The US Court of Appeals for the Ninth Circuit agreed to re-hear the court’s 2023 three-judge panel decision Thursday which struck down a ban on butterfly knives in Hawaii.

Chief Judge Mary Murguia vacated the panel’s previous decision setting up another test for the scope of the Supreme Court’s 2022 ruling in New York State Rifle & Pistol Association, Inc. v. Bruen, the authority which the panel cited to strike the ban down.

Butterfly knives, also known as balisongs, are an easily opened type of pocket knife with two handles. They have been banned in Hawaii for 30 years and are subject to restrictions in numerous states as well as outright banned in many countries around the world. The case challenging the ban began in 2019 when two Hawaii men sued, arguing the restrictions were unconstitutional prohibitions on their rights to use the knives in self-defense.

A summary from the 2023 panel decision said that the knives were “bladed weapons [that] facially constitute arms within the meaning of the Second Amendment” and continued that “Hawaii had failed to prove that [the ban] was consistent with this Nation’s historical tradition of regulating weapons.” The state argued in its petition for a rehearing that the panel had misapplied Bruen to bladed weapons and that the court should have asked whether butterfly knives were commonly used for self-defense.

Bruen requires that any regulation of “firearms” be within the history and tradition of American weapons regulation. The decision of the case set off a firestorm of criticism for the new approach to Second Amendment constitutional issues and resulted in lower court cases ruling on the constitutionality of state laws governing everything from assault weapons to ammunition background checks.