OPINION ANALYSIS
on Mar 26, 2025
at 11:50 am

The court heard Bondi v. VanDerStok at the start of the term in October. (Amy Lutz via Shutterstock)
This article was update on March 26 at 2:04 p.m.
The Supreme Court on Wednesday upheld a Biden-era rule regulating so-called âghost gunsâ â untraceable weapons without serial numbers, assembled from components or kits that can be bought online. By a vote of 7-2, the justices held that the Gun Control Act of 1968 allows the Bureau of Alcohol, Tobacco, Firearms, and Explosives to regulate at least some ghost guns, although they left open the possibility that the rule might not apply in individual challenges to particular ghost guns.
Justice Clarence Thomas dissented from the courtâs decision, complaining that it had agreed to ârewrite statutory text.â Justice Samuel Alito wrote his own dissent in which he contended that his colleagues had applied the wrong test to determine whether the ATF rule was valid.
The ATF adopted the rule in 2022 to address what it characterizes as an âexponentialâ increase in ghost guns. The Gun Control Act defines a âfirearmâ as âany weapon ⦠which will or is designed to or may readily be converted to expel a projectile by the action of an explosive,â including âthe frame or receiver of any such weapon.â
The ATF contended that the 2022 rule was consistent with the language of the law because it defines âfirearmâ to include products, such as gun kits, that can be converted into an operational gun or a functional frame (the basic structure of the gun) or receiver (the part of the gun that houses the firing mechanism). The rule also clarified that the terms âframeâ and âreceiverâ include partially complete or disassembled frames or receivers that can be âreadilyâ completed or converted to work as a frame or receiver.
But a group that included two individual gun owners and a gun-rights advocacy group went to federal court in Texas to challenge the rule. A federal district judge in Fort Worth prohibited the agency from applying the rule anywhere in the United States.
Although the conservative U.S. Court of Appeals for the 5th Circuit largely upheld that decision, a divided Supreme Court put the district judgeâs order on hold, allowing the Biden administration to enforce the rule while it appealed. Four justices â Clarence Thomas, Samuel Alito, Neil Gorsuch, and Brett Kavanaugh â indicated that they would have denied the governmentâs request then.
In a 24-page opinion by Gorsuch on Wednesday, the court upheld the rule.
Congress enacted the Gun Control Act, Gorsuch explained, because it found that then-current âgun control measures ⦠allowed criminals to acquire largely untraceable guns too easily.â The act requires manufacturers to put a serial number on guns and regulates commercial gun sales by (among other things) requiring gun manufacturers and dealers to conduct background checks and keep records of gun sales.
Advances in technology, Gorsuch noted, such as 3D printing and reinforced polymers, have changed the way in which guns are manufactured and sold. And in particular, âcompanies are able to make and sell weapon parts kits that individuals can assemble into functional firearms in their own homes.â These kits are popular among hobbyists, Gorsuch wrote, but also among criminals, because some manufacturers and sellers do not regard them as âfirearmsâ subject to the Gun Control Act and therefore do not comply with the actâs requirements â leading to âan explosion of crimesâ around the country.
Gorsuch emphasized that the challengers in this case were not asking the Supreme Court to decide whether the rule regulating ghost guns could be applied to specific kinds of ghost guns â that is, to âparticular weapons parts kits or unfinished frames or receivers.â Instead, he stressed, the challengers had asked the courts to hold that the rule could not be applied to any ghost guns. But the Supreme Court declined to do so.
First, Gorsuch explained, the Gun Control Act allows the ATF to regulate weapons parts kits. The text of the act, he reasoned, imposes two criteria. First, there must be a âweapon.â And the âweaponâ must âbe able to expel a projectile by the action of an explosive,â be âdesigned to do so,â or be âsusceptible of ready conversion to operate that way.â
In contrast with the 5th Circuit, Gorsuch concluded that âat least some kits will satisfy bothâ of these requirements. He used as an example a kit named the âBuy Build Shootâ kit, by a company called Polymer80, that allows the buyer to quickly and easily build a âGlock-variant semiautomatic pistol.â An âordinary speaker might well describe the âBuy Build Shootâ kit as a âweapon,ââ Gorsuch posited, even if âperhaps a half hour of work is required before anyone can fire a shot.â He noted that âeven as sold, the kit comes with all necessary components, and its intended function as instrument of combat is obvious. Really, the kitâs name says it all: âBuy Build Shoot.ââ Â
And the âBuy Build Shootâ kit also meets the second criterion, because it can be âreadily convertedâ into a firearm, âfor it requires no more time, effort, expertise, or specialized tools to completeâ than a starter gun, which is explicitly mentioned in the Gun Control Act.
Gorsuch acknowledged that â[w]eapons parts kits vary widelyâ and âmay require more time, expertise, or specialized tools to finish.â But the Supreme Court does not need to decide in this case when âa kit may be so incomplete or cumbersome to assemble thatâ the ATF can no longer regulate it under the Gun Control Act, he determined.
