In a groundbreaking resolution, the Los Angeles Unified District school board voted Tuesday to ban suspensions for “willful defiance,” making it the first district in the state to do so. This decision will stop suspensions for a variety of misbehaviors—anything from mouthing off to teachers, eating food in the classroom, or violating the school dress code—which critics have maintained are too broad and arbitrarily enforced. Instead, starting next year, principals will install alternative disciplinary measures while students remain in school. The ban in LAUSD, the second largest school district in the country, marks a major shift from a zero-tolerance policy...