Bondi v. Vanderstok, 604 U.S. ___ (2025)

SUPREME COURT OF THE UNITED STATES

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No. 23–852

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PAMELA BONDI, ATTORNEY GENERAL, et al., PETITIONERS v. JENNIFER VANDERSTOK, et al.

on writ of certiorari to the united states court of appeals for the fifth circuit

[March 26, 2025]

Justice Sotomayor, concurring.

I join the Court’s opinion in full. I write separately to address two points raised in the writings that follow. The first is a concern that ATF’s rule might leave regulated entities in doubt about when and how to comply with the Gun Control Act. See post, at 1 (Kavanaugh, J., concurring). That worry is unfounded.

For more than half a century, firearms dealers, manufacturers, and importers have complied with the Gun Control Act’s requirements. They have marked their products with serial numbers, kept records of firearm sales, and conducted background checks for prospective buyers. See 18 U. S. C. §§922(t), 923(g)(1)(A), 923(i). These requirements are not new to the industry, and covered entities know they must maintain familiarity with the statute and accompanying regulations to run their businesses. In fact, the Act requires such entities to obtain federal licenses before selling, manufacturing, or importing any firearms in the first place. §923(a).

What is new is that some manufacturers have sought to circumvent the Act’s requirements by selling easy-to- assemble firearm kits and frames, which they claim fall outside the statute’s scope. See 87 Fed. Reg. 24652, 24655, 24686 (2022). ATF’s rule simply confirms what was already clear: The Gun Control Act does not tolerate such evasion. Its plain text covers firearm kits and unfinished frames or receivers designed for ready conversion, as the Court explains. So, for entities who seek to comply with the Act in good faith, ATF’s rule should come as no surprise. Nor should it create any difficulty discerning how to abide by the law.

To the extent any manufacturer has doubts about whether a particular product qualifies as a covered firearm, moreover, it can eliminate uncertainty by seeking clarification from the agency. ATF encourages manufacturers to submit potentially covered products to the agency for classification decisions. See Brief for Petitioners 5 (citing Dept. of Justice, Bureau of ATF, Office of Enforcement Programs & Servs., ATF National Firearms Act Handbook 41 (ATF E-Publication 5320.8 rev. Apr. 2009)); 27 CFR §478.92(c) (2023). Manufacturers have long taken advantage of that process, see, e.g., App. 8, 10–12, 21–22, 50–52, 53–54, and a failure to do so might suggest willfulness on their part.The second point I address is the suggestion that the Act permits ATF to regulate only “all-but-assembled” weapon parts kits and frames “as close to completion as possible.” Post, at 1 (Alito, J., dissenting). The Court’s opinion speaks for itself on that point and others. I encourage readers to go to the source, rather than rely on dissents, to understand what the Court holds. See ante, at 7, 11–12, 18, 20–22, 24. It is the Court’s ruling, not the one set forth by the dissents, that binds the lower courts.

SUPREME COURT OF THE UNITED STATES

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No. 23–852

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PAMELA BONDI, ATTORNEY GENERAL, et al., PETITIONERS v. JENNIFER VANDERSTOK, et al.

on writ of certiorari to the united states court of appeals for the fifth circuit

[March 26, 2025]

Justice Kavanaugh, concurring.

I join the Court’s opinion in full. I add this concurrence to briefly address mens rea issues with respect to ATF’s 2022 rule.

Under ATF’s rule, an individual or business acting in good faith might nonetheless have substantial difficulty determining when weapon parts kits or unfinished frames or receivers qualify as firearms—and thereby become subject to the Gun Control Act’s licensing, recordkeeping, serialization, and background-check requirements. Some weapon parts kits and unfinished frames or receivers may qualify as firearms, and others may not. See ante, at 13, 21. The line is not entirely clear. Despite the vagueness of the line, the penalties for violations are significant and can include fines and imprisonment. See 18 U. S. C. §924.

But importantly, under the Gun Control Act, someone can be penalized for violating the licensing, recordkeeping, or serialization requirements only if he does so “willfully.” §924(a)(1)(D). To prove “willfulness,” the Government must demonstrate that an individual knew that his conduct was unlawful, not merely that he knew the facts that made his conduct unlawful. Bryan v. United States, 524 U.S. 184, 191–196 (1998). Therefore, with respect to ATF’s rule, the “willfulness” requirement should help prevent the Government from unfairly penalizing an individual who is not aware that his conduct violates the law.

As to background-check violations, by contrast, the statute penalizes violations committed “knowingly.” §§922(t), 924(a)(5). The “knowingly” mens rea requires “proof of knowledge of the facts that constitute the offense.” Id., at 193. Unlike the “willfully” mens rea, it generally does not require knowledge that the conduct was unlawful. See id., at 192–193. That lesser “knowingly” mens rea requirement could therefore create concerns about fair notice, at least in certain cases. See Wooden v. United States, 595 U.S. 360, 379 (2022) (Kavanaugh, J., concurring).

That said, at oral argument, the Government represented that it would “likely” decline to “charge someone” for a background-check violation in the “kind of situation” where the individual was not aware that he was violating the law. Tr. of Oral Arg. 46–47. As the Government seemed to recognize, if the Government were to charge a background-check violation against an individual who was unaware that he was violating the law, that defendant might have a due process argument based on lack of fair notice. I expect that the Government will seek to avoid that potential fair-notice problem by adhering to its oral-argument representation that it would likely decline to bring charges in those circumstances.

SUPREME COURT OF THE UNITED STATES

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No. 23–852

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PAMELA BONDI, ATTORNEY GENERAL, et al., PETITIONERS v. JENNIFER VANDERSTOK, et al.

on writ of certiorari to the united states court of appeals for the fifth circuit

[March 26, 2025]

Justice Jackson, concurring.

To me, the nature of the claim at issue in this case makes its resolution quite straightforward. No one disputes that Congress delegated rulemaking authority to the Executive Branch through the Gun Control Act of 1968, as amended. See 18 U. S. C. §926(a). Nor is it contested that the Bureau of Alcohol, Tobacco, Firearms and Explosives, an Executive Branch agency, relied on that delegated authority to promulgate the challenged rule. Before us, respondents claim only that portions of the resulting rule exceed the agency’s statutory authority. See 5 U. S. C. §706(2)(C). Our judicial charge, then, is to evaluate the scope of the Gun Control Act’s delegation of authority to the agency, and to determine whether the agency’s actions transgressed those bounds. That limited exercise should be dispositive.

