In the case of United States v. Thompson/Center Arms Company, 1991, the Supreme Court was tasked with determining whether a gun kit that could be assembled into either a rifle or pistol should be classified as a short-barreled rifle under the National Firearms Act (NFA). The NFA imposes strict regulations and taxes on certain types of firearms including short-barreled rifles. Thompson/Center Arms Company argued that their product was not subject to these rules because it could also be assembled into a legal firearm - in this case, a pistol. The government disagreed stating that since one possible configuration was illegal under NFA, then all configurations were illegal. In its decision, the Supreme Court sided with Thompson/Center Arms Co., ruling that unless an item is specifically intended to only function as an illegal weapon (in this instance being used solely as a short-barreled rifle), it cannot fall within those restrictions imposed by NFA.

In the dissenting opinion for United States v. Thompson/Center Arms Company, Justice White argued that the Court's majority had misinterpreted the National Firearms Act (NFA). He believed that when a gun owner possesses all parts necessary to assemble either a rifle or a short-barreled weapon, they should be considered as possessing both types of firearms under NFA regulations. In this case, he contended that since Thompson/Center Arms sold kits containing all components needed to construct either type of firearm, it was irrelevant whether customers actually assembled them into illegal weapons; their mere potential for such assembly constituted possession in his view. Furthermore, he disagreed with the majority's reliance on lenity doctrine because ambiguity did not exist in statutory language and legislative intent was clear: Congress aimed at regulating any device readily convertible into an illicit firearm.