of the Cox–Murdock rule on our
    analysis.
    a. The Scope of the Second Amendment under Heller
    “A well regulated Militia, being necessary to the security of a free State, the
    right of the people to keep and bear Arms, shall not be infringed.” U.S. Const.
    amend. II. This amendment confers an individual right to keep and carry arms, but
    that doesn’t mean that it gives everyone the absolute right to carry any weapon, in
    any manner, for any purpose. 
    Heller, 554 U.S. at 595
    , 626.
    22
    The right to keep and carry arms, like other constitutional guarantees, has
    limits, and in Heller, the Court identified two venerable ones. See 
    id. at 595,
    626–27.
    First, since the nineteenth century, the Second Amendment has coexisted with a
    range of firearms regulations. 
    Id. at 627
    & n.26. Heller refused “to cast doubt on
    longstanding prohibitions on the possession of firearms by felons and the mentally
    ill, or laws forbidding the carrying of firearms in sensitive places such as schools and
    government buildings, or laws imposing conditions and qualifications on the
    commercial sale of arms.” 
    Id. at 626–27.
    Second, the Court reasoned that “the
    historical tradition of prohibiting the carrying of dangerous and unusual weapons”
    supported limiting the Second Amendment’s protection to weapons “in common use
    at the time” of ratification. 
    Id. at 627
    (internal quotation marks and citations omitted)
    (quoting United States v. Miller, 
    307 U.S. 174
    , 179 (1939)). That means, according to
    Heller, that “those weapons not typically possessed by law-abiding citizens for
    lawful purposes”—short-barreled shotguns, for instance—fall outside the scope of
    the amendment. 
    Id. at 625;
    see also 
    Miller, 307 U.S. at 178
    (“[W]e cannot say that
    the Second Amendment guarantees the right to keep and bear [a short-barreled
    shotgun].”).
    Yet within these limits, the Second Amendment takes some firearm regulations
    “off the [constitutional] table.” 
    Heller, 554 U.S. at 636
    . The law at issue in Heller,
    the District of Columbia’s total ban on handgun possession in the home, represents
    the archetype of an unconstitutional firearm regulation. See 
    id. at 628–29.
    The law
    not only prohibited “an entire class of ‘arms’” that Americans “overwhelmingly”
    23
    choose to keep and to use for “the core lawful purpose of self-defense,” but it
    extended that prohibition “to the home, where the need for defense of self, family,
    and property is most acute.” 
    Id. at 628,
    630. Such a ban, Heller concluded, “would
    fail constitutional muster” no matter what level of scrutiny the Court applied. 
    Id. at 628–29
    & 628 n.27. Heller thus highlighted some traits of an unconstitutional
    regulation, but it left open how future courts should sort the constitutional from the
    unconstitutional.
    As Cox points out though, our decision in United States v. Reese interpreted
    Heller to “‘suggest[] a two-pronged approach to Second Amendment challenges’ to
    federal statutes.” 
    627 F.3d 792
    , 800 (10th Cir. 2010) (quoting United States v.
    Marzzarella, 
    614 F.3d 85
    , 89 (3d Cir. 2010), and citing United States v. Skoien, 
    614 F.3d 638
    , 641–42 (7th Cir. 2010) (en banc)). Under the two-pronged approach, the
    reviewing court first asks: Does the challenged law burden conduct within the scope
    of the Second Amendment’s guarantee? 
    Id. (quoting Marzzarella,
    614 F.3d at 89). If
    not, then the inquiry ends there. 
    Id. at 800–01
    (quoting 
    Marzzarella, 614 F.3d at 89
    ).
    But if the law burdens protected conduct, then “[the court] must evaluate the law
    under some form of means-end scrutiny.” 
    Id. at 801
    (alteration in original) (quoting
    