Proper excess-of-authority review must focus on actual statutory boundaries, not on whether the agency’s discretionary choices overlap precisely with what we, as unelected judges, would have done if we were standing in the agency’s shoes. And where, as here, the statute’s boundaries do not foreclose the agency’s action, the excess-of-authority claim should meet its end. I concur because I read the Court’s opinion to be consistent with this view.

SUPREME COURT OF THE UNITED STATES

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No. 23–852

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PAMELA BONDI, ATTORNEY GENERAL, et al., PETITIONERS v. JENNIFER VANDERSTOK, et al.

on writ of certiorari to the united states court of appeals for the fifth circuit

[March 26, 2025]

Justice Thomas, dissenting.

The Government asked this Court just last Term to “ ‘rewrite’ ” statutory text so that it could regulate semiautomatic weapons as machineguns. Garland v. Cargill, 602 U.S. 406, 428 (2024). We declined to do so. The Government now asks us to rewrite statutory text so that it can regulate weapon-parts kits. This time, the Court obliges. I would not. The statutory terms “frame” and “receiver” do not cover the unfinished frames and receivers contained in weapon-parts kits, and weapon-parts kits themselves do not meet the statutory definition of “firearm.” That should end the case. The majority instead blesses the Government’s overreach based on a series of errors regarding both the standard of review and the interpretation of the statute. I respectfully dissent.

I

A

In 1934, Congress enacted the National Firearms Act (NFA), the first federal statute to regulate the firearms industry. Congress enacted this statute to “provide for the taxation of manufacturers, importers, and dealers in certain firearms and machine guns, to tax the sale or other disposal of such weapons, and to restrict importation and regulate interstate transportation thereof.” Ch. 757, 48 Stat. 1236.

The NFA defined “firearm” narrowly. The term covered only certain short-barreled shotguns or rifles, machineguns, and silencers or mufflers. Ibid. Congress broadened that definition four years later through the Federal Firearms Act of 1938 (FFA), defining “firearm” to include “any weapon . . . designed to expel a projectile or projectiles by the action of an explosive . . . or any part or parts of such weapon.” 52Stat. 1250 (emphasis added). With minor amendments not relevant here, that definition endured for about 30 years.

In 1968, Congress replaced the FFA with the Gun Control Act (GCA). The GCA, which remains in effect today, is the principal federal law regulating the commercial firearm market. See Pub. L. 90–618, 82Stat. 1213. It requires manufacturers and dealers of firearms to have a federal license, and, in most cases, to conduct background checks, maintain records, and apply serial numbers to their firearms. See 18 U. S. C. §§922(t) and 923(a), (g)(1)(A), and (i). The GCA also imposes criminal sanctions for a variety of well-known firearms offenses. See, e.g., §922(g) (prohibiting large swaths of people from shipping, transporting, possessing, or receiving a “firearm”); §924(c) (providing a sentencing enhancement for persons who carry a “firearm” during crimes of violence or drug-trafficking crimes).

The GCA sets forth a narrower definition of “firearm” than the FFA did. Its definition, which governs all of “Chapter 44—Firearms,” §§921–934, states that a “firearm” is:

“(A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive; (B) the frame or receiver of any such weapon; (C) any firearm muffler or firearm silencer; or (D) any destructive device. Such term does not include an antique firearm.” §921(a)(3).

Whereas the FFA had treated “any part or parts” of a firearm as a regulable firearm, the GCA deems only a firearm’s “frame or receiver” to be firearm parts that qualify as a firearm in their own right. §921(a)(3)(B).

Congress left the terms “frame” and “receiver” undefined. See §921. Shortly after the GCA’s enactment, the Bureau of Alcohol and Tobacco Tax Division[1] promulgated a regulation defining “frame or receiver” as “[t]hat part of a firearm which provides housing for the hammer, bolt or breechblock, and firing mechanism, and which is usually threaded at its forward portion to receive the barrel.” 33 Fed. Reg. 18558 (1968) (emphasis deleted).[2]

That regulatory definition made sense. At the time of the GCA’s enactment, the term “frame” was generally understood to mean “the basic structure and principal component of a firearm.” C. Mueller & J. Olson, Small Arms Lexicon and Concise Encyclopedia 87 (1968) (Olson’s). And, the term “receiver” was generally understood to mean the “part of a gun that houses the breech action and firing mechanism.” Id., at 168. Thus, ATF’s initial definition of “frame or receiver” accorded with the terms’ ordinary meanings. See 33 Fed. Reg. 18558 (“[t]hat part of a firearm which provides housing for the hammer, bolt or breechblock, and firing mechanism”).

ATF ’s definition also aligned with the GCA, because for “any weapon” to “expel a projectile by the action of an explosive,” §921(a)(3)(A), the weapon must have both a mechanism that will initiate that explosion and a way to seal the firing chamber. In other words, the weapon must have a “frame” or “receiver.” See Olson’s 87, 168. Thus, by defining frame or receiver as the parts of a gun that provide “housing for the hammer, bolt or breechblock, and firing mechanism,” 33 Fed. Reg. 18558, ATF’s initial definition fit neatly into the statutory scheme. This understanding of “frame” and “receiver” governed for over 50 years.

But, ATF recently changed course, in an effort to regulate so-called ghost guns—i.e., privately made firearms built from kits or collections of unfinished parts. To tackle what it perceived to be the “homeland security threat” posed by the “wide availability of ghost guns,” the agency promulgated a rule redefining “firearm,” “frame,” and “receiver.” Definition of “Frame or Receiver” and Identification of Firearms, 87 Fed. Reg. 24652, 24658 (2022) (Rule) (internal quotation marks omitted). Without any change to the statute, this Rule expanded the regulatory definition of “firearm” to include “a weapon parts kit that is designed to or may readily be completed, assembled, restored, or otherwise converted to expel a projectile by the action of an explosive.” 27 CFR §478.11 (2023). It also broadened the definition of “frame or receiver” to include “a partially complete, disassembled, or nonfunctional frame or receiver, including a frame or receiver parts kit, that is designed to or may readily be completed, assembled, restored, or otherwise converted to function as a frame or receiver.” §478.12(c).

