Kenosha, a city of 100,000 in Wisconsin’s southeastern corner, now confronts the question of when lethal force is justified in two different cases. One, the shooting of Jacob Blake by a police officer, I addressed yesterday. The other is the case of Kyle Rittenhouse, who is alleged to have killed two people and injured one during the civil unrest this week, and who has been charged with first-degree intentional homicide, reckless homicide, and other offenses.Rittenhouse is a 17-year-old from Antioch, Ill., about a half hour’s drive from Kenosha. Inexplicably, this underage police cadet from out of state wound up on the streets after curfew in a place where a riot was likely imminent, doing interviews with journalists and openly carrying an AR-15–style rifle.There can be no question that Rittenhouse and whatever adults were in charge of him made idiotic decisions. Minors should not stand guard at riots play-acting at being cops. But even people who knowingly put themselves in the wrong ...