The U.S. Supreme Court will soon consider a petition that pits police against a leader of the Black Lives Matter movement in a dispute over the First Amendment rights of assembly, petition and speech.

But the case, Mckesson v. Doe, does not arise from the nationwide protests of recent weeks. Instead, it dates back to a 2016 protest in Baton Rouge, Louisiana, triggered by the death of Alton Sterling, an African American man shot and killed at close range by police responding to an anonymous 911 call. Among other themes, demonstrators chanted “Black Lives Matter” as they protested against the police conduct.