One of the Rule’s critical innovations is the manner in which it allows ATF to determine whether an object is “clearly identifiable”—and thus regulable—as an unfinished frame or receiver:

“When issuing a classification, the Director may consider any associated templates, jigs, molds, equipment, tools, instructions, guides, or marketing materials that are sold, distributed, or possessed with the item or kit, or otherwise made available by the seller or distributor of the item or kit to the purchaser or recipient of the item or kit.” Ibid.

“Prior to this rule, ATF did not examine templates, jigs, or other items and materials in determining whether partially complete frames or receivers were ‘firearms’ under the GCA.” 87 Fed. Reg. 24668; see also Tr. of Oral Arg. 39–40 (acknowledging the change). Instead, ATF looked to the object itself to determine whether it was sufficiently complete to constitute a regulable frame or receiver. See, e.g., App. 23 (2004 guidance letter from ATF explaining that the agency “evaluates the level of completion of the submitted sample . . . and makes a comparison with a sample of a completed firearm of the same type”). The new definition, however, expanded the meaning of “frame” and “receiver” to incorporate items entirely separate from the object itself. According to ATF, whether an unusable, unfinished piece of metal constitutes a regulable “frame or receiver” can turn on a manufacturer’s “marketing materials.” 87 Fed. Reg. 24668.

ATF offered one meager limit on its broad, new definitions: Under the Rule, “raw material,” such as an “unformed block of metal” or “liquid polymer,” will not constitute a regulable frame or receiver. 27 CFR §478.12(c).

B

Before the Rule took effect, a group of individuals and manufacturers of weapon-parts kits filed a petition for review challenging the Rule’s new definitions of “frame or receiver” and “firearm.” As relevant here, the plaintiffs alleged that the Rule exceeded ATF’s “statutory jurisdiction, authority, or limitations” under the Administrative Procedure Act (APA), 5 U. S. C. §706(2)(C). See Amended Petition for Judicial Review of Agency Action and Request for Declaratory Judgment and Injunctive Relief in No. 4:22–cv–691 (ND Tex., Oct. 5, 2022), ECF Doc. 93, p. 42 (alleging Rule’s expansive definitions provided ATF “new, additional authority in excess of that proposed, considered, debated, or passed by Congress”).

The District Court granted summary judgment to the plaintiffs and vacated the Rule. 680 F. Supp. 3d 741 (ND Tex. 2023). The Fifth Circuit affirmed in relevant part. 86 F. 4th 179 (2023). It held that ATF’s redefinition of “frame or receiver” was an “impermissible extension of the statutory text,” id., at 189, and that the agency’s attempt to redefine “firearm” to include a weapon-parts kit “stretche[d] the [statute’s] words too far,” id., at 192. The Government’s effort “to justify its unprecedented expansion of the GCA,” the court explained, “collapses upon a cursory reading of the text.” Id., at 193.

Judge Oldham wrote separately to highlight the “staggering” implications of ATF’s new position, particularly with respect to the AR–15, “the most popular rifle in America.” Id., at 208 (concurring opinion). Observing that the Rule regulates frames and receivers according to what they might become rather than what they are, and that an AR–15’s semiautomatic receiver can “ ‘readily be converted’ ” into a fully automatic receiver with relative ease, he concluded that, on ATF’s logic, the Government may regulate AR–15s as machineguns. Id., at 207–208. If ATF were correct, Judge Oldham cautioned, “then millions and millions of Americans would be felons-in-waiting.” Id., at 208.

This Court granted certiorari to decide two questions: whether the Rule’s new definition for frames and receivers fits within the statutory definition of “frame or receiver” under the GCA, see §921(a)(3)(B); and whether the statutory term “firearm” can cover weapon-parts kits.

II

Before turning to the questions presented, a threshold issue is the applicable legal standard for analyzing the plaintiffs’ APA challenge. Applying traditional principles of statutory interpretation, the Fifth Circuit asked whether the Rule “conflicts with the plain language of the GCA” or “cast[s] a wider net than Congress intended.” 86 F. 4th, at 190, 194. We took this case to determine whether the Fifth Circuit was correct to answer “yes.” I would undertake the same inquiry as the Fifth Circuit and ask only whether the Rule contravenes “clear statutory text” or otherwise “exceeds the [GCA’s] legislatively-imposed limits on agency authority.” Id., at 182.

The majority takes a different approach. Asserting that the plaintiffs conceded to having brought a “ ‘facial’ ” challenge, the Court “take[s]” this characterization “as given,” and analyzes the challenge as a facial attack.[3] Ante, at 7. In particular, the Court assumes, arguendo, that the regulatory definitions are valid so long as they cover “at least some weapon parts kits.” Ante, at 13. This approach superficially appears to apply a framework similar to that of United States v. Salerno, 481 U.S. 739 (1987). There, the Court explained that, to prevail in a “facial challenge” to a statute, the challenger must establish that “no set of circumstances exists under which the Act would be valid.” Id., at 745.

This approach seems plainly inapt in a challenge to a regulatory definition. “To ‘define’ is . . . ‘to settle’ or ‘to establish or prescribe authoritatively.’ ” Puerto Rico v. Franklin Cal. Tax-Free Trust, 579 U.S. 115, 126 (2016) (quoting Black’s Law Dictionary 380 (5th ed. 1979)); see also id., at 534 (12th ed. 2024) (equating “define” with “To state or explain explicitly”; “[t]o fix or establish (boundaries or limits)”; and “[t]o set forth the meaning of (a word or phrase)”). The point of defining a term in a regulation is therefore to show what the law permits and what it prohibits. But, a regulatory definition that is accurate in only a single valid application cannot possibly “explain explicitly,” “fix or establish,” or “set forth the meaning” of a statutory term. Id., at 534.