    Marzzarella, 614 F.3d at 89
    ). The law is constitutional only if it survives that
    scrutiny. 
    Id. (quoting Marzzarella,
    614 F.3d at 89).
    We agree with Cox that Reese’s two-pronged approach provides a workable
    means of evaluating his Second Amendment challenges to the NFA’s regulation of
    (1) short-barreled rifles, (2) silencers, and (3) the making and selling of firearms. We
    24
    thus begin by asking whether each regulated activity falls within the scope of the
    Second Amendment’s guarantee. See 
    Reese, 627 F.3d at 800
    –01. (If we answer
    “yes,” then we will address whether the NFA’s regulation of that activity survives
    means–end scrutiny. 
    Id. at 801
    .)
    i.   Short-barreled rifles
    Cox argues that because short-barreled rifles are neither unusual nor especially
    dangerous, possessing them falls within the Second Amendment’s ambit. He asserts
    that legal uses of short-barreled rifles include “collecting, hunting, and home
    defense.” Cox’s Opening Br. at 48. And when it comes to the risk of violence, Cox
    claims that compared to all rifles (short- or long-barreled), “non-restricted pistols are
    far more commonly used in firearm-related crime.” 
    Id. at 49
    (quoting James A.
    D’Cruz, Half-Cocked: The Regulatory Framework of Short-Barrel Firearms, 40
    Harv. J.L. & Pub. Pol’y 493, 518 & n.161 (May 2017)).
    That handguns may bear a higher correlation to crime than rifles do, however,
    implies nothing about whether short-barreled rifles, in particular, are dangerous and
    unusual. More telling is Heller’s conclusion that short-barreled shotguns—close
    analogues to short-barreled rifles—belong in that category of weapons not typically
    possessed by law-abiding citizens for lawful purposes and, therefore, not protected
    by the Second 
    Amendment. 554 U.S. at 624
    –25 (discussing 
    Miller, 307 U.S. at 178
    );
    accord United States v. Artez, 290 F. App’x 203, 208 (10th Cir. 2008) (noting that
    Heller expressly foreclosed Artez’s argument that the Second Amendment protected
    his possession of a sawed-off shotgun). And since Heller, many courts have
    25
    explained that a long gun with a shortened barrel is both dangerous, because “its
    concealability fosters its use in illicit activity,” and unusual, “because of its
    heightened capability to cause damage.” 
    Marzzarella, 614 F.3d at 95
    ; see also, e.g.,
    United States v. Amos, 
    501 F.3d 524
    , 531 (6th Cir. 2007) (McKeague, J., dissenting)
    (“[A] sawed-off shotgun can be concealed under a large shirt or coat. . . . [T]he
    combination of low, somewhat indiscriminate accuracy, large destructive power, and
    the ability to conceal . . . makes a sawed-off shotgun useful for only violence against
    another person, rather than, for example, against sport game.”).
    Though these cases dealt with short-barreled shotguns, rather than short-
    barreled rifles, Cox has offered no meaningful distinction between the two. We need
    not opine on whether a sufficient factual record could be developed to distinguish short-
    barreled rifles from short-barreled shotguns. On the record and argument before us, we
    take our cue from Heller and conclude that the possession of short-barreled rifles
    falls outside the Second Amendment’s guarantee.
    ii.   Silencers
    Next, we turn to silencers, which both Cox and Kettler contend merit Second
    Amendment protection. They argue that silencers are in common use (more common,
    says Kettler, than handguns were in the District of Columbia when the Court decided
    Heller) and that they’re very rarely used to commit crimes—“except on television
    and in the movies.” Kettler’s Opening Br. at 34. Further, they claim that silencers
    protect the shooter’s (and bystanders’) hearing and, “by reducing muzzle flinch and
    the disorientation that can follow a loud shot,” can improve accuracy. Cox’s Opening
    26
    Br. at 45. And because the alternative—donning earmuffs—takes up precious time
    and suppresses surrounding sounds, they argue that these hearing-protection and
    accuracy benefits make silencers particularly valuable for “the core lawful purpose of
    home defense.” See 
    Heller, 554 U.S. at 630
    .
    But a more basic question remains: Even if silencers are commonly used by
    law-abiding citizens for lawful purposes, are they a type of instrument protected by
    the Second Amendment? According to Heller, “the Second Amendment extends,
    prima facie, to all instruments that constitute bearable 
    arms.” 554 U.S. at 582
    (emphasis added). An instrument need not have existed at the time of the founding to
    fall within the amendment’s ambit, but it must fit the founding-era definition of an
    “Arm[].” 
    Id. at 581
    (citing two dictionaries from the eighteenth, and one from the
    nineteenth, century). Then and now, that means, the Second Amendment covers
    “[w]eapons of offence, or armour of defence,” or “any thing that a man wears for his
    defence, or takes into his hands, or useth in wrath to cast at or strike another.” 
    Id. at 581
    (alteration in original) (citations omitted). A silencer is a firearm accessory; it’s
    not a weapon in itself (nor is it “armour of defence”). Accordingly, it can’t be a
    “bearable arm” protected by the Second Amendment.13
    13
    Though we needn’t decide the issue, we note that the government cites
    authority concluding that silencers are dangerous and unusual, the type of “arm”
    traditionally excluded from the Second Amendment’s protection. See, e.g., United
    States v. McCartney, 357 F. App’x 73, 76 (9th Cir. 2009) (finding silencers even
    more dangerous than machineguns, for “[s]ilencers . . . are not ‘typically possessed
    by law-abiding citizens for lawful purposes,’ and are less common than either short-
    barreled shotguns or machine guns” (quoting 
    Heller, 554 U.S. at 625
    )); United States
    27
    Thus, because silencers are not “bearable arms,” they fall outside the Second
    Amendment’s guarantee.
    iii.   Making and selling firearms
    Finally, Cox argues that the Second Amendment protects the making and
    selling of silencers. For two reasons, however, we disagree.
    As a threshold matter, Heller endorsed “laws imposing conditions and
    qualifications on the commercial sale of arms” as one of the limitations on the right
    to bear 
    arms. 554 U.S. at 626
    –27. The NFA’s requirements that firearms dealers and
    manufacturers register and pay taxes annually fit neatly into that category of
    “presumptively lawful regulatory measures.” 
    Id. at 627
    n.26; see 26 U.S.C. §§ 5801
    (imposing an annual tax of $500 to $1,000 on “every importer, manufacturer, and
    dealer in firearms”), 5802 (requiring “each importer, manufacturer, and dealer in
    firearms” to register every year with the Secretary of the Treasury). Those
    requirements, therefore, don’t infringe the right to bear arms.
    v. Garnett, 
    2008 WL 2796098
    , at *4 (E.D. Mich. 2008) (concluding that “nothing in
    [Heller] . . . casts doubt on the constitutionality of” the NFA’s regulation of
    silencers); see also Eugene Volokh, Implementing the Right to Keep and Bear Arms
    for Self-Defense: An Analytical Framework and a Research Agenda, 56 UCLA L.
    Rev. 1443, 1489 & n.187 (2009) (“Bans on silencers . . . would . . . likely be
    constitutional because they don’t materially burden self-defense.” (citing People v.
    Brown, 
    235 N.W. 245
    , 246–47 (Mich. 1933) (upholding a ban on silencers, among
    other weapons, because the ban focused on “a partial inventory of the arsenal of the
    ‘public enemy,’ the ‘gangster’”; it didn’t include “weapons usually relied upon by
    good citizens for defense or pleasure”)).
    28
    More importantly, though, the indictment charged Cox with, and the jury
    found him guilty of, engaging in business as a dealer or manufacturer of silencers in
    violation of the NFA. And as we’ve already concluded, the right to bear arms doesn’t
    extend to silencers. Even if the Second Amendment covers the right to buy and sell
    arms in the abstract, it can’t in practice protect the right to buy and sell instruments,
    such as silencers, that fall outside its ambit. Thus, as they apply to Cox in particular,
    the NFA’s taxation and registration requirements for firearms manufacturers and
    dealers don’t burden protected conduct.
    *      *      *
    In sum, the Second Amendment protects neither (1) short-barreled rifles, nor
    (2) silencers, nor (3) the business of manufacturing and dealing in silencers, so the
    NFA’s regulation of these activities doesn’t burden protected conduct. Our analysis
    thus ends at its first step, and we needn’t test the challenged regulations under any
    form of means–end scrutiny. See 
    Reese, 627 F.3d at 800
    –01.
    b. Applying the Rule of Cox v. New Hampshire and Murdock v.
    Pennsylvania to Second Amendment Rights
    For the first time on appeal, Cox and Kettler urge us to find that NFA taxes
    violate the Second Amendment by “impos[ing] a charge for the enjoyment of a right
    granted by the federal constitution.” 
    Murdock, 319 U.S. at 113
    . Under Murdock and
    Cox, seminal cases in the Court’s “fee jurisprudence,” the government may collect a
    fee to defray administrative and maintenance costs associated with the exercise of a
    constitutional (usually First Amendment) right, but it can’t impose a general revenue
    29
    tax on the exercise of such a right. Compare 
    Murdock, 319 U.S. at 113
    (striking
    down a license tax on the exercise of the First Amendment right to free speech), with
    
