Police Department of the City of Chicago v. Mosley

A Chicago ordinance banned picketing within 150 feet of a school but exempted peaceful labor picketing; Earl Mosley (plaintiff), who had peacefully picketed a school to protest racial discrimination there, was threatened with arrest if he continued once the ordinance took effect. He sued, and the district court dismissed his First Amendment challenge, but the court of appeals reversed and found the ordinance unconstitutional.