Consider a hypothetical statute that defines “motorcycle” as “a motor-powered, two-wheeled vehicle with pedals.” If a regulatory definition copied the same language, and then added that “the term shall include any motorized vehicle,” the regulatory definition obviously would be wrong. Not every motorized vehicle is a motorcycle, and the fact that some motorized vehicles happen to be motor-powered, two-wheeled vehicles with pedals does not suggest otherwise. It is difficult to see how an overbroad regulatory definition becomes defensible simply because some set of circumstances exists in which the regulatory definition overlaps with the statutory definition.[4]

Treating challenges to regulatory definitions as “facial challenges” has substantial implications. If a regulatory definition survives APA challenge so long as just one item it covers also happens to be covered by the statute it purports to interpret, it is difficult to understand how an agency would ever promulgate an invalid definition. So long as it imports the definition Congress laid out in the statute, the agency can sweep in whatever additional conduct it wishes. No matter how far the agency expands its regulatory definition, the statutory definition inevitably will capture at least some of it.

To its credit, the majority attempts to confine the effects of its approach to the facts of this case. Because the majority assumes the relevant legal standard without deciding it, it refrains from mandating this framework. Rather, it rests on its conclusion that the plaintiffs essentially conceded that the facial-challenge standard applies, and it takes the application of that standard “as given” for this case only. Ante, at 7; see ibid., n. 2 (“[W]e believe the better course is to leave further analysis of the proper test for another day and address the parties’ dispute as they have chosen to frame it”). So long as lower courts do not equate an APA challenge with a “facial” one, they are free to disregard the majority’s analysis and hold that the Rule exceeds ATF’s statutory authority.[5]

III

As for the questions presented, start with the question whether the Rule’s new definition for frames and receivers can stand. Ordinary principles of statutory interpretation make plain that the Rule sweeps too far: The terms “frame” and “receiver” in §921(a)(3)(B) do not cover “partially complete, disassembled, or nonfunctional frame[s] or receiver[s].” 27 CFR §478.12(c). The majority reaches a different conclusion based on several interpretive errors. Most notably, the majority proceeds under the faulty premise that our standard rules of statutory interpretation do not apply to “a word for a thing created by humans.” Ante, at 10.

A

“In statutory interpretation disputes, a court’s proper starting point lies in a careful examination of the ordinary meaning and structure of the law itself.” Food Marketing Institute v. Argus Leader Media, 588 U.S. 427, 436 (2019). As relevant here, §921(a)(3) defines “firearm” to include “(A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive,” and “(B) the frame or receiver of any such weapon.” Because the GCA defines neither “frame” nor “receiver,” “ ‘we give [each] term its ordinary meaning.’ ” Encino Motorcars, LLC v. Navarro, 584 U.S. 79, 85 (2018).

The parties agree that, in 1968, the terms “frame” and “receiver” were understood to refer to “ ‘the basic structure and principal component of a firearm,’ ” and “the ‘part of a gun that houses the breech action and firing mechanism.’ ” Brief for Petitioners 32 (quoting Olson’s 87, 168); Brief for Respondent VanDerStok et al. 7 (same). But, ATF’s Rule conflicts with this accepted meaning in at least two ways. First, it defines “frame or receiver” to include objects that are not frames or receivers, but that may be “converted” into them in the future. 27 CFR §478.12(c). Second, it permits ATF to deem an object a frame or receiver based on “marketing materials” and other materials merely associated with it. Ibid.

1

The ordinary meaning of “frame or receiver” does not include objects that may be “converted” into a frame or receiver. Ibid. As the Government itself admits, the word “ ‘convert’ ” means “ ‘[t]o change into another form, substance, state, or product; transform; transmute.’ ” Brief for Petitioners 19–20 (quoting American Heritage Dictionary 291 (1969)). If an object can become a frame or receiver only after it is “change[d] into another form, substance, state, or product,” it is difficult to understand how the object can be considered a frame or receiver even before the change occurs. Ibid. As the Fifth Circuit put it, “a part cannot be both not yet a receiver and a receiver at the same time.” 86 F. 4th, at 190 (internal quotation marks omitted).

The structure of §921(a)(3) confirms that objects that are not yet frames or receivers do not meet the statutory definition of “frame or receiver.” §921(a)(3)(B). Subsection (A) of §921(a)(3) covers weapons that are not yet functional guns but that “may readily be converted” into them. And, the statute makes clear that subsections (C) (mufflers and silencers) and (D) (destructive devices), also cover more than finished, operable products. See §921(a)(25) (defining “muffler” and “silencer” to include “any combination of parts . . . for use in assembling” such objects); §921(a)(4)(C) (defining “destructive device” to include any “combination of parts” for “converting any device into any destructive device” described in the statute and “from which a destructive device may be readily assembled”). In contrast, subsection (B) covers only a weapon’s “frame or receiver.”

“[W]hen Congress includes particular language in one section of a statute but omits it in another section of the same Act, it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or exclusion.” Barnhart v. Sigmon Coal Co., 534 U.S. 438, 452 (2002) (internal quotation marks omitted). This principle holds particular force here, where Congress applied broadening language to the subject matter of every subsection in §921(a)(3) except for subsection (B). Yet, in defining “frame” and “receiver” to include objects that “may readily be completed, assembled, restored, or otherwise converted to function as a frame or receiver,” 27 CFR §478.12(c), the Rule transplants the “readily be converted” and “assembled” concepts from subsections (A), (C), and (D) into subsection (B)—the very provision from which Congress omitted them.

The straightforward reading of §921(a)(3) is the correct one: Subsection (B)’s omission of the readily converted and readily assembled concepts means that a “frame or receiver” does not include objects that are not yet frames or receivers. And, until promulgating the Rule, ATF agreed with this understanding:

“Importantly, the ‘designed to’ and ‘readily be converted’ language are only present in the first clause of the statutory definition. Therefore, an unfinished frame or receiver does not meet the statutory definition of ‘firearm’ simply because it is ‘designed to’ or ‘can readily be converted into’ a frame or receiver. Instead, a device is a firearm either: (1) because it is a frame or receiver or; (2) it is a device that is designed to or can readily be converted into a device that ‘expel[s] a projectile by the action of an explosive.’ ” Memorandum of Law in Syracuse v. ATF, No. 1:20–cv–06885 (SDNY, Jan. 29, 2021), ECF Doc. 98, p. 14 (Brief for ATF) (citation omitted).