    Cox, 312 U.S. at 576
    –77 (upholding a parade-licensing fee that the state charged “to
    meet the expense incident to the administration of [the parade] and to the
    maintenance of the public order”).
    When they raised the Second Amendment in the district-court proceedings,
    neither Cox nor Kettler cited the Court’s fee jurisprudence, so the government urges
    us to review this argument for plain error. But it doesn’t matter whether we review
    for plain error or not, because the district court didn’t err (plainly or otherwise) in not
    applying the framework of Murdock and Cox.
    As the government notes, neither this court nor the Supreme Court has applied
    Murdock or Cox in the Second Amendment context. To analyze Second Amendment
    challenges to federal statutes, we have used Reese’s two-step test, borrowed from the
    Third Circuit, which does not incorporate the Court’s fee jurisprudence. See 
    Reese, 627 F.3d at 800
    –01 (concluding that Heller “suggests a two-pronged approach to
    Second Amendment challenges,” which asks whether the challenged law burdens
    protected conduct and, if so, whether it passes muster “under some form of means-
    end scrutiny” (quoting 
    Marzzarella, 614 F.3d at 89
    )).
    We recognize that other circuits have imported fee-jurisprudence principles to
    their Second Amendment analyses. See, e.g., Bauer v. Becerra, 
    858 F.3d 1216
    , 1225
    (9th Cir. 2017) (applying the fee-jurisprudence framework and concluding that fees
    supporting an extended background-check program “can fairly be considered an
    30
    ‘expense[] of policing the activities in question,’ or an ‘expense incident to . . . the
    maintenance of public order in the matter licensed’” (alterations in original) (quoting
    
