PAMELA BONDI, ATTORNEY GENERAL, ET AL., PETITIONERS v. JENNIFER VANDERSTOK, ET AL.
No. 23-852
SUPREME COURT OF THE UNITED STATES
March 26, 2025
604 U. S. ____ (2025)
GORSUCH, J.
CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIFTH CIRCUIT; Argued October 8, 2024
Syllabus
NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.
SUPREME COURT OF THE UNITED STATES
Syllabus
BONDI, ATTORNEY GENERAL, ET AL. v. VANDERSTOK ET AL.
CERTIORARI
No. 23–852. Argued October 8, 2024—Decided March 26, 2025
The Gun Control Act of 1968 (GCA) requires those engaged in importing, manufacturing, or dealing in firearms to obtain federal licenses, keep sales records, conduct background checks, and mark their products with serial numbers. The Act defines “firearm” to include “(A) any weapon ... 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.”
In 2022, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) adopted a rule interpreting the Act to cover weapon parts kits that are “designed to or may readily be converted to expel a projectile,” 27 CFR §478.11, and “partially complete, disassembled, or nonfunctional” frames or receivers, §478.12(c). Before ATF could enforce its rule, gun manufacturers and others filed what they described as a facial challenge under the Administrative Procedure Act, arguing that the GCA cannot be read to reach weapon parts kits or unfinished frames or receivers. The District Court agreed and vacated the rule. The Fifth Circuit affirmed, holding that
Syllabus
Held: The ATF‘s rule is not facially inconsistent with the GCA. Pp. 7–24.
(a) Section 478.11‘s provisions addressing weapon parts kits are not facially invalid under
(b) Section 478.12(c)‘s treatment of partially complete frames and receivers is also not facially invalid under
(c) The plaintiffs’ arguments about the linguistic differences between subsections (A) and (B) and potential unintended consequences under the National Firearms Act (NFA) are unpersuasive. The government represents that AR–15 receivers do
Syllabus
Pp. 21–24.
(d) Neither the rule of lenity nor constitutional avoidance applies where, as here, the statute‘s text, context, and structure make clear it reaches some weapon parts kits and unfinished frames or receivers. P. 24.
86 F. 4th 179, reversed and remanded.
GORSUCH, J., delivered the opinion of the Court, in which ROBERTS, C. J., and SOTOMAYOR, KAGAN, KAVANAUGH, BARRETT, and JACKSON, JJ., joined. SOTOMAYOR, J., KAVANAUGH, J., and JACKSON, J., each filed concurring opinions. THOMAS, J., and ALITO, J., each filed dissenting opinions.
Opinion of the Court
NOTICE: This opinion is subject to formal revision before publication in the United States Reports. Readers are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, pio@supremecourt.gov, of any typographical or other formal errors.
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 GORSUCH delivered the opinion of the Court.
For decades, the Gun Control Act has regulated the sale of firearms. This case poses the question whether the Act‘s longstanding mandates also apply to those who make and sell a new product—“weapon parts kits.”
I
A
Shortly after the assassinations of Senator Robert F. Kennedy and Dr. Martin Luther King, Jr. stunned the Nation, Congress adopted the Gun Control Act of 1968 (GCA).
These mandates serve at least two ends. The background-check requirement seeks to keep “guns out of the hands of criminals.” Abramski v. United States, 573 U. S. 169, 180 (2014). The licensing, recordkeeping, and serialization requirements, meanwhile, aim “to assist law enforcement authorities in investigating serious crimes,” ibid., by permitting them “to determine where, by whom, or when” a firearm was manufactured and to whom it was “sold or otherwise transferred.” 87 Fed. Reg. 24652 (2022). Today, thousands of law-enforcement agencies nationwide depend on the Act‘s tracing system to link firearms involved in crimes to their owners. Id., at 24659.
The GCA‘s mandates apply to “firearm[s].” See
Recent years, however, have witnessed profound changes in how guns are made and sold. When Congress adopted the GCA in 1968, “the milling equipment, materials needed, and designs were far too expensive for individuals to make firearms practically or reliably on their own.” 87 Fed. Reg. 24688. With the introduction of new technologies like 3D printing and reinforced polymers, that is no longer true. Today, companies are able to make and sell weapon parts kits that individuals can assemble into functional firearms in their own homes. Ibid.
