The Supreme Court’s Illusory Consensus on Ghost Guns

The Supreme Court handed gun manufacturers a defeat on Wednesday by upholding a Biden-era regulation that targeted “ghost guns,” a term used to describe untraceable firearms made from ready-made kits. In a 7–2 decision in Bondi v. Vanderstok, the justices held that the kits could be regulated under existing federal laws.

Justice Neil Gorsuch, writing for the court, held that the Gun Control Act of 1968 “embraces, and thus permits ATF to regulate, some weapon parts kits and unfinished frames or receivers,” referring to the Bureau of Alcohol, Tobacco, and Firearms. Justices Clarence Thomas and Samuel Alito cast the dissenting votes, though Thomas was the only one who rejected the court’s overall reasoning.

Gun-related cases can appear before the Supreme Court in a few different forms. The most impactful cases are the ones decided on constitutional grounds, like the 2008 ruling in District of Columbia v. Heller, which found an individual right to bear arms in the Second Amendment, or the 2022 decision in New York State Rifle and Pistol Association v. Bruen, which laid out a strict test for gun-related restrictions.

Other cases require the court to interpret federal laws instead of the Constitution itself. At issue in this particular case was the Gun Control Act of 1968, or GCA, which sets out the basic framework for how the federal government registers and tracks firearm sales to lawful owners. The law defines a “firearm” as “any weapon … which will or is designed to or may readily be converted to expel a projectile by the action of an explosive” and “the frame or receiver of any such weapon.”

Congress began considering measures that would become the GCA after Lee Harvey Oswald assassinated President John F. Kennedy with a mail-order rifle. Most of the GCA’s focus is on creating a system for registering and tracking firearm sales through licensed dealers to law-abiding customers who pass background checks. The result is that almost every modern gun sold today in the United States is etched with a licensed serial number that can be used to track its ownership—an important tool for law enforcement when conducting investigations.

In recent years, however, some gun manufacturers have offered a way around this regulatory system. In addition to selling fully fabricated firearms, they offer what are known as “weapon parts kits.” Customers could purchase these kits without passing a background check, and manufacturers could sell them without a license. The assembled guns would also lack serial numbers or registered owners, thereby evading the entire federal regulatory regime for gun purchases.

These kits—and the “ghost guns” created with them—drew considerable concern from law enforcement officials, as well as from state and federal leaders. In 2022, ATF drafted a rule that would allow it to regulate weapons parts kits as if they were completed firearms, citing the GCA’s language that covers the “frame or receiver” of such weapons. A coalition of kit manufacturers and gunsmiths sued the bureau before the rule could go into effect, arguing that it went beyond what the GCA allowed it to regulate.

This was an uphill battle for the plaintiffs from the start. When challenging a regulation like this one on its face, they must show that the regulation would be invalid in all circumstances. The government need only prove that it is correct in some cases to prevail. Despite that handicap, the plaintiffs prevailed at first in a federal district court in Texas and then before the Fifth Circuit Court of Appeals. (Given the pronounced rightward tilt of these courts, these results are hardly surprising.)

The Supreme Court saw things differently. As I noted earlier, the GCA’s definition of a firearm includes not just the obvious finished products but also something that “will” or “is designed to” or “may be readily converted” into a gun. It also includes the “frame or receiver” of a gun, which generally refers to the firing mechanism. Gorsuch read this language to include kits that could be easily constructed into a functional firearm, including the Polymer80 “Buy Build Shoot” kit, on which the case was largely focused.

“It comes with ‘all of the necessary components to build’ a Glock-variant semiautomatic pistol,” he wrote, quoting from the Justice Department’s brief. “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.”

Gorsuch rejected the idea that such a kit did not count as a “weapon” for the GCA’s purposes. He noted that the term weapon is an “artifact noun,” a linguistic term for a word that describes a human creation. Everyday speakers often use artifact nouns to describe unfinished versions of an object, Gorsuch explained, citing friend-of-the-court briefs filed by linguistics scholars.

“An author might invite your opinion on her latest novel, even if she sends you an unfinished manuscript,” he wrote. “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.”

Gorsuch showed a judge’s sobriety by not writing, “C’mon, folks, this is an obvious one.” He noted that people would describe a rifle that is partially disassembled for travel and storage as a rifle. And he indicated that the name of Polymer80’s kit gave the game away. “Yes, perhaps a half hour of work is required before anyone can fire a shot,” he wrote. “But even as sold, the kit comes with all necessary components, and its intended function as [an] instrument of combat is obvious. Really, the kit’s name says it all: ‘Buy Build Shoot.’”

Thomas was not the only dissenting justice in the case, but he was the only one who substantively disagreed with Gorsuch on the merits. (Alito wrote that he would have sent the case back to the lower courts on procedural grounds.) His argument largely drew upon fears raised by conservative judges in the lower courts about the ATF’s decision to regulate unfinished frames and receivers under the statutory term of “frame or receiver.”

“If an object already is what it may be converted into, then semiautomatic AR-15s would seem to be partially complete, automatic machineguns,” Thomas warned. “This reasoning exposes the manufacturers, sellers, and owners of AR-15s to criminal liability under the [National Firearms Act]. But, Congress does not ‘hide elephants in mouseholes.’ 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.”

This is not a very realistic prospect, to say the least. It verges on the conspiratorial for Thomas to suggest that ATF is sneaking some sort of backdoor effort to criminalize roughly 16 million AR-15 owners through this rule change. (Note that the Trump administration did not reverse the outgoing Biden administration’s stance in this case after taking office.) In response to this claim from Thomas and the plaintiffs, Gorsuch took pains to note that the Justice Department denied it had any such plans and hinted that the court would almost certainly not interpret the GCA or the National Firearms Act, which regulates fully automatic firearms, in such a way.

This will likely not be the end of legal battles over weapons parts kits and ghost guns. Again, the government only had to prove that the ATF rule was a valid interpretation of the statute in some cases, not all of them. And while there is broad consensus among the justices—excluding Thomas, of course—that ATF can regulate the kits, there appears to be some daylight between them on how far the bureau can go.

Justice Brett Kavanaugh, for example, wrote a short concurring opinion to emphasize the state-of-mind requirement in the relevant federal firearms laws. Those laws require that a defendant have acted “willfully” to be criminally charged with violating them—not inadvertently, accidentally, or so on. “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,” Kavanaugh noted.

Alito, for his part, focused his dissenting opinion on procedural questions about the standard of review that the court should apply. But he also wrote that dissent in such a way as to suggest that the court’s opinion was a very narrow one. “The Court points to a gun kit that is all-but-assembled, and a frame that is as close to completion as possible,” Alito wrote. “As applied to those extreme situations, the Court holds—and I agree—the rule does not deviate from the statute.”

That drew pushback from Justice Sonia Sotomayor, who rejected the idea that the court had only signed off on “all-but-assembled” kits and frames “as close to completion as possible,” as Alito had slyly implied. “The court’s opinion speaks for itself on that point and others,” she wrote. “I encourage readers to go to the source, rather than rely on dissents, to understand what the court holds. It is the court’s ruling, not the one set forth by the dissents, that binds the lower courts.”

Alito, via a footnote, fired back. “Although Justice Sotomayor obviously wishes that the court had gone further, all that the court has actually held is that the ATF rule is not facially invalid because at least some applications of the rule are consistent with the statute,” he wrote, citing the two examples noted by Gorsuch. “The court has not held that any other kits or presently non-functional receivers are covered.”

So potent is the issue of gun rights that even in a case where the justices largely agreed with one another, they couldn’t help but find ways to part ways.