    Murdock, 319 U.S. at 113
    –14, and 
    Cox, 312 U.S. at 577
    )); Kwong v. Bloomberg, 
    723 F.3d 160
    , 165 (2d Cir. 2013) (deciding that “the Supreme Court’s First Amendment
    fee jurisprudence provides the appropriate foundation for addressing” the plaintiffs’
    challenge to a handgun-licensing fee). But this appeal isn’t the right vehicle to test
    that approach in our circuit, given our conclusion that the Second Amendment covers
    neither silencers nor short-barreled rifles. NFA taxes on the possession, transfer, and
    manufacture of these items do not constitute “charge[s] for the enjoyment of a right
    granted by the federal constitution,” so they need not be measured against
    administrative costs or the expense of maintaining public order. 
    Murdock, 319 U.S. at 113
    .
    *      *      *
    For these reasons, we conclude that the NFA comports with Cox’s and
    Kettler’s Second Amendment right to bear arms.
    B. Kansas’s Second Amendment Protection Act
    The validity of the Second Amendment Protection Act has never been at issue
    in this case, yet the statute has played an outsized role since the case began. Now on
    appeal, Cox and Kettler both contend—albeit through differing theories—that the
    district court reversibly erred in ruling that they couldn’t use their reliance on the
    SAPA as a defense to breaking federal firearms laws. Separately and additionally,
    31
    Kettler claims that the SAPA caused a clash between the Governor of Kansas and the
    U.S. Attorney General, which led, unjustly, to his prosecution.
    The availability and scope of any defense based on the SAPA present legal
    questions that we review de novo. Cf. United States v. Hernandez-Urista, 
    9 F.3d 82
    ,
    83, 84 (10th Cir. 1993) (reviewing de novo whether a good-faith defense required
    that the defendant’s good-faith belief be reasonable). We start our analysis with an
    overview of the SAPA, and then turn to Cox’s and Kettler’s arguments.
    The SAPA spans about three pages of the Kansas Register, but its most oft-
    quoted section in this appeal is § 4(a), which states,
    A personal firearm, a firearm accessory or ammunition that is
    manufactured commercially or privately and owned in Kansas and that
    remains within the borders of Kansas is not subject to any federal law,
    treaty, federal regulation, or federal executive action, including any
    federal firearm or ammunition registration program, under the authority
    of congress to regulate interstate commerce. It is declared by the
    legislature that those items have not traveled in interstate commerce. This
    section applies to a firearm, a firearm accessory or ammunition that is
    manufactured commercially or privately and owned in the state of
    Kansas.
    Second Amendment Protection Act § 4(a) (codified at Kan. Stat. Ann. § 50-1204(a)).
    The SAPA also:
     declares “[a]ny act, law, treaty, order, rule or regulation of the
    government of the United States” that violates the Second Amendment
    “null, void and unenforceable in the state of Kansas,” Kan. Stat. Ann.
    § 50-1206(a);
     prohibits Kansas officials from enforcing, or attempting to enforce,
    “any act, law, treaty, order, rule or regulation of the government of the
    United States regarding any personal firearm, firearm accessory or
    ammunition that is manufactured commercially or privately and
    32
    owned in the state of Kansas and that remains within the borders of
    Kansas,” Kan. Stat. Ann. § 50-1206(b); and,
     subjects any federal official who enforces, or tries to enforce, “any
    act, law, treaty, order, rule or regulation of the government of the
    United States regarding a firearm, a firearm accessory, or ammunition
    that is manufactured commercially or privately and owned in the state
    of Kansas and that remains within the borders of Kansas” to
    prosecution for “a severity level 10 nonperson felony,” Kan. Stat.
    Ann. § 50-1207.
    1. Is Reliance on the Second Amendment Protection Act a Defense?
    Cox and Kettler both claim (and the government doesn’t dispute) that they
    understood the SAPA to insulate from federal regulation the making, possession, and
    transfer of firearms within Kansas’s borders. That was a mistake—the NFA’s taxes
    and registration requirements apply to all statutorily defined firearms—yet Cox and
    Kettler argue that their reliance on the SAPA still provided a defense to the charges
    that they violated the NFA.
    The district court permitted mention of the SAPA during trial “as part of the
    res gestae of the offenses,” but it didn’t let Cox and Kettler claim reliance on the
    SAPA as a defense. Cox R. vol. 1 at 194–95.14 In doing so, it relied on settled law.
    14
    Cox specifically notes that the court: (1) denied his request to introduce a
    copy of the SAPA displayed in his store; (2) refused to instruct the jury that he was
    raising, “as a complete defense[,] . . . that he acted in ‘good faith’ in his belief he was
    following State law [the SAPA] that superseded application of the federal law”
    charged in the indictment, Cox R. vol. 1 at 207; (3) instructed the jury, over his and
    Kettler’s objections, that to establish the offenses of possession (26 U.S.C.
    § 5861(d)) or transfer (§ 5861(e)) of an unregistered firearm, “[t]he government
    [wa]s not required to prove that the defendant knew that the firearm was not
    registered or had to be registered,” Cox R. vol. 1 at 287, 290; and (4) instructed the
    jury, over Cox’s and Kettler’s objections, that because the government needn’t prove
    33
    The NFA’s list of “[p]rohibited acts” in 26 U.S.C. § 5861 is silent regarding
    violators’ mental state; the statute just makes it “unlawful for any person” to be a
    firearms dealer; or to make, receive, possess, or transfer a firearm in violation of the
    NFA’s registration or other provisions. Silence, though, doesn’t necessarily mean
    “that Congress intended to dispense with a conventional mens rea element, which
    would require that the defendant know the facts that make his conduct illegal.”
    Staples v. United States, 
    511 U.S. 600
    , 605 (1994) (citing United States v. Balint, 
    258 U.S. 250
    , 251 (1922)). In the context of § 5861(d) in particular, which makes it
    unlawful “to receive or possess” an unregistered firearm, the government must prove
    that a defendant knew the features of the firearm that made it a “firearm” under the
    NFA. 
    Id. at 619.
    A defendant need not, however, know that the firearm was
    unregistered. 
    Id. at 609
    (citing United States v. Freed, 
    401 U.S. 601
    , 607–09 (1971)).
    “Knowledge of whether the gun was registered is so closely related to knowledge of
    the registration requirement that requiring the Government to prove the former would
    in effect require it to prove knowledge of the law.” 
    Id. at 622
    n.3 (Ginsburg, J.,
    concurring). And as a general rule, ignorance of the law or a mistake of law is no
    defense to criminal prosecution. Cheek v. United States, 
    498 U.S. 192
    , 199 (1991);
    a defendant’s knowledge of the NFA’s registration requirements, “it [wa]s not a
    defense to a charge under [26 U.S.C.] § 5861 that a defendant may have believed,
    based on Kansas law, that the National Firearms Act did not require registration of a
    firearm,” Cox R. vol. 1 at 295.
    34
    accord 
    Staples, 511 U.S. at 622
    n.3 (Ginsburg, J., concurring) (citing 
    Freed, 401 U.S. at 612
    –14 (Brennan, J., concurring)).
    That general mistake-of-law rule forecloses Cox and Kettler’s proposed
    defense—that they wrongly believed, in reliance on the SAPA, that federal firearms
    regulations didn’t reach their Kansas-centric activities. To be criminally liable, Cox
    and Kettler didn’t need to know that their acts were “illegal, wrong, or
    blameworthy.” 
    Freed, 401 U.S. at 612
    (Brennan, J., concurring). But Cox and Kettler
    urge us not to apply the general rule here. Something about the SAPA, they claim,
    changes things. Their arguments differ enough that we address them separately.
    a. Cox’s Argument: A Due Process Problem
    Cox grounds his argument in the due-process principle that a defendant
    deserves “a meaningful opportunity to present a complete defense.” Cox’s Opening
    Br. at 23–24 (quoting California v. Trombetta, 
    467 U.S. 479
    , 485 (1984)). He argues
    for a limited exception, in cases like his, to the rule that ignorance of the law isn’t a
    defense. If (1) “the accused’s conduct is subject to facially conflicting state and
    federal laws,” and if (2) “the state law has not (yet) been held inapplicable, inferior,
    or illegitimate by any court,” then, he claims, “the accused’s good-faith reliance on
    the state law is a complete defense to criminal charges brought under the federal
    law.” 
    Id. at 2
    4.
    Cox asserts that in prior cases, the Supreme Court has endorsed similar
    defenses based on notions of due process, notice, and fairness. In an appeal brought
    by a different Mr. Cox, for example, the Court concluded that the Due Process Clause
    35
    prevented the government from “convicting a citizen for exercising a privilege which
    the [government] had clearly told him was available to him.” Cox v. Louisiana, 
    379 U.S. 559
    , 571 (1965) (quoting Raley v. Ohio, 
    360 U.S. 423
    , 426 (1959)). In Cox, “the
    highest police officials of the city, in the presence of the Sheriff and Mayor,” had
    told demonstrators, including Mr. Cox, that they could meet at a spot about 101 feet
    from the courthouse steps, but after the demonstration (at that spot), the state
    prosecuted Cox for violating a statute banning picketing “in or near” a courthouse.
    
