The US Supreme Court is hearing arguments on Tuesday regarding whether a Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) regulation that requires gun parts sold for home assembly to have serial numbers is within the scope of a law that allows the federal government to impose background checks, record-keeping and serial number requirements on firearm sellers.

The court is considering whether the ATF can regulate ready to assemble weapons parts kits the same way it regulates guns, and whether the ATF can regulate partial gun frames.

ATF regulation 27 C.F.R. § 478.11 from 2022 includes “parts which can be readily converted into operational firearms” in its definition of firearms. This subjects guns that are sold for home assembly to the serial number requirements of the Gun Control Act 1968. Partial firearm frames are also subjected to regulation by the ATF under 27 C.F.R. § 478.12.

The present case was appealed from the Fifth Circuit Court of Appeals, which held that the ATF did not have the power to regulate gun kits, or partial frames under the 1968 Act. That being said, the Supreme Court blocked the decision of the lower court from being enforced in 2023, leaving the ATF regulations in full effect while the case is being appealed.

This case will depend on how the court chooses to interpret the language of the statute. Pete Patterson, a representative of the kit sellers who are challenging the regulation take a literal approach to interpreting the law, arguing that “a kit of parts is not a weapon”. On the other hand, Southern Methodist University law professor Eric Ruben takes an approach that focuses on the intended purpose of the 1968 Act, rather than strictly looking at the wording. He claims that the law was meant to be “broad and flexible”.