These kits vary widely both in how complete they come and in how much work is required to finish them. At one end of the spectrum, a kit may lack essential parts and “requir[e] substantial effort, specialized expertise, uncommon equipment, and a significant amount of time” before anyone can fire a shot. Brief for Former Acting Chief of ATF Firearms Technology Branch et al. as Amici Curiae 35. At the other end, some kits “contain all components necessary” for “a complete pistol” and can be completed in perhaps half an hour using commonly available tools. App. to Pet. for Cert. 236a.
Sales of these kits have grown “exponential[ly].” Brief for Petitioners 2. Home hobbyists enjoy assembling them. VanDerStok v. Garland, 86 F. 4th 179, 185 (CA5 2023). But criminals also find them attractive. Id., at 195. That is largely due to how the kits are sold. Some manufacturers and dealers take the position that weapon parts kits do not qualify as “firearms” subject to the GCA. As a result, they say, they are free to sell their products without obtaining a federal license, conducting background checks, maintaining sales records, or marking components with serial numbers. 87 Fed. Reg. 24652.
The upshot? “[P]olice departments around the Nation” have “confronted an explosion of crimes” involving these “ghost guns.” Brief for Petitioners 8. In 2017, law-enforcement agencies submitted about 1,600 ghost guns to the federal government for tracing. App. to Pet. for Cert. 194a. By 2021, that number jumped to
B
In 2022, the Bureau of Alcohol, Tobacco, Firearms and Explosives adopted a new rule designed to combat the proliferation of ghost guns. See 87 Fed. Reg. 24652. In doing so, the agency invoked authority Congress granted it to prescribe “rules and regulations as are necessary to carry out” the GCA.
The first addresses weapon parts kits directly. Recall that
The second relevant aspect of the agency‘s new rule concerns a key building block of almost any firearm: its frame or receiver. Under subsection (B) of
In its 2022 rule, ATF sought to expand this definition. Now, the agency said, a “frame or receiver” subject to subsection (B) of
Before ATF‘s new rule took effect and ATF could begin efforts to enforce its new rule, various gun manufacturers, at-home gunsmiths, and others filed what they described as a “facial” challenge under the Administrative Procedure Act (APA). See, e.g., BlackHawk Mfg. Complaint in No. 22–619 (ND Tex., Oct. 20, 2022), ECF Doc. 99, p. 25. They argued that the GCA cannot be fairly read to reach weapon parts kits or unfinished frames or receivers. As a result, the plaintiffs contended, ATF‘s regulations in §478.11 and §478.12(c) purporting to extend the GCA‘s mandates to these products could not be enforced against anyone and had to be “set aside” as impermissibly issued “in excess of statutory ... authority.”
At summary judgment, the district court agreed with the plaintiffs and vacated the agency‘s new rule. VanDerStok v. Garland, 680 F. Supp. 3d 741, 766 (ND Tex. 2023). On appeal, the Fifth Circuit largely affirmed. The court acknowledged that subsection (A) of
The government sought review in this Court. Our intervention was necessary, the government insisted, because the court of appeals had “adopted an interpretation of the Act that would effectively nullify its central provisions” and leave criminals today nearly as free to obtain “untraceable firearms” as they were before the Act‘s adoption in 1968. Pet. for Cert. 28. We agreed to hear the case. 601 U. S. ____ (2024).