Gorsuch concluded, again in contrast to the 5th Circuit, that the Gun Control Act also allows the ATF to regulate partially finished frames and receivers. Gorsuchâs opinion offered a picture of a âcomplete frame of a Glock-variant firearmâ above a picture of a âpartially complete frameâ sold by Polymer80, highlighting what he described as the âmain differencesâ between the two â a pair of plastic tabs that the buyer would need to remove, and then add pins. Here too he observed that âan ordinary speaker might well call Polymer80âs product a firearm âframeâ even though a little work is required to complete. Just look again at the second photo,â Gorsuch pleaded. âWhat else would you call it?â
Gorsuch added that the ATF has in the past âconsistently interpretedâ the Gun Control Act to apply to at least some unfinished frames and receivers, âincluding ones no more finished than Polymer80âs product.â These âcontemporary and consistent viewsâ âcan provide evidence of the lawâs meaning,â he noted. And indeed, he continued, the challengers say that that they do not dispute the ATFâs âprior practiceâ â âa concession that all but gives the game away.â Although the challengers contend that the new rule regulating âghost gunsâ goes too far, he said, âfor our purposes, what matters is that even the plaintiffs do not really insist thatâ the rule âreaches only finished frames and receivers.â
As with weapons parts kits, Gorsuch conceded that the courtâs âreasoning has its limits.â âSome products,â he wrote, âmay be so far from a finished frame or receiver that they cannot fairly be described using those terms. But this case,â he wrote, ârequires us to explore none of that.â
Gorsuch rejected the challengersâ request to rule in their favor based on either the rule of lenity â the idea that when a criminal law is ambiguous, it should be applied in the way that is most favorable to the defendant â or the doctrine of constitutional avoidance, which instructs courts to avoid ruling on constitutional issues unless it is absolutely necessary. Gorsuch, perhaps the courtâs strongest advocate for the rule of lenity, countered that âneither lenity nor avoidance has any role to play where âtext, context, and structureâ decide the case.â âThe Gun Control Act embraces,â Gorsuch concluded, and thus permits ATF to regulate, some weapons parts kits and unfinished frames or receivers, including those we have discussed.â
Justice Brett Kavanaugh wrote a two-page concurring opinion in which he observed that the line between ghost guns to which the ATFâs rule (and therefore the requirements of the Gun Control Act, such as background checks, licensing, and serial numbers) does or does not apply âis not entirely clear.â Individuals can face criminal liability for violating most of those requirements only if the government can show that they knew their conduct was illegal, Kavanaugh noted â a high bar.
But someone who violates the background-check requirement, Kavanaugh continued, is subject to a lower standard, and can face criminal liability even if they were unaware that they were violating the law. Kavanaugh suggested that the federal government would avoid the potential fairness problems that could arise in such a situation âby adhering to its oral-argument representation that it would likely decline to bring charges in those circumstances.â
Justice Sonia Sotomayor was less concerned about the issues that Kavanaugh raised, deeming them âunfoundedâ in her own two-page concurring opinion. Firearms manufacturers and dealers have long complied with the Gun Control Actâs requirements, she wrote, and âATFâs rule should come as no surprise.â But to the extent that manufacturers arenât sure about whether the rule applies to their products, she contended, the ATF âencouragesâ them to seek guidance from the agency. âManufacturers have long taken advantage of that process,â she added, âand a failure to do so might suggest willfulness on their part.â
Thomas would have held that the ATF rule was not authorized by the Gun Control Act. In his view, the âordinary meaning of âframe or receiverâ does not includeâ unfinished frames or receivers. Similarly, although âan object that âmay readily be convertedâ into a gun qualifies as a âfirearmâ if that object is already a âweapon,â an object that is not already a weapon does not.â And here, he said, the âordinary meaning of âweaponâ does not include weapons-parts kits,â which are âunfinishedâ and âinoperable.â But at the very least, Thomas continued, the Gun Control Act is ambiguous, which would call for the application of the rule of lenity. Â
âCongress,â Thomas concluded, âcould 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.â
Alito disagreed with the majorityâs decision to use the same test that courts use when reviewing challenges to the constitutionality of laws as they are written, without regard to particular facts. The challengers in this case, he contended, had not agreed that such a test should apply, and the federal government gave it only âcursory treatmentâ in its brief.
Alito also questioned whether the test, known as the Salerno test, should apply. In the courtâs decision last July sending First Amendment challenges to Florida and Texas laws regulating large internet platforms back to the lower courts for another look, Alito explained, he wrote that one important reason to use the Salerno test âis respect for the lawmaking authority of the legislative body that enacted the law in question.â But that âthreat to legislative authority is not present when a regulation is challenged,â he noted. He therefore would have either instructed the litigants in the case to brief this issue or send the case back to the lower court for it to consider it.
This article was originally published at Howe on the Court.Â