    Id. at 560,
    571. Based on the public officials’ actions, the Court struck Cox’s
    conviction, reasoning that to sustain it “would be to sanction an indefensible sort of
    entrapment by the State.” 
    Id. at 571
    (quoting 
    Raley, 360 U.S. at 426
    ); see also United
    States v. Pa. Indus. Chem. Corp., 
    411 U.S. 655
    , 657, 673–74 (1973) (allowing a
    corporation to assert, as a defense to a charge of polluting a river in violation of the
    Rivers and Harbors Act, that it had relied on the Army Corps of Engineers’—the
    administrative agency responsible for interpreting the Act—“longstanding
    administrative construction of [the Act] as limited to water deposits that impede or
    obstruct navigation”).
    In this circuit, courts treat such due-process challenges as claims of entrapment
    by estoppel. See United States v. Hardridge, 
    379 F.3d 1188
    , 1192 (10th Cir. 2004)
    (citing 
    Raley, 360 U.S. at 426
    , and 
    Cox, 379 U.S. at 571
    ). To win an entrapment-by-
    estoppel claim, a defendant criminally prosecuted for an offense must prove (1) that a
    government agent actively misled him about the state of the law defining the offense;
    (2) that the government agent was “responsible for interpreting, administering, or
    36
    enforcing the law defining the offense”; (3) that the defendant actually relied on the
    agent’s misleading pronouncement in committing the offense; and (4) that the
    defendant’s reliance was “reasonable in light of the identity of the agent, the point of
    law misrepresented, and the substance of the misrepresentation.” 
    Id. (quoting United
    States v. Gutierrez-Gonzalez, 
    184 F.3d 1160
    , 1167 (10th Cir. 1999), and United
    States v. Nichols, 
    21 F.3d 1016
    , 1018 (10th Cir. 1994)).
    Here, Cox wouldn’t be able to prove either (1) that the misleading government
    agent (the Kansas legislature) was responsible for interpreting, administering, or
    enforcing the law defining the offense (the NFA) or (2) that his reliance on the
    misleading pronouncement (the SAPA) was reasonable in light of the circumstances.
    First, unlike the police in Cox, who enforced the anti-picketing law, or the Army
    Corps of Engineers in Pennsylvania Industrial Chemical, which administered the
    Rivers and Harbors Act, the Kansas legislature (which wrote the SAPA) isn’t
    responsible for administering or enforcing the NFA (or any other federal law).
    Second, irrespective of the government agent’s identity, the substance of the SAPA’s
    misrepresentation made Cox’s reliance on it unreasonable. Section 4(a) of the SAPA
    expressly states that certain firearms and accessories, if kept in Kansas, aren’t
    “subject to any federal law, treaty, federal regulation, or federal executive action,
    including any federal firearm or ammunition registration program, under the
    authority of congress to regulate interstate commerce. It is declared by the legislature
    that those items have not traveled in interstate commerce.” Kan. Stat. Ann.
    37
    § 50-1204(a) (emphases added). But the SAPA says nothing about laws, such as the
    NFA, passed under Congress’s authority to tax.
    Cox counters that this reading of the SAPA “ignores provisions in the Act that
    prohibit both state and federal actors from enforcing ‘any’ federal firearms laws or
    regulations with respect to local firearms.” Cox’s Reply Br. at 2–3 (citing Kan. Stat.
    Ann. §§ 50-1206(b), 1207). But Cox is wrong that “[n]o Commerce Clause limit
    appears” in these provisions, which prohibit state officials from, and subject federal
    officials to prosecution for, enforcing or attempting to enforce federal laws against
    any firearm, accessory, or ammunition “that is manufactured commercially or
    privately and owned in the state of Kansas and that remains within the borders of
    Kansas.” Cox’s Reply Br. at 3; Kan. Stat. Ann. §§ 50-1206(b), 1207 (emphases
    added). These provisions protect only homegrown, local firearms, so the Kansas
    legislature didn’t need to utter the magic words, “Commerce Clause,” to make clear
    its intent to preserve constitutional limits on the federal government’s power over
    intrastate activity. Kansas wasn’t considering, and didn’t purport to limit, Congress’s
    taxing-clause authority. Any other interpretation ignores the SAPA’s emphasis on the
    local nature of the firearms’ (and accessories’) manufacture and ownership.
    Cox, therefore, can’t use the SAPA to establish an entrapment-by-estoppel
    defense in this case. Cf. 
    Hardridge, 379 F.3d at 1192
    –96 (rejecting representations
    about the application of federal firearms laws made (1) by the Kansas City Police
    Department, (2) by the defendant’s state-court sentencing judge, and (3) by a licensed
    federal firearms dealer as bases for an entrapment-by-estoppel defense); Gutierrez-
    38
    
