The US Supreme Court on Monday agreed to hear an appeal of a decision that struck down an ATF final rule aimed at limiting ghost guns. Ghost guns are weapons parts kits that can be put together to create a firearm without having to register it.

The US Court of Appeals for the Fifth Circuit previously found that the final rule constitutes unlawful agency action because it “flouts clear statutory text and exceeds the legislatively imposed limits on agency authority in the name of public policy.” Thus, the court ruled that the final rule is “limitless” and that the Gun Control Act (GCA) does not allow the final rule.

In April 2022, the ATF issued the final rule, which changed the definition of “frame” and “receiver” to include split or multi-part receivers. The final rule stipulated that:

The terms ‘frame’ and ‘receiver’ shall include a partially complete, disassembled, or nonfunctional frame or receiver, including a frame or receiver parts kit, that is designed to or may readily be completed, assembled, restored, or otherwise converted to function as a frame or receiver, i.e., to house or provide a structure for the primary energized component of a handgun, breech blocking or sealing component of a projectile weapon other than a handgun.

The Biden administration appealed this holding to the US Supreme Court, arguing the provisions of the final rule “reflect the plain meaning of the relevant provisions of the [GCA] … the relevant part of the [Final] Rule reaches only weapon parts kits that may ‘readily … be completed, assembled, restored, or otherwise converted’ into a functional weapon.”

This is not the only litigation in the US over ghost guns. Last week, the Nevada Supreme Court upheld a 2021 state ban on ghost guns.