American sentencing laws are rigid, harsh, and often unjust. Mass incarceration is a tragedy and a national embarrassment. Laws enacted in the 1980s and 1990s that mandated lengthy prison terms are the primary causes. The challenges are to undo mass incarceration, repeal or fundamentally overhaul the laws that caused it, and rebuild American sentencing systems. American legislators have not yet seriously addressed the subject. Hundreds of minor changes have recently been enacted, but they nibble at the edges-creating narrow exceptions to harsh laws for first offenders, narrowing criteria for probation and parole revocation, and establishing new treatment and "reentry" programs. These changes are important to individuals they affect but will not reverse mass incarceration or prevent individual injustices. Meaningful change will occur only when the mandatory minimum, three-strikes, life without parole, truth in sentencing, and comparable laws that required prison terms of historically unprecedented severity are repealed and new laws authorizing the release of large numbers of current prisoners are enacted and implemented. Whether these things happen will determine whether mass incarceration and wholesale injustices are much different in 2025 than they were in 2017.