II
As presented to us, this case does not ask us to resolve whether ATF‘s new regulations in §478.11 and §478.12 may be lawfully applied to particular weapon parts kits or unfinished frames or receivers. Instead, the plaintiffs have pursued what the lower courts called a “facial” pre-enforcement challenge to the agency‘s authority to regulate any weapon parts kits or unfinished frames or receivers. VanDerStok, 680 F. Supp. 3d, at 766; VanDerStok, 86 F. 4th, at 186. In a challenge like that, the government represents, “‘the possibility that [ATF‘s regulation] may be invalid as applied’ in some cases ‘does not mean that the regulation is facially invalid.’ Instead, [the plaintiffs‘] burden is to show that the Rule itself is inconsistent with the statute on its face.” Brief for Petitioners 27–28 (quoting INS v. National Center for Immigrants’ Rights, Inc., 502 U. S. 183, 188 (1991) (addressing a facial challenge under the Immigration and Nationality Act)). Nowhere in either of their briefs before us do the plaintiffs dispute that assessment. Accordingly, we take it as given for our purposes here.2
In doing so, we turn first to the question whether §478.11‘s provisions addressing weapon parts kits are inconsistent on their face with the GCA. The answer turns on subsection (A) of
A
To appreciate why, it helps to work with an example. Take a weapon parts kit featured prominently in the record before us: Polymer80‘s “Buy Build Shoot” kit. It comes with “all of the necessary components to build” a Glock-variant semiautomatic pistol. App. to Pet. for Cert. 219a. And it is so easy to assemble that, in an ATF test, an individual who had never before encountered the kit was able to produce a gun from it in 21 minutes using only “common” tools and instructions found in publicly available YouTube videos. Id., at 220a. The first picture below shows the kit; the second depicts the gun the kit yields.
Now, assess whether the “Buy Build Shoot” kit meets subsection (A)‘s two tests, and start with the question whether Polymer80‘s offering qualifies as a “weapon.” When Congress adopted the GCA in 1968, that term meant what it means today: “an instrument of offensive or defensive combat ... [such] as a club, sword, gun, or grenade.” Webster‘s Third New International Dictionary 2589 (def. 1) (1966); accord, 1 Concise Oxford English Dictionary 1476 (def. 1) (5th ed. 1964). As a result, ATF‘s authority under subsection
Plainly, the finished “Buy Build Shoot” kit is an instrument of combat. No one would confuse the semiautomatic pistol pictured above with a tool or a toy. Of course, as sold, the kit requires some assembly. But a number of considerations persuade us that, even as sold, the “Buy Build Shoot” kit qualifies as a “weapon.”
Consider, first, a feature of ordinary language. The term “weapon” is an artifact noun—a word for a thing created by humans. Artifact nouns are typically “characterized by an intended function,” rather than by “some ineffable ‘natural essence.‘” S. Grimm & B. Levin, Artifact Nouns: Reference and Countability, in 2 Proceedings of the 47th Annual Meeting of the North East Linguistic Society (NELS 47) 55 (2017).3 Reflecting as much, everyday speakers sometimes use artifact nouns to refer to unfinished objects—at least when their intended function is clear. An author might invite your opinion on her latest novel, even if she sends you an unfinished manuscript. A friend might speak of the table he just bought at IKEA, even though hours of assembly remain ahead of him. In both cases, the artifact noun fits because the intended function of the unfinished object is obvious to speaker and listener alike.
The term weapon can work this way, too. Imagine a rifle disassembled for storage, transport, or cleaning. It may take time to render the rifle useful for combat, but its intended function is clear. And, as a matter of every day speech, that rifle is a weapon, whether disassembled or combat ready. In the same way and for the same reason, an ordinary speaker might well describe the “Buy Build Shoot” kit as a “weapon.” Yes, perhaps a half hour of work is required before anyone can fire a shot. But even as sold, the kit comes with all necessary components, and its intended function as instrument of combat is obvious. Really, the kit‘s name says it all: “Buy Build Shoot.”
Next, consider what the statute itself has to say about the term “weapon.” Subsection (A) tells us that the term “includ[es] a starter gun.”
Finally, notice another feature of the statute. If Congress had wanted to regulate only operable firearms, it could have simply addressed “weapons” that can “expel a projectile by the action of an explosive.” But Congress didn‘t stop there. Instead, Congress explained that a “weapon” also qualifies for regulation if it is either
Of course, to implicate the Act, not only must a “weapon” be present. That weapon must meet one of the just-recounted conditions. At a minimum, that means a weapon must be capable of being “readily ... converted to expel a projectile by the action of an explosive.” Ibid. As we see it, the “Buy Build Shoot” kit satisfies that test, too.