See also id., at 36–39 (explaining why “An Unmachined Frame or Receiver Cannot Be Readily Converted Into a Device that Expels a Projectile”). ATF was right the first time.

Tellingly, ATF’s new interpretation seems to invite “staggering” consequences. 86 F. 4th, at 208 (Oldham, J., concurring). The NFA defines “ ‘machinegun’ ” as “any weapon which shoots . . . automatically more than one shot, without manual reloading, by a single function of the trigger,” and “include[s]” in that definition “the frame or receiver of any such weapon.” 26 U. S. C. §5845(b). ATF has defined “frame or receiver” in the NFA to “have the same meaning as in §478.12”—the provision that defines those terms under the GCA. 27 CFR §479.11. And, although an unmodified AR–15 is a semiautomatic weapon, “every single AR–15 can be converted to a machinegun using cheap, flimsy pieces of metal—including coat hangers.” 86 F. 4th, at 208 (Oldham, J., concurring).

If an object already is what it may be converted into, 27 CFR §478.12(c), then semiautomatic AR–15s would seem to be partially complete, automatic machineguns. This reasoning exposes the manufacturers, sellers, and owners of AR–15s to criminal liability under the NFA. See 26 U. S. C. §§5861, 5871. But, Congress does not “hide elephants in mouseholes.” Whitman v. American Trucking Assns., Inc., 531 U.S. 457, 468 (2001). An interpretive approach that would allow ATF to regulate the most popular semiautomatic rifle in America under a statute addressing automatic machineguns should give us pause. Cf. Dubin v. United States, 599 U.S. 110, 130 (2023) (“Time and again, this Court has prudently avoided reading incongruous breadth into opaque language in criminal statutes”).

2

The Rule’s definitions of “frame” and “receiver” also contravene ordinary meaning by allowing ATF to classify objects as frames or receivers based on criteria other than the object’s physical characteristics. Under the Rule, any “tools, instructions, guides, or marketing materials” that are “made available by the seller” can convert an unregulated piece of metal into a regulated “frame or receiver.” 27 CFR §478.12(c). Put another way, the mere presence of things distinct from the object at issue can somehow transform the character of the object itself.

Figure 1. See Dept. of Justice, ATF, Open Letter to All Federal Firearms Licensees 3, 6 (Sept. 27, 2022), https:// www.atf.gov/firearms/docs/open-letter/all-ffls-september-2022- impact-final-rule-2021-05f-partially-complete-ar/download.

Figure 1, supra, illustrates the Rule in action. Both images in Figure 1 depict unfinished receivers. Both lack machining and indexing in the key areas. The only difference is the presence of a jig and drill bits. Yet, according to the Rule, these extraneous items make an unfinished receiver a regulable firearm.

The presence of items such as jigs or “marketing materials”—that are not, and never could be, part of a frame or receiver—has no bearing on whether a piece of metal or plastic constitutes “the basic structure and principal component of a firearm.” Olson’s 87. Because those extrinsic items have no impact on the ordinary meanings of “frame” or “receiver,” the regulatory definition exceeds statutory text by using such items to expand the scope of those statutory terms. Cf. Encino Motorcars, 584 U. S., at 85 (an undefined statutory term receives its ordinary meaning).

B

The majority leaves the issue of extrinsic objects for another day, deeming the issue irrelevant under its questionable facial-challenge standard. Ante, at 23. The majority thus defends only the Rule’s coverage of items that may become frames or receivers. To do so, it substitutes novel linguistic labels for traditional statutory interpretation; mistakes outlier definitions for exemplars; and improperly imports attributes of one provision into another.

1

The majority’s statutory analysis deviates dramatically from the “careful examination of the ordinary meaning and structure of the law itself ” that is typically at the core of this Court’s interpretive approach. Food Marketing Institute, 588 U. S., at 436. Drawing heavily from an amicus brief and an academic paper,[6] the majority asserts that “the terms ‘frame’ and ‘receiver’ in subsection (B) are artifact nouns,” ante, at 19—that is, they are words for “thing[s] created by humans,” ante, at 10. The majority argues that this type of noun is flexible enough to encompass unfinished objects. It explains that, in casual conversation, one might refer to an artifact noun such as an “unfinished manuscript” as a “novel,” or an unassembled piece of furniture from IKEA as a “table.” Ante, at 10–11. Thus, the majority argues, a “frame” or “receiver” “may sometimes describe not-yet-complete” frames or receivers. Ante, at 19.

It is beside the point whether, in casual conversation, some people might use “a word for a thing created by humans” to discuss unfinished versions of that “thing.” Ante, at 10. “In statutory drafting, where precision is both important and expected, the sort of colloquial usage on which the [majority] relies is not customary.” Allison Engine Co. v. United States ex rel. Sanders, 553 U.S. 662, 670 (2008). We have expressly “presumed” that Congress does not “draft its laws” with the informality of “casual conversation.” Arcadia v. Ohio Power Co., 498 U.S. 73, 79 (1990).

Thus, we must evaluate the Rule’s redefinition of “frame” and “receiver” based on the GCA’s “entire statutory scheme,” Winkelman v. Parma City School Dist., 550 U.S. 516, 523 (2007), not the “ ‘stereotypical’ conversational background” on which the majority relies, Grimm 58. That scheme—as reflected in the GCA’s text, context, and structure—confirms that unfinished objects in a weapon-parts kit do not meet §921(a)(3)(B)’s terms. Supra, at 10–15. Dressing up colloquial usage with the “artifact noun” label cannot override this conclusion.[7]

2

The majority further argues that, because “§923(i) uses the phrase ‘frame or receiver’ to reach some unfinished and unconventional frames and receivers,” such as the “frame” or “receiver” of a muffler or silencer, it is reasonable to interpret §921(a)(3)(B) to also cover unusual frames or receivers. Ante, at 18–20. The majority’s conclusion does not follow its premise.

