Watching the Watchmen

American communities need robust law enforcement, and the vast majority of police officers are public servants performing dangerous work with dedication. The footage of Memphis police officers killing Tyre Nichols in early January, however, is all the more unbearable because Americans have seen the likes of it so many times before. Too many Americans today live in fear that they may suffer abuse or excessive force at the hands of police officers who are sworn to protect them.

Police officers killed 1,096 people in the United States last year, according...