    Gonzalez, 184 F.3d at 1168
    –69 (denying an entrapment-by-estoppel defense based on
    alleged misrepresentations made (1) by a private entity that assisted deported,
    indigent aliens, because the entity wasn’t a government agency and because the
    defendant’s reliance on its misrepresentations wasn’t reasonable given the
    defendant’s admission that he was in the country illegally, and (2) by an immigration
    official, because the defendant couldn’t reasonably form the belief that he was in the
    U.S. legally merely from the official’s failure to arrest him “on the spot”).
    Nor do notions of due process warrant expanding entrapment by estoppel and
    creating a new, estoppel-like defense to fit situations in which “the accused’s conduct
    is subject to facially conflicting state and federal laws” and the accused acts in good-
    faith reliance on the state law. Cox’s Opening Br. at 24. Nothing about a statute
    makes reliance on its pronouncements more consequential than reliance on a
    government agent’s non-statutory statements.15 And before we apply the doctrine of
    15
    According to Cox, “[t]he collective judgment of an entire state legislature,
    regardless of jurisdiction, is surely more trustworthy than the advice of an extra-
    jurisdictional individual official.” Cox’s Opening Br. at 30. But the superiority of
    collective judgments is beside the point. State legislatures have no special expertise in,
    and aren’t charged with enforcing, federal law. State legislators are more likely to
    consider their duty to promote their constituents’ policy preferences than to expound on
    the reach of federal law.
    Nor is Cox’s analogy to the Fourth Amendment context persuasive. There, the
    Court has often deemed it reasonable for law-enforcement officers to rely on
    legislative pronouncements in forming probable cause. See, e.g., 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.”). But whether an officer’s belief was
    reasonable for probable-cause purposes is a very different question, with very
    39
    estoppel against the government, due process requires us to weigh the needs of
    society against the “natural sympathy” that we may feel toward defendants like Cox
    and Kettler, who have been prosecuted for conduct that, based on a state statute’s
    assurances, they believed was lawful. 
    Hardridge, 379 F.3d at 1194
    . Application of
    the estoppel doctrine is justified only if it doesn’t “interfere with underlying
    government policies or unduly undermine the correct enforcement of a particular law
    or regulation.” United States v. Browning, 
    630 F.2d 694
    , 702 (10th Cir. 1980) (citing
    27 A.L.R. Fed. 702 (1976)). Here, though, allowing state legislatures to estop the
    federal government from prosecuting its laws would upset the balance of powers
    between states and the federal government and contravene the Supremacy Clause.
    See U.S. Const. art. VI. We can’t countenance that result, so we decline to adopt
    Cox’s proposed defense.
    Accordingly, we reject Cox’s argument that due process required that he be
    able to present his reliance on the SAPA as a defense.
    b. Kettler’s Argument: Mens Rea and the Model Penal Code’s
    Approach
    Kettler, in turn, focuses on the mens rea element of possessing an unregistered
    firearm (in his case, a silencer) in violation of 26 U.S.C. § 5861(d). He claims that
    the “jurisdictional dispute between sovereigns” over the SAPA “demands a more
    different consequences, than whether a defendant’s reliance was reasonable for
    estoppel purposes. So different, in fact, that answering the former doesn’t help
    answer the latter.
    40
    thoughtful analysis of the mens rea element of 26 U.S.C. § 5861 than given by the
    court below.” Kettler’s Opening Br. at 50. Because possession of an unregistered
    silencer is a “morally indifferent” act (“malum prohibitum, not malum in se”), he
    contends, the mens rea element should yield to a mistake-of-law defense premised on
    the Model Penal Code’s approach. 
    Id. at 53.16
    Section 2.04(3) of the Model Penal Code, titled “Ignorance or Mistake,”
    provides,
    A belief that conduct does not legally constitute an offense is a defense
    to a prosecution for that offense based upon such conduct when:
    ...
    (b) [the actor] acts in reasonable reliance upon an official statement of
    the law, afterward determined to be invalid or erroneous, contained in
    (i) a statute or other enactment; (ii) a judicial decision, opinion or
    judgment; (iii) an administrative order or grant of permission; or (iv) an
    official interpretation of the public officer or body charged by law with
    responsibility for the interpretation, administration or enforcement of the
    law defining the offense.
    Model Penal Code § 2.04(3) (Am. Law Inst. 2017) (emphasis added).
    According to the explanatory note, this subsection “establishes a limited
    exception to the principle . . . that culpability is not generally required as to the
    illegality of the actor’s conduct.” 
    Id. § 2.04
    Explanatory Note. But the drafters
    delineated this exception “narrowly . . . so as to induce fair results without undue risk
    16
    Cox also mentions the Model Penal Code, claiming that it’s consistent with
    his proposed good-faith defense. And Cox, too, argues that NFA offenses aren’t
    inherently immoral, a trait that, he claims, “weighs in favor of recognizing his [good-
    faith] defense.” Cox’s Opening Br. at 34. To avoid duplicating any analysis, we
    address both points only once, here.
    41
    of spurious litigation.” 
    Id. Thus, for
    instance, § 2.04(3)(b)(iv) permits reliance on an
    “official statement of the law” contained in an “official interpretation of the public
    officer or body” only if the interpreting officer or body is “charged by law with
    responsibility for the interpretation, administration or enforcement of the law
    defining the offense.”
    Yet unlike paragraph (b)(iv) of § 2.04(3), paragraph (b)(i) does not expressly
    limit the “statute[s] or other enactment[s]” on whose pronouncements a defendant
    may “act in reasonable reliance.” Model Penal Code § 2.04(3)(b)(i). So, Kettler
    contends, paragraph (b)(i) permits reliance on a statute (like the SAPA) regardless of
    the enacting legislature’s jurisdiction, “suppl[ying] a defense directly supporting [his]
    case.” Kettler’s Opening Br. at 54.
    We disagree. The drafters of the Model Penal Code’s ignorance-or-mistake-of-
    law defense intended only a narrow exception in the interest of fair results. See
    Model Penal Code § 2.04(3) Introductory Note. Thus, the code’s failure to restrict
    reliance on statutes to those passed under the same authority as the law defining the
    offense probably reflects that the drafters weren’t considering our circumstance, not
    that they intended to allow state governments to estop the federal government from
    enforcing its laws. After all, the plain language of the code requires “reasonable
    reliance upon an official statement of the law.” 
    Id. § 2.04
    (3)(b) (emphases added). A
    state legislature’s statement about the reach of federal law is hardly an “official”
    statement of federal law, and to rely on such a statement is not reasonable.
    42
    Ultimately, however, the Model Penal Code isn’t the law in this circuit. Like
    Cox’s, Kettler’s claim sounds in this circuit’s doctrine of entrapment by estoppel. See
    
