On March 26, 2019, every American who owned a bump stock, a rifle accessory that facilitates rapid firing, was suddenly guilty of a federal felony punishable by up to 10 years in prison. That did not happen because a new law took effect; it happened because federal regulators reinterpreted an existing law to mean something they had long said it did not mean.
On Wednesday, the U.S. Supreme Court considered the question of whether those bureaucrats had the authority to do that. The case, Garland v. Cargill, turns on whether bump stocks are prohibited under the "best reading" of the federal statute covering machine guns. While several justices were clearly inclined to take that view, several others had reservations.
