In this case, the court considered this issue: Did the ATF exceed its statutory authority in promulgating its Final Rule purporting to regulate so-called “ghost guns”?

The case was decided on March 26, 2025.

The Supreme Court held that the Gun Control Act of 1968 authorizes the ATF to regulate weapon parts kits and unfinished frames or receivers that can be readily converted into functional firearms. Justice Neil Gorsuch authored the 7-2 majority opinion of the Court.

Weapon parts kits qualify as “weapons” under the statute when they contain all necessary components to build a gun and their intended function is clear. Everyday language permits describing incomplete objects by their intended use, just as a disassembled rifle remains a “weapon.” The statute reinforces this understanding by treating starter guns as firearms even though they require modification. A kit like Polymer80’s “Buy Build Shoot,” which can be assembled in about 20 minutes using common tools, meets the law’s definition because it can be “readily converted” into a functioning firearm, just as a blocked-barrel starter gun qualifies when easily modified for live fire. While not all kits may fall under this definition, the statute clearly covers at least some, making a facial challenge to the rule invalid.

The definition of “frame or receiver” also includes partially complete versions that can be finished quickly with standard tools. Ordinary language and the statute’s serialization requirements support this reading, as identification numbers are required on unfinished frames and receivers. Law enforcement has long treated such components as regulated firearms, and even the challengers conceded that some unfinished frames fall within the law’s scope. While some objects may be too incomplete to qualify, the statute reaches at least those requiring only minimal work, making ATF’s rule facially consistent with the law. Concerns about unintended consequences under the National Firearms Act are misplaced, as the government disavowed any authority to classify AR-15 receivers as machine guns, and the doctrines of lenity and constitutional avoidance do not apply where the statute’s meaning is clear.

Justices Sonia Sotomayor, Brett Kavanaugh, and Ketanji Brown Jackson each joined the majority opinion and also wrote separate concurring opinions.

Justices Clarence Thomas and Samuel Alito each authored dissenting opinions.

The opinion is presented here in its entirety, but with citations omitted. If you appreciate this episode, please subscribe. Thank you.