ANN ARBOR, Mich. — A gun openly carried by a spectator at a school concert in 2015 has turned into a major legal case, as the Michigan Supreme Court considers whether the state’s public schools can trump the Legislature and adopt their own restrictions on firearms.

The case from Ann Arbor has been on the court’s docket for more than a year. But arguments set for Wednesday are getting extra attention in the wake of a Florida school shooting in February that killed 17.

There is no dispute that Michigan law bars people from possessing a gun inside a weapon-free school zone. But there’s a wrinkle: Someone with a concealed pistol permit can enter school property with a gun that is openly holstered.

It happened three years ago at a choir concert at Ann Arbor Pioneer High School, scaring teens, staff, and spectators. The school board responded by banning all guns, with exceptions for police.

‘‘If a student were to bring a gun into a school, that would be worthy of an expulsion,’’ said Jeanice Kerr Swift, superintendent of Ann Arbor schools. ‘‘So why would it be different for other folks? ’’

Associated Press