Begin with what we can glean about the “ready-conversion” standard from the statute. We know that Congress‘s direction that a starter gun is a “weapon” would be pointless unless a starter gun satisfies all subsection (A)‘s terms. For the statute to make sense, then, a starter gun must be able to fire bullets, designed to do so, or capable of ready conversion to operate that way. Generally, however, a starter gun meets neither of the first two conditions, for its barrel is deliberately blocked. See United States v. 16,179 Molso Italian .22 Caliber Winlee Derringer Convertible Starter Guns, 443 F. 2d 463, 465 (CA2 1971). That leaves only one serious possibility: It must be that a starter gun “can readily be converted to expel projectiles by the action of an explosive.”
That turns out to tell us all we need to know about the statute‘s “ready conversion” test. As we have seen, a person without any specialized knowledge can convert a starter gun into a working firearm using everyday tools in less than an hour. Mullins, 446 F. 3d, at 755. And measured against that yardstick, the “Buy Build Shoot” kit can be “readily converted” into a firearm too, for it requires no more time, effort, expertise, or specialized tools to complete. App. to Pet. for Cert. 220a. If the one meets the statutory test, so must the other.
Admittedly, our reasoning here has its limits. Just because some kits, like Polymer80‘s, qualify as “weapons” that “can readily be converted” into working firearms does not mean all do. Think of the problem of the heap: Start with a heap of sand and begin removing grains; at some point, a heap no longer exists. That problem attends many artifact nouns. Even when used to capture unfinished products, artifact nouns generally reach only so far. It would be extravagant to speak of a novel when the author has dashed off only a few lines. Few would call a pile of unfinished logs a table. Subsection (A) may present a similar problem. Weapon parts kits vary widely. See Part I–A, supra. Not all come as complete as the “Buy Build Shoot” kit. Some, too, may require more time, expertise, or specialized tools to finish. And at some point a kit may be so incomplete or cumbersome to assemble that it can no longer fairly be described as a “weapon” capable of “read[y] ... conver[sion]” into a working firearm.
While we recognize the problem, this case does not require us to untangle exactly how far subsection (A) reaches. The plaintiffs argue only that §478.11‘s provision addressing weapon parts kits is facially inconsistent with the statute. The Fifth Circuit adopted the same view after coming to the unqualified conclusion that weapon parts kits can never satisfy the statute‘s two tests. To resolve this case, it is enough to say those assessments are mistaken. Because at least some weapon parts kits satisfy both of subsection (A)‘s tests, §478.11 is not facially invalid. Future cases may present other and more
B
The plaintiffs dispute little of what we have said. They admit that artifact nouns sometimes capture unfinished articles. Tr. of Oral Arg. 76–77. They recognize that starter guns qualify as “weapons” even though they require work before they operate as functional firearms. Brief for Respondent VanDerStok 34. The plaintiffs concede, too, that disassembled rifles and guns are “weapons” that can be “readily ... converted” to live fire because they have “all the parts necessary” for an ordinary person “to put together a functioning firearm” in short order. Id., at 37. Really, the plaintiffs fail only to take the next step and acknowledge that the same might be said of some weapon parts kits.
Given all that, what do the plaintiffs have to say in support of the Fifth Circuit‘s conclusion that subsection (A) reaches no weapon parts kits? Perhaps their best argument centers on the fact that other statutes address collections of parts while this one does not. As the plaintiffs observe, Congress has elsewhere defined a “destructive device” to embrace “any combination of parts from which a destructive device may be readily assembled.”
The plaintiffs’ conclusion, however, does not follow from their premise. We do not doubt that subsection (A) sweeps more narrowly than some other statutes. No one thinks it reaches every piece or part that can be used to produce a firearm. Recognizing as much, ATF itself acknowledges that subsection (A) does not allow it to regulate “standalone triggers, barrels, stocks, or magazines.” Brief for Petitioners 24. Nor, the agency admits, does the statute authorize it to regulate “weapon parts kits writ large,” without regard to how complete they come or how difficult they are to assemble. Ibid. But the fact that subsection (A) doesn‘t go as far as some other statutes does not tell us how far it does go. Let alone prove that subsection (A) fails, as a categorical matter, to reach any weapon parts kits.
