The historically unprecedented expansion of the American carceral system between roughly 1973 and 2008 — a period during which the number of people held in U.S. prisons and jails grew from about 360,000 to over 2.3 million, giving the United States the highest incarceration rate in the world by a substantial margin. Black Americans are imprisoned at roughly five times the rate of white Americans; the disparities for Latino, Indigenous, and poor Americans are also large. The term mass incarceration names not only the scale but the structural and racial pattern: a punishment regime that functions less like criminal law as ordinarily conceived and more like a system of social management.
The political construction of this system is the subject of a now-substantial literature. Michelle Alexander's The New Jim Crow (2010) made the influential argument that the post-1970s drug war and the criminal records it generated have served as a successor regime to formal Jim Crow segregation, perpetuating racial caste through nominally race-neutral law. James Forman Jr.'s Locking Up Our Own (2017) complicated the account by showing that Black political leadership in cities like Washington, D.C., often supported the punitive turn under conditions of constrained alternatives, asking for both more police and the social investments that were never delivered. Bryan Stevenson's Just Mercy (2014) and his Equal Justice Initiative trace the line directly from slavery and lynching through convict leasing to the contemporary carceral state. Isabel Wilkerson's Caste framework and Sasha Abramsky's reporting (Hard Time Blues, 2002; The American Way of Poverty, 2013) set the system in its larger context of inequality and political fear.
Decarceration has been a slow project. The U.S. prison population has fallen modestly from its 2008 peak; the underlying political and economic infrastructures that built it remain largely intact.