In a per curiam decision, the Court held that the Supreme Judicial Court of Massachusetts’ ruling went against the precedent set in District of Columbia v. Heller (2008), which held that “the Second Amendment extends, prima facie, to all instruments that constitute bearable arms, even those that were not in existence at the time of the founding.” The Court then responded to the three arguments provided by the lower court.

First, the lower court argued that stun guns “were not in common use at the time of the Second Amendment’s enactment.” The Court responded that Heller clearly stated that the Second Amendment “extends . . . to . . . arms . . . that were not in existence at the time of the founding.” Second, the lower court argued that stun guns are “unusual” because they are “a thoroughly modern invention.” The Court responded that “[b]y equating ‘unusual’ with ‘in common use at the time of the Second Amendment’s enactment,’ the court’s second explanation is the same as the first; it is inconsistent with Heller for the same reason.” Lastly, the lower court used “a contemporary lens” and found “nothing in the record to suggest that [stun guns] are readily adaptable to use in the military.” The Court responded that Heller “rejected the proposition ‘that only those weapons useful in warfare are protected.’”

The Court concluded that the explanation from the lower court contradicted established precedent and vacated their judgment. The case was then remanded for further proceedings not inconsistent with the Court’s opinion.