Section 921(a)(3)(C) defines a firearm to include “any firearm muffler or silencer.” Section 923(i) requires licensed importers and manufacturers to place a serial number on a firearm’s “receiver or frame.” To reconcile §921(a)(3)(C) with §923(i)’s requirement, mufflers and silencers must have a “receiver or frame” even though they do not as a matter of ordinary meaning. Thus, by regulation, ATF deems a muffler’s or silencer’s “outer tube or modular piece” to be its “frame or receiver.” 27 CFR §478.12(b).

In the context of mufflers and silencers, the terms “frame” and “receiver” have context-specific meanings that cannot be generalized to other provisions in Chapter 44. As ATF explained, “[u]nder the GCA, licensed manufacturers and importers must identify the frame or receiver of each firearm, including a firearm muffler or silencer, with a serial number in accordance with regulations.” 87 Fed. Reg. 24660. Calling an “outer tube or modular piece” of a muffler or silencer a “frame or receiver” thus may be justified as an attempt to square §923(i) with Congress’s decision to include mufflers and silencers within the definition of “firearm” under §921(a)(3)(C). Cf. A. Scalia & B. Garner, Reading Law: The Interpretation of Legal Texts 228 (2012) (Scalia & Garner) (explaining that context may, in rare circumstances, justify overriding a term’s established meaning). But, the presumption of consistent usage is “particularly defeasible by context,” see id., at 171, and there is no reason to think that the agency’s workaround for applying §923(i) to mufflers and silencers should alter the ordinary meanings of “frame” and “receiver” in other statutory provisions that do not implicate the same problem. In this case, the statutory scheme makes clear that §921(a)(3)(B)’s “frame or receiver” language does not include unfinished, inoperable objects even if one day they may become frames or receivers. Supra, at 11–15.

3

The majority further asserts that “reading subsection (B) in light of subsection (A)” actually “undermine[s]” the plaintiffs’ position. Ante, at 22. Again, subsection (A) covers any weapon which “may readily be converted” into a functional gun. §921(a)(3)(A). Subsection (B) specifies that a firearm includes the “ ‘frame or receiver of any such weapon.’ ” Ante, at 22 (emphasis added by majority). According to the majority, that reference in subsection (B) implicitly incorporates subsection (A)’s readily converted language. And, because subsection (A) covers “starter guns and disassembled rifles” that are “not yet fit for effective use in combat,” ibid., the majority argues that subsection (B) should also cover objects that are not yet usable. That conclusion does not follow.

The frames and receivers referred to in subsection (B) are components of the “weapon[s]” referred to in subsection (A). While the majority is correct that subsection (A)’s readily converted language covers weapons “not yet fit for effective use in combat,” ibid., there is no reason to think that the readily converted language in subsection (A) applies to the component parts described in subsection (B)—and every reason to think they do not. ATF recognized as much just a few years ago, explaining that “the ‘designed to’ and ‘readily be converted’ language are only present in the first clause of the statutory definition. Therefore, an unfinished frame or receiver does not meet the statutory definition of ‘firearm’ simply because it is ‘designed to’ or ‘can readily be converted into’ a frame or receiver.” Brief for ATF 14 (citation omitted). The majority’s examples of “starter guns and disassembled rifles,” ante, at 22, underscore the point that an inoperable weapon does not imply an inoperable frame or receiver: While neither type of weapon is “fit for effective use in combat,” ibid., their frames and receivers are typically operable.

“We do not lightly assume that Congress has omitted from its adopted text requirements that it nonetheless intends to apply, and our reluctance is even greater when Congress has shown elsewhere in the same statute that it knows how to make such a requirement manifest.” Jama v. Immigration and Customs Enforcement, 543 U.S. 335, 341 (2005). Rather than import language from one provision (subsection (A)) into another that conspicuously omits that language (subsection (B)), the Court should acknowledge that, naturally read, subsection (B) is not broadened by language omitted from it but included in the more expansive text of subsection (A).

IV

The Court also granted certiorari to decide whether a “firearm” can “include a weapon parts kit.” 27 CFR §478.11. Statutory text, context, and structure confirm that this aspect of the Rule also exceeds the scope of the statute. The majority’s novel artifact-noun methodology cannot alter this conclusion.

A

Section 921(a)(3)(A)’s definition of “firearm” includes “any weapon” that “will or is designed to or may readily be converted to expel a projectile by the action of an explosive.” Thus, while an object that “may readily be converted” into a gun qualifies as a “firearm” if that object is already a “weapon,” an object that is not already a weapon does not.

The ordinary meaning of “weapon” does not include weapon-parts kits. At the time of the GCA’s enactment, the word “weapon” was understood to mean “an instrument of offensive or defensive combat . . . something to fight with . . . something (as a club, sword, gun, or grenade) used in destroying, defeating, or physically injuring an enemy.” Webster’s Third New International Dictionary 2589 (1966) (Webster’s); accord, ante, at 10. A weapon-parts kit is not a weapon until it is converted into an operable gun. It is no more “something to fight with,” Webster’s 2589, than the sort of “unformed block of metal” that the Rule expressly exempts from regulation, see 27 CFR §478.12(c). The operable gun pictured in the majority opinion is “an instrument” one may use in “combat.” The unfinished, inoperable kit pieces are not. See ante, at 9 (images). Because these pieces do not constitute a “weapon,” they do not fit within subsection (A)’s statutory definition.

Statutory text and context reinforce this conclusion, as they indicate that the “weapon” contemplated in subsection (A) must have a “frame or receiver”—precisely the parts of a weapon that weapon-parts kits omit. Section 923, for example, requires manufacturers to identify their firearms “by means of a serial number engraved or cast on the receiver or frame of the weapon,” §923(i) (emphasis added), clearly implying that any such “weapon” includes a “receiver or frame.” Section 921 supports this reading by delimiting the definition of a “firearm” to “any weapon” convertible into a functional gun, and “the frame or receiver of any such weapon,” §§921(a)(3)(A)–(B) (emphasis added). This provision again assumes that the “weapon” in subsection (A) has a “frame or receiver.”

