The United States has been on a binge of imprisonment for the past four decades. Jail and prison rates quadrupled during that time. There is now a growing consensus that this has become a serious social and economic blunder. Prison does not improve people, and states can no longer afford the costs of mass incarceration. But what to do? Once we have locked up millions of people—with an entire criminal justice system oriented toward this misguided project—how can it be reversed? Promising pathways are being implemented and tested through the Smart Decarceration Intiative.