Mass incarceration is a term used by historians and sociologists to describe the substantial increase in the number of incarcerated people in United States’ prisons over the past forty years. The prison population of the United States dwarfs the prison populations of every other developed country in the world, including countries thought to be repressive like China and Russia. Since 1985, the number of people imprisoned in the United States has risen drastically. "Although the United States makes up only 5% of the world's population, it now accounts for one-quarter of the world's prisoners", most of whom are minorities, teenagers, the elderly, and women.Michelle Alexander describes mass incarceration as "the criminal justice system but also to the larger web of laws, rules, policies, and customs that control those labeled criminals both in and out of prison." The 13th amendment rendered slavery illegal with the exception of prisoners. After slavery, many laws were passed in order to target the black populations in America, such as the Jim Crow laws, which were one of the many tools used that allowed for the marginalization of black people and led to mass incarceration. For example, a grant was filed in 1995 that offered a monetary reward to prisons that increased their prison population. Gilda Graff theorizes that this has become the case because the people with the privilege and power to stop it are ashamed of slavery. Whether they are ashamed of profiting from slavery or coming from slaves, the shame obfuscates the problem.
Though the prison population of United States dwarfs that of other countries, there has been studies that show that some European countries following the steps of the United States like Portugal and Hungary. Like the United States these countries have followed the same trend with incarcerating large percentages of their minorities and communities of color. From the African American population in the United States, the Aboriginal in Australia or the Romany in Europe the communities of color are the ones suffering from these high incarceration rates.
According to historians, social scientists, and scholars, mass incarceration began in the 1960s and 1970s with a rise in “tough-on-crime” approaches to criminal justice and with deliberate policy choices that impose intentionally punitive sentences. This approach has increased both the numbers of people entering the criminal justice system and how long they remain under correctional control. Activists and academics against mass incarceration have argued for ending the "War on Drugs", eliminating racial disparities in criminal justice, ending the privatization of prisons, and advocating for alternatives to incarceration." Legislation that was originally passed to ease the burden of overcrowded prisons was warped by mass incarceration. Costello v. Wainwright attempted a solution to overcrowded prisons by allowing the state to build more prisons. With the changing political climate and "Law and Order" politicians, this legislation became precedent to continually build prisons and exacerbate the problem of mass incarceration instead of solving it.