That “starter guns and disassembled rifles” are prototypical illustrations of things covered under §921(a)(3)(A) that nevertheless “are not yet fit for effective use in combat,” ante, at 22, underscores this conclusion. Both starter guns and disassembled rifles usually have functional frames or receivers. In contrast, the frames and receivers included in weapon-parts kits are unfinished, inoperable, and so cannot constitute frames or receivers under subsection (B). See supra, at 10–15. Since “any weapon” must have an operable “frame or receiver,” §921(a)(3)(B), a weapon-parts kit cannot be a “weapon.” Accordingly, it cannot become a regulated “firearm” under §921(a)(3)(A).[8]

Further, although the FFA previously regulated “any part or parts” of a gun, 52Stat. 1250, Congress limited the GCA’s coverage to only two such parts: “the frame or receiver,” §921(a)(3)(B). “Presumably, Congress singled out these components for special treatment because of the special role they play in constructing firearms.” Ante, at 4. We should “presume that a legislature says in a statute what it means and means in a statute what it says there.” Connecticut Nat. Bank v. Germain, 503 U.S. 249, 253–254 (1992).

The statute’s broader context also suggests that weapon-parts kits are not regulable “firearms.” Section 921(a)(3) defines “firearm” for all of Chapter 44. It follows that, “if [Chapter 44] is to be interpreted as a symmetrical and coherent regulatory scheme,” Gustafson v. Alloyd Co., 513 U.S. 561, 569 (1995), the term should to the extent possible receive a consistent meaning. While it is not difficult to envision how weapons that can be immediately assembled might be helpful “during and in relation to any crime of violence” under §924(c)—also part of Chapter 44—it is hard to imagine how an unfinished weapon-parts kit requiring conversion could be helpful. At minimum, this understanding would seem to imply a crime “during” which the criminal could take some untold amount of time to convert his kit into a functional gun before using it. That does not fit any crime of violence with which I am familiar. Cf. Babbitt v. Sweet Home Chapter, Committee for Great Ore., 515 U.S. 687, 722–723 (1995) (Scalia, J., dissenting) (“[T]he Secretary’s interpretation of ‘harm’ is wrong if it does not fit with the use of ‘take’ throughout the Act. And it does not”).[9]

B

Holding otherwise, the majority reasons that, as a “thing created by humans,” the term “weapon” may encompass not only weapons that are “combat ready,” but also those that are “disassembled,” and that the term thus captures weapon-parts kits “[i]n the same way and for the same reason.” Ante, at 10–11. The majority again conjures up the “artifact noun” to support an interpretation that is incompatible with our traditional methods of statutory construction. See supra, at 19–22.

Unlike a disassembled firearm, a weapon-parts kit requires more than merely assembling the parts to become a functional gun. Special tools and an indeterminate amount of time are required to convert an unfinished weapon-parts kit into a functional weapon. Thus, even assuming that the ordinary meaning of “weapon” does not resolve whether the term includes weapon-parts kits, at minimum the term “weapon” cannot encompass weapon-parts kits in “the same way” it covers disassembled firearms. Ante, at 11.

The majority also insists that the term “weapon” should cover “some unfinished instruments of combat” like weapon-parts kits because §921(a)(3)(A) includes starter guns, which, like weapon-parts kits, can be converted into functional weapons. Ante, at 11. But, because a starter gun does not fit within the ordinary meaning of “weapon,” Congress’s decision to expand that term to cover that one, specific object does not imply that Congress intended the word “weapon” to also cover other objects that are not already weapons. See n. 8, supra.

And, both a disassembled rifle and a starter gun are “weapons” for the reason a weapon-parts kit is not: Disassembled rifles and starter guns typically have functional frames or receivers. See supra, at 21.[10]

V

The text, context, and structure of §921(a)(3) leave little doubt that weapon-parts kits are not “firearms,” and that the unfinished contents of these kits are neither “frame[s]” nor “receiver[s].” But, even if it were reasonable to treat artifact nouns differently, the Government would—at most—demonstrate statutory ambiguity. And, when a statute with criminal applications is ambiguous, the rule of lenity applies. See Leocal v. Ashcroft, 543 U.S. 1, 12, n. 8 (2004).

This case is similar to United States v. Thompson/Center Arms Co., 504 U.S. 505 (1992). There, a majority of the Court applied the rule of lenity to interpret a tax statute with criminal applications. That case presented the question whether a gun manufacturer “makes” short-barreled rifles—and is thus subject to the NFA’s “making tax,” see 26 U. S. C. §5821—by selling a pistol and conversion kit from which one could make a short-barreled rifle. See 504 U. S., at 507 (plurality opinion). After considering several arguments—including analogies to products that “requir[e] some home assembly,” and comparisons to terms referring to “ ‘any combination of parts’ ”—the plurality concluded that it was “left with an ambiguous statute.” Id., at 509–517. And, because the provision carried the threat of criminal sanction, the plurality held that it was “proper . . . to apply the rule of lenity and resolve the ambiguity in Thompson/Center’s favor.” Id., at 518.

Justice Scalia concurred in the judgment. Whereas the plurality found ambiguity in the conversion kits’ potential uses, he attributed the ambiguity to a “much more fundamental” question: “[W]hether the making of a regulated firearm includes the manufacture, without assembly, of component parts where the definition of the particular firearm does not so indicate.” Id., at 519. He found persuasive the contrast between the definition of regulated objects that expressly included “any combination of parts,” and those that did not. See id., at 519–520 (noting that the provision at issue “conspicuously combine[s] references to ‘combination of parts’ in the definitions of regulated silencers, machineguns, and destructive devices with the absence of any such reference in the definition of regulated rifles”). Because neither the definition of “rifle” nor that of “short- barreled rifle” incorporated combinations of parts, these distinctions made clear that the NFA “d[id] not encompass Thompson/Center’s pistol and conversion kit, or at least d[id] not do so unambiguously.” Ibid.

I would take Justice Scalia’s approach here. Nothing in the GCA suggests that the terms “frame” and “receiver” also include the materials that one could use to create them, or that parts including neither a frame nor a receiver could constitute a “weapon.” See 18 U. S. C. §§921(a)(3)(A)–(B). There are, however, many reasons to conclude the opposite. See supra, at 10–23; cf. Thompson/Center, 504 U. S., at 519–520 (opinion of Scalia, J.).