    Gutierrez-Gonzalez, 184 F.3d at 1166
    –68. And we’ve already concluded, in resolving
    Cox’s claim, that reliance on the SAPA can’t sustain an entrapment-by-estoppel
    defense in these cases. 
    See supra
    Section B.1.a. It’s fatal to their proposed defense
    that “in light of the identity of the agent, the point of law misrepresented, and the
    substance of the misrepresentation,” Cox’s and Kettler’s reliance on the SAPA was
    not reasonable. 
    Nichols, 21 F.3d at 1018
    .
    Nor does Kettler’s characterization of an NFA offense as “malum prohibitum,”
    or wrong only because of a statutory proscription, justify broadening the entrapment-
    by-estoppel doctrine’s (or the Model Penal Code’s) exception to the rule that a
    mistake of law generally provides no defense to a criminal prosecution. Kettler’s
    Opening Br. at 52. Kettler claims that “everyone knows the laws of the Creator, as
    they are written in the created order and imprinted by the Creator on every man” and
    that, as a result, the general mistake-of-law rule applies only to offenses that are mala
    in se (inherently wrong), not mala prohibita. 
    Id. (citing Romans
    1:18–20). But he
    cites no legal precedent carving out such an exception.
    In Cheek, the Court explained the general mistake-of-law rule’s provenance:
    “[b]ased on the notion that the law is definite and knowable, the common law
    presumed that every person knew the 
    law.” 498 U.S. at 199
    . That presumption might
    not always hold true anymore given the “proliferation of statutes and regulations,”
    especially in the tax context, so Congress has “softened” its impact “by making
    43
    specific intent to violate the law an element of certain federal criminal tax offenses.”
    
    Id. at 199–200
    (citing United States v. Murdock, 
    290 U.S. 389
    (1933)). Accordingly,
    Cheek recognized that since the 1930’s, the Court has interpreted the term “willfully”
    in federal criminal tax statutes “as carving out an exception to the traditional rule.”
    
    Id. at 2
    00. “Willfulness,” Cheek explained, means “the ‘voluntary, intentional
    violation of a known legal duty.’” 
    Id. at 2
    01 (quoting United States v. Pomponio, 
    429 U.S. 10
    , 12 (1976)). Cheek, however, didn’t suggest that the general mistake-of-law
    rule disappears whenever an offense may be categorized as malum prohibitum.
    Moreover, Congress didn’t put a “willfulness” requirement in the NFA. See 26
    U.S.C. § 5861. As explained above, the NFA is silent about mens rea. The Court
    filled the gap, based on the presumption that criminal liability should attach only
    when a defendant knows the facts that make his conduct illegal, by requiring that the
    defendant know the characteristics of a firearm that bring it within the NFA’s ambit.
    
