Under any criminal law, injustice can result if cops get the facts wrong. The Sanford, Fla., police, accused of buying a dubious self-defense tale after the Trayvon Martin shooting, will now come under searching scrutiny for that decision. Sanford’s mayor says his town is eager to stand corrected by the evidence as a fuller story emerges. So who’s left to disagree? Not the authors of Florida’s Stand Your Ground law, who told The Miami Herald that the law they sponsored applies only to cases of genuine self defense and won’t protect neighborhood-watcher George Zimmerman if critics of the Martin shooting are right about what he did that night.

The old “duty to retreat” rule made it hard to invoke self defense even if you had faced an immediate threat of assault: “you could have run away,” the state would argue, and conviction would follow. Among those who often lost out under that old rule were domestic violence victims who turned on their assailants; feminists pointed out that “you could have run away” may not work well when faced with a stalker or vengeful ex.

Despite doomful predictions from gun foes, concealed carry (now the dominant rule) and liberalized self-defense laws (adopted by half the states) haven’t touched off the great warned-of surge of gun violence. Yes, prosecutors may now need to take more care to marshal a show of actual evidence to counter claims of self defense. For those who value due process in criminal justice — a group that should emphatically include members of historically mistreated minorities — that should count as not a bug but a feature.