Law-enforcement agencies in the U.S. have broad power to seize a person’s property, auction it off, and keep the proceeds—without ever having to charge the owner with a crime. Although this practice, known as civil-asset forfeiture, has replenished police-department coffers for years, it is under more scrutiny than ever. Later this month, a bipartisan coalition in California’s legislature will move to curtail the practice in the Golden State. This effort should encourage Congress and other states to rein in this threat to personal property and individual liberty.

The...