    Staples, 511 U.S. at 619
    . The Court took the mens-rea presumption no further,
    however, “lest it conflict with the related presumption, ‘deeply rooted in the
    American legal system,’ that, ordinarily, ‘ignorance of the law or a mistake of law is
    no defense to criminal prosecution.’” 
    Id. at 622
    n.3 (Ginsburg, J., concurring)
    (quoting 
    Cheek, 498 U.S. at 199
    ). Under Staples, then, certain factual mistakes (e.g.,
    that a firearm isn’t a “firearm” for NFA purposes) may provide a defense to a charge
    of violating the NFA, but legal mistakes (e.g., that the NFA doesn’t apply to locally
    made firearms) do not.
    44
    Accordingly, we reject Kettler’s argument that the mens rea element of 26
    U.S.C. § 5861 should be subject to a mistake-of-law defense like the Model Penal
    Code’s.
    *      *      *
    Finally, we note that Cox’s and Kettler’s reliance on the SAPA did, in the end,
    mitigate their sentences, if not their guilt. At the sentencing hearing, the court
    reasoned that even though the SAPA wasn’t available as a defense at trial, the court
    could “take [it] into account” in deciding to impose probationary, instead of prison,
    sentences. Cox R. vol. 3 at 716:14–15. Speaking to Cox and Kettler, the court said, “I
    believe that you both honestly felt that you were protected by [the SAPA] and I
    believe that to be so[.]” 
    Id. at 716:15–17.
    Thus, the court continued, “I am giving you
    what benefit I can of that statute here at sentencing.” 
    Id. at 717:12–13.
    That benefit
    turned out to be two years’ probation for Kettler and one year’s for Cox. (The NFA
    allows for a penalty of up to ten years in prison, a fine of up to $10,000, or both for
    violating any of its provisions. 26 U.S.C. § 5871.)
    For all these reasons, we conclude that the district court was correct to prohibit
    Cox and Kettler from introducing their reliance on the SAPA as a defense to their
    NFA charges. Cox and Kettler received a fair trial and, at sentencing, the benefit of
    their good-faith reliance on the SAPA, so we see no reason—be it grounded in
    notions of due process or premised on presumptions about mens rea—either to create
    a new defense out of whole cloth (as Cox suggests) or to borrow one from the Model
    Penal Code (as Kettler suggests).
    45
    2. Was Kettler “Snared in a Constitutional Dispute Between Two
    Independent but Interrelated Civil Sovereigns”?
    In a related argument, Kettler contends that the political rumpus following the
    SAPA’s enactment “snared [him] in a constitutional dispute between two
    independent but interrelated civil sovereigns.” Kettler’s Opening Br. at 36. Citing the
    Declaration of Independence and its protection of unalienable rights, he argues that
    “[w]henever any government becomes destructive of those rights, it is the duty of the
    people—through their lower civil magistrates—to resist the misuse of power even to
    the point of taking up arms against tyranny as America’s founders did in 1776.” 
    Id. at 44–45
    (footnote omitted). Contrary to the founders’ federalist ideals, Kettler claims
    that after passing the SAPA, Kansas’s resolve weakened. “In a deferential, not
    confrontational, letter,” he notes, the Kansas Attorney General asked the U.S.
    Attorney General either to order the dismissal of the indictment or to support a
    presidential pardon. 
    Id. at 46.
    But Kettler claims that he deserves more than clemency
    or a pardon—“[h]e deserves the protection of the republican form of government
    established in Kansas at the time of its admission to the union so that he is not
    punished for being caught between the two sovereigns to which he oversees
    allegiance.” 
    Id. at 47.
    We’re unable to give Kettler either as an appellate remedy. The Constitution
    created the “judicial Power” to resolve cases and controversies, U.S. Const. art. III,
    § 2, cl. 1, and to do so, we have jurisdiction “of appeals from all final decisions of the
    district courts,” 28 U.S.C. § 1291. As Chief Justice Marshall wrote, “the essential
    46
    criterion of appellate jurisdiction” is “that it revises and corrects the proceedings in a
    cause already instituted, and does not create that cause.” Marbury v. Madison, 5 U.S.
    (1 Cranch) 137, 175 (1803). Yet in making his argument, Kettler points to no error in
    the district-court proceedings. Without such a claim, we can’t simply order the
    executive branch to grant Kettler clemency or demand that Kansas grant him the
    protection of a republican form of government. Stated otherwise, to fulfill the
    judiciary’s duty “to say what the law is,” we need a legal question. 
    Id. at 177.
    Accordingly, we decline to grant Kettler relief for being “snared in a
    constitutional dispute” between Kansas and the federal government. Kettler’s
    Opening Br. at 36.
    CONCLUSION
    For these reasons, we affirm the judgments of the district court.
    47
    17-3034, United States v. Cox
    17-3035, United States v. Kettler
    HARTZ, Circuit Judge, concurrence
    I join Judge Phillips’s opinion in full. I add this comment solely to caution against
    overreading our holding regarding silencers. In determining that silencers are not
    protected by the Second Amendment, we explain that they are not “bearable arms.” We
    had no occasion to consider whether items that are not themselves bearable arms but are
    necessary to the operation of a firearm (think ammunition) are also protected.
    

Document Info

Docket Number: 17-3034

Citation Numbers: 906 F.3d 1170

Filed Date: 10/16/2018

Precedential Status: Precedential

Modified Date: 1/12/2023

Authorities (45)

United States v. Dorris , 236 F.3d 582 ( 2000 )

United States v. John Val Browning , 630 F.2d 694 ( 1980 )

United States v. William Louis McCollom , 12 F.3d 968 ( 1993 )

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United States v. Ricky Vernon Nichols , 21 F.3d 1016 ( 1994 )

United States v. Hector Hernandez-Urista , 9 F.3d 82 ( 1993 )

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United States v. Marzzarella , 614 F.3d 85 ( 2010 )

United States v. Hardridge , 379 F.3d 1188 ( 2004 )

United States v. John William Dalton , 960 F.2d 121 ( 1992 )

United States v. Reese , 627 F.3d 792 ( 2010 )

United States v. Gutierrez-Gonzalez , 184 F.3d 1160 ( 1999 )

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United States v. Skoien , 614 F.3d 638 ( 2010 )

United States v. Eric Lamont Aiken , 974 F.2d 446 ( 1992 )

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