In April, the U.S. Supreme Court agreed to take up a case challenging the Biden administration’s efforts to curb the sale of homemade, untraceable “ghost guns” that are frequently used in crimes.

The case seeks to topple a rule imposed by the Bureau of Alcohol, Tobacco, Firearms and Explosives that requires sellers of “ready to build” ghost gun kits to add serial numbers to some parts and conduct background checks on prospective buyers. 

But legal experts say the stakes are much higher. A ruling against the federal government could broaden Second Amendment protections, jeopardizing numerous laws governing the manufacture and sale of firearms.

“The Supreme Court may want to expand Second Amendment protections from the right to own and carry a firearm to the right to make firearms and to sell them,” said Timothy Lytton, a law professor at Georgia State University. 

Such an outcome could do away with bans or restrictions on ghost guns in California, New Jersey, and at least 11 other states. The ruling could also pave the way for lower courts to overturn requirements for gun manufacturers and dealers to obtain federal licenses, be inspected by the government, and maintain sales records.

A federal district court in Texas and the Fifth Circuit Court of Appeals struck down the ghost gun rule in 2023. Lytton said these lower court opinions wrestled with more sweeping questions about the limits of the Second Amendment, teeing up the justices to do the same. Those opinions, he said, “may have larger implications for the Supreme Court’s analysis, and that may be Second Amendment implications.”  

The challenge comes two years after the Supreme Court’s landmark Bruen ruling, which established that gun regulations must be consistent with the country’s historical tradition of firearm regulations to be considered constitutional. In court filings concerning the ghost guns rule, gun manufacturers and gun rights organizations have seized on Bruen’s history and tradition test by arguing that early Americans often acquired firearms through homemade means. 

President Biden directed the ATF to regulate ghost guns after they were used in a spate of high-profile shootings and increasing evidence emerged that homemade weapons were being used in crimes. A March 2023 ATF report found that between 2016 and 2022, law enforcement recovered more than 72,000 ghost guns. More than 1,200 of those weapons surfaced in connection to homicides and attempted homicides. 

“Ghost guns continue to be a problem,” said Graham Barlowe, a former ATF agent, pointing out that millions of ghost guns sold before the new rule took effect remain in circulation. “Criminal elements seek out ghost guns because they are available, and they are anonymous.” 

The ATF’s ghost gun rule, implemented in 2022, broadened the legal definition of a firearm to include kits sold with parts and tools to build ghost guns. That requires sellers of these kits to obtain a federal gun dealer’s license and add serial numbers to some parts before sale so that they can be traced back to their owners if they turn up at a crime scene. 

Legal experts say the challenge is part of a broader conservative legal movement to limit the scope and scale of the federal government’s powers, and it is one of at least four cases in front of the justices that could have major ramifications for how guns are regulated in the United States. 

John Donohue, a Stanford law professor and gun policy expert, said the ghost gun rule has gone a long way toward curtailing the illicit use of unserialized weapons, but he worries the justices will determine that the ATF overstepped its authority. 

“As a matter of policy, I think it’s an unassailable, correct policy,” Donohue said about the rule. “The only question is whether it has been done in a way that allows the Supreme Court to throw a monkey wrench in the process.”

The Supreme Court is expected to hear arguments in the case in the fall.