Faced with that problem, the plaintiffs, joined now by the dissent, try another tack. They object that weapon parts kits cannot be “weapons” under subsection (A) because they lack functional frames or receivers. See Brief for Respondent VanDerStok 35; post, at 20–21 (opinion of THOMAS, J.) (advancing a similar argument). That conclusion rests on two premises: (1) that a “weapon” must have a fully “functional” frame or receiver, and (2) that no “weapon parts kit” includes such a part. Post, at 20–21 (opinion of THOMAS, J.). But neither premise is sound. For one, the statute nowhere says that a “weapon” must have a fully functional frame or receiver—nor is it obvious how we might derive such a rule from its terms. In fact, as we have seen, subsection (A) reaches any “weapon” that may “readily be converted” to live fire.
Failing all else, the dissent suggests that other criminal statutes addressing “firearm[s]” prove that weapon parts kits cannot fall within the statutory definition of that term. Post, at 22. So, for example, the dissent observes that Congress has penalized the use of “firearm[s]” during and in relation to a “crime of violence,”
This argument suffers at least two problems as well. First, what the dissent finds hard to imagine turns out to be anything but, for various criminal laws addressing firearms can apply to weapon parts kits. Just consider some of the laws we have already encountered that require those who import, manufacturer, or deal in “firearms” to obtain federal licenses, keep records of their sales, and conduct background checks.
Second, the dissent‘s complaint is hardly resolved by adopting its view of the statute. The dissent must acknowledge, for example, that standalone “frame[s] or receiver[s]” and “silencer[s]” qualify as “firearms,” for the statute tells us so expressly.
That leaves the question whether ATF‘s new regulation addressing unfinished frames and receivers, §478.12(c), is facially inconsistent with the GCA. The answer here turns on subsection (B) of
A
Working with another example drawn from the record helps illustrate why this is so. The first photograph below depicts the complete frame of a Glock-variant firearm, the second a partially complete frame that Polymer80 sells.
App. 259, 263.
The main differences between the completed frame and Polymer80‘s product are the plastic tabs circled in red. Brief for Petitioners 34-35. The record suggests that those tabs “are easily removable by a person with novice skill, using common
A number of reasons persuade us that this qualifies as a “frame” for purposes of subsection (B). First, like the word “weapon” in subsection (A), the terms “frame” and “receiver” in subsection (B) are artifact nouns. And, as artifact nouns, they may sometimes describe not-yet-complete objects. Recall the author who refers to her manuscript as a novel, or your friend who calls his IKEA kit a table. In much the same way, an ordinary speaker might well call Polymer80‘s product a firearm “frame,” even though a little work is required to complete it. Just look again at the second photo. What else would you call it?
Next, consider how the GCA uses the words “frame” and “receiver” elsewhere. Section 923(i) spells out the Act‘s serialization mandate. It requires those who make or sell “firearms” to identify their products “by means of a serial number engraved or cast on the receiver or frame.” Though this directive may seem simple enough, it is complicated by the fact that the statutory definition of “firearm” includes some incomplete “weapon[s],” “muffler[s],” “silencer[s],” and “destructive device[s].”
Here, too, examples help. Imagine a handgun that is otherwise ready to shoot, but contains Polymer80‘s incomplete frame. An ordinary person, using ordinary tools, can finish the frame in minutes. App. 262. For reasons explored in Part II, supra, that gun is a weapon capable of ready conversion into a working firearm under subsection (A). So
The novelty of the plaintiffs’ complete-items-only reading of subsection (B) supplies another strike against it. Without question, ATF‘s new rule seeks to regulate a greater variety of unfinished frames and receivers than the agency has in the past. But it is equally true that, for decades, the agency has consistently interpreted subsection
Last but not least, the plaintiffs represent that they have no “quarrel” with ATF‘s “prior practice.” Tr. of Oral Arg. 59. It is a concession that all but gives the game away. Of course, the plaintiffs think the agency‘s new rule reaches further than the statute can bear by seeking to regulate some products too far removed from finished frames or receivers. But, for our purposes, what matters is that even the plaintiffs do not really insist that subsection (B) reaches only finished frames and receivers.
