The U.S. Supreme Court on Monday ordered two internet sellers of gun parts to comply with the Biden administration’s regulations aimed at blocking ghost guns.

The Supreme Court voted 5-4 on Tuesday to allow the Biden administration’s regulations on ghost guns to go into effect. Conservative Justices John Roberts and Amy Coney Barrett joined the three liberal justices in voting to uphold the enforcement against ghost guns.

The justices lifted U.S. District Judge Reed O’Connor injunction which barred enforcement of a 2022 federal regulation against Blackhawk Manufacturing and Defense Distributed.

The rule was issued by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) to target ghost guns, which can be made from kits at home. 

It bans “buy build shoot” kits that individuals can get online or at a store without a background check or the usual serial numbers required by the federal government. The kits can be quickly assembled into a working firearm.

The regulations changed the definition of a firearm under federal law to include unfinished parts, such as the frame of a handgun or the receiver of a long gun, so they can be tracked more easily. The requirement applies regardless of how the firearm was made, including the ghost guns made from kits. Sellers under the rule also must run background checks on purchasers prior to a sale.


However, in July, O’Connor invalidated the rule, saying that the Biden administration exceeded its authority under the Gun Control Act. 

The congressional definition of a firearm “does not cover weapon parts, or aggregations of weapon parts, regardless of whether the parts may be readily assembled into something that may fire a projectile,” the judge concluded.

In August, the administration halted O’Connor’s decision to block the regulation, reinstating the rule during the appeal proceeds.

The administration said O’Connor’s decision to grant an injunction favoring ghost gun kit makers despite the prior intervention by the justices “openly flouted” the Supreme Court’s authority.

The Biden administration argued the rule is necessary to respond to rising numbers of untraceable guns.

The Justice Department had told the court that local law enforcement agencies seized more than 19,000 ghost guns at crime scenes in 2021, a more than tenfold increase in just five years.

“The public-safety interests in reversing the flow of ghost guns to dangerous and otherwise prohibited persons easily outweighs the minor costs that respondents will incur,” Solicitor General Elizabeth Prelogar, the administration’s top Supreme Court lawyer, wrote in a court filing.

Plaintiffs including the parts manufacturers, various gun owners and two gun rights groups – the Firearms Policy Coalition and Second Amendment Foundation – filed suit to block the ghost guns rule in federal court in Texas

The regulation will be in effect while the administration appeals the judge’s ruling to the 5th U.S. Circuit Court of Appeals in New Orleans — and potentially the Supreme Court.

Reuters and the Associated Press contributed to this report.