The United States incarcerates people at a higher rate than any other country in the world. Large increases in the U.S. incarceration rate over the past three decades are costly in terms of explicit expenditures, as well as in terms of the collateral social consequences for those who serve time and for the communities from which they come. Increases in incarceration rates do reduce crime. At the nation’s current high incarceration rates, however, the crime-fighting effects of incarceration are much smaller than they were when the incarceration rate was much lower. Based on recent research and the experiences of several states, we believe that there is substantial room to reduce incarceration rates in the United States without adversely impacting crime rates. The policy choices that have increased the nation’s incarceration rate since the early 1990s have been particularly ineffective at combating crime. We argue that states should reevaluate their policy choices and reduce the scope and severity of several of the sentencing practices that they have implemented over the past twenty-five or thirty years. We propose that states introduce a greater degree of discretion into their sentencing and parole practices through two specific reforms: (1) a reduction in the scope and severity of truth-in-sentencing laws that mandate that inmates serve minimum proportions of their sentences, and (2) a reworking and, in many instances, abandonment of mandatory minimum sentences. We also propose that states create incentives for localities to limit their use of state prison systems.