Here, again, our reasoning has its limits. In saying that a product like Polymer80‘s qualifies as a “frame,” we do not suggest that the GCA reaches, and ATF may regulate, any combination of parts susceptible of conversion into a frame or receiver with sufficient time, tools, and expertise. Like the term “weapon,” the artifact nouns “frame” and “receiver” have their bounds. Some products may be so far from a finished frame or receiver that they cannot fairly be described using those terms. But this case requires us to explore none of that. The plaintiffs do not challenge ATF‘s new rule as applied to particular products. They argue only that
B
Resisting our conclusion on this score, the plaintiffs and dissent press three main replies.
First, they point to a linguistic difference between subsections (A) and (B). In subsection (A), Congress chose to regulate “weapons” that “can readily be converted” into operating firearms. Meanwhile, in subsection (B) Congress spoke only of “frames or receivers,” not parts that “can readily be converted” into those things. And, as the plaintiffs see it, that omission counsels against reading subsection (B) to reach any unfinished frames or receivers. Brief for Respondent VanDerStok 19; see also post, at 11-12 (THOMAS, J., dissenting) (making a similar point).
This argument fails to persuade us for a number of familiar reasons. For one, it does not account for the fact that ordinary speakers sometimes use unadorned artifact nouns like “weapon,” “frame,” or “receiver” to reach unfinished articles. Adopting the plaintiffs’ argument would also require us to read the phrase “frame or receiver” in
Even beyond all that, reading subsection (B) in light of subsection (A) does more to undermine than to advance the plaintiffs’ cause. Subsection (B) speaks of the “frame or receiver of any such weapon.”
Second, the plaintiffs and the dissent contend, our interpretation of subsection (B) could invite a serious unintended consequence under a separate statute, the
The plaintiffs’ fears are misplaced. The government represents that AR-15 receivers do not “qualify as the receiver of a machinegun.” Reply Brief 12. Nor, the government emphasizes, has ATF ever “suggested otherwise.” Ibid. Much the same can be said of our reasoning today. As we have stressed, a statute‘s text and context are critical to determining whether (and to what extent) Congress used an artifact noun to reach unfinished objects. And, without doubt, the NFA and the GCA are different statutes passed at different times to address different problems using different language. Our analysis of the GCA thus does not begin to suggest that ATF possesses authority to regulate AR-15 receivers as machineguns under the NFA.
Third, the plaintiffs criticize ATF‘s rule for permitting the agency to consider “jigs,” “tools,” and “instructions” when deciding whether an incomplete “frame or receiver” is close enough to the finished product to fall under subsection (B). Brief for Respondent VanDerStok 25-26. The dissent echoes the complaint, offering a photo from the record depicting various tools and jigs. See post, at 14 (opinion of THOMAS, J.). But if this is a problem at all, it is one for another day. As litigated, this case does not call on us to address
*
The plaintiffs close by asking us to invoke the rule of lenity or the doctrine of constitutional avoidance to resolve in their favor any ambiguities about
It is so ordered.
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
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));
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.
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
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.”
As to background-check violations, by contrast, the statute penalizes violations committed “knowingly.”
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.
JUSTICE JACKSON, concurring.
To me, the nature of the claim at issue in this case makes its resolution quite
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.
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
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
In 1968, Congress replaced the FFA with the
The GCA sets forth a narrower definition of “firearm” than the FFA did. Its definition, which governs all of “Chapter 44—Firearms,”
“(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.
Congress left the terms “frame” and “receiver” undefined. See
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,”
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,
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.
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
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
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
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, 745 (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 reg-
ulatory 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
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
Cite as: 604 U. S. ____ (2025) 9 THOMAS, J., dissenting 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 10 BONDI v. VANDERSTOK THOMAS, J., dissentingIII
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,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“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.”
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.”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