Even the Government appears to have found these competing interpretations persuasive just a few years ago. See Brief for ATF 14, 36–39 (endorsing the position it now rejects). “Now it says the opposite. The law hasn’t changed, only an agency’s interpretation of it.” Guedes v. ATF, 589 U. S. ___, ___ (2020) (statement of Gorsuch, J., respecting denial of certiorari) (slip op., at 3). I would apply the rule of lenity here.

*  *  *

Congress could have authorized ATF to regulate any part of a firearm or any object readily convertible into one. But, it did not. I would adhere to the words Congress enacted. Employing its novel “artifact noun” methodology, the majority charts a different course that invites unforeseeable consequences and offers no limiting principle. I respectfully dissent.

SUPREME COURT OF THE UNITED STATES

_________________

No. 23–852

_________________

PAMELA BONDI, ATTORNEY GENERAL, et al., PETITIONERS v. JENNIFER VANDERSTOK, et al.

on writ of certiorari to the united states court of appeals for the fifth circuit

[March 26, 2025]

Justice Alito, dissenting.

The Court decides this case on a ground that was not raised or decided below and that was not the focus of the briefing or argument in this Court. Specifically, the Court concludes (1) that respondents mounted a “facial” challenge to a Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) rule implementing provisions of the Gun Control Act of 1968, (2) that a party making such a challenge must meet the test that applies when a statute is challenged as facially unconstitutional (what I will call the Salerno test[1]), and (3) that respondents cannot satisfy that demanding test.[2] If I were satisfied that the Salerno test should control here, I would join the opinion of the Court. The Court points to a gun kit that is all-but-assembled, ante, at 8–9, and a frame that is as close to completion as possible, ante, at 19–20. As applied to those extreme situations, the Court holds—and I agree—the rule does not deviate from the statute. But I am not certain that the Salerno test should govern.

I

Respondents’ petition for review in this case claimed, among other things, that the ATF rule goes beyond what the Gun Control Act permits and that it should therefore be “set aside” under §706(2) of the Administrative Procedure Act, 5 U. S. C. §706(2)(c). See Amended Petition for Review in No. 4:22–cv–00691 (ND Tex.), ECF Doc. 93, pp. 41–42. In the Fifth Circuit and other Courts of Appeals, that provision has long been understood to permit a court to hold that a rule is invalid in toto.[3] Thus, in both the District Court and the Court of Appeals, the parties appear to have proceeded on the assumption that the question presented was simply whether the ATF rule exceeded the agency’s authority under the Gun Control Act. The Government defended the rule as a correct interpretation of those statutory provisions and made no mention of the Salerno test.[4] And for the most part, that was the position advanced in the Government’s briefs in this Court. As the Court points out, however, one paragraph of the Government’s brief did make the Salerno argument. See Brief for Petitioners 27–28. But other than quoting language in INS v. National Center for Immigrants’ Rights, Inc., 502 U.S. 183, 188 (1991) (NCIR), the brief made no effort to explain why that test should apply. And perhaps because of this cursory treatment, none of the respondents addressed the Salerno issue in their briefs or during oral argument. Noting this silence, the Court regards the applicability of the Salerno test as undisputed, and it then proceeds to apply that test. Ante, at 7.

On the record here, I would not hold that respondents agreed that the Salerno test should apply. The Court relies on the use of the term “facial” in their complaints, but that characterization of their challenges did not constitute agreement with the proposition that a facial challenge to a regulation must satisfy the Salerno test. And in fact respondents never conceded that point. They did not address the issue at all in their briefs, and at no point during the lengthy oral argument in this case were they asked about that question. Holding that they conceded the point is unwarranted and extremely unfair. And in any event, we should adjudicate a facial challenge under the right test regardless of the parties’ arguments. See Moody v. NetChoice, LLC, 603 U.S. 707, 779–780 (2024) (Alito, J., concurring in judgment).

II

That brings me to the question whether the Salerno test should apply. In Moody, I set out what I saw as the chief reasons for using that test when a statute is challenged as unconstitutional. See 603 U. S., at 777–778 (opinion concurring in judgment). One of the most important of these is respect for the lawmaking authority of the legislative body that enacted the law in question. Id., at 777. A law passed by Congress or a State Legislature should not be held to be entirely unenforceable just because it would be unconstitutional to apply it in just a few situations. That would represent unjustified judicial interference with the authority of the body entrusted under the Federal Constitution or the constitution of a State with the authority to make law.

This threat to legislative authority is not present when a regulation is challenged. I recognize that two of our decisions support the use of the Salerno test in cases involving facial challenges to rules. See Reno v. Flores, 507 U.S. 292, 301 (1993); NCIR, 502 U. S., at 188. But neither decision explained why the Salerno rule should be extended in that way, and in neither case did the Court grapple with the question that has recently arisen regarding the scope of a court’s authority under §706(2) of the APA.

Applying the Salerno rule in a case in which a rule is challenged under that provision as exceeding the agency’s statutory authority may have far-reaching consequences. As a commentator has observed, “Salerno would seem to dictate that a plaintiff [who challenges a rule] cannot ever win unless he can show that there is ‘no set of circumstances’ in which the regulation would be consistent with the statute. And because it would take an extraordinarily obtuse agency to write a regulation so completely wrong as that, applying Salerno in the statutory context would seem to dictate that plaintiffs would always lose.” S. Buck, Salerno vs. Chevron: What To Do About Statutory Challenges, 55 Admin. L. Rev. 427, 438 (2003). Thus, this extension of Salerno would represent a huge boon for the administrative state.

It would also all but settle the debate about whether §706(2) of the APA authorizes a court to render a rule unenforceable across the board.[5] Respondents asserted a typical claim seeking to have a rule “set aside” in its entirety under §706(2), and if that claim fails because there are at least some situations in which the application of the rule would be lawful, then it seems to follow that virtually all such claims will fail as well. The understanding of the “set-aside” power that has long been prevalent in the courts of appeals will be overturned, and parties who may be adversely affected by a rule will be reduced to filing as-applied challenges. Perhaps that is what the law calls for, but we should not effect such a change without thorough briefing and argument.

For these reasons, I must respectfully dissent. I would either direct the parties to brief the Salerno issue or vacate the judgment below and remand so that the issue can be addressed first by the Court of Appeals.[6]