Racial violence is often set off by the most superficial of trip wires: an isolated arrest, a rumor of police brutality, the temperature climbing above 100°. But rarely has a racial conflict seemed quite so random and inexplicable as the sudden savagery last week in Baton Rouge, where blacks clashed with police in a battle that left two policemen and two blacks dead and another 31 people injured.
Baton Rouge (pop. 166,000), the capital of Louisiana, is an anomaly, a throwback to an earlier South in which black complaints were bitter but rarely voiced. Though blacks are 28% of the population,...