Why are so many Americans behind bars?
14 July 2015 Last updated at 17:14 BST
More people are in prison in America than anywhere else in the world, driven in part by laws with heavy sentences for non-violent drug charges.
Drug policy has had a severe impact on African-Americans in the US, who make up the largest proportion of these sentences.
President Barack Obama wants to make the country's prison system fairer, and the high cost of keeping so many people in prison has attracted both Republicans and Democrats to the cause of sentencing reform.
Rajini Vaidyanathan looks at how the US prison population got to record levels.
Filmed and edited by Franz Strasser.