A gymnasium that was modified to house prisoners on December 10, 2010, at Chino State Prison — one of many California correctional institutions with a history of severe overcrowding. (Kevork Djansezian/Getty Images)

A gymnasium that was modified to house prisoners on December 10, 2010, at Chino State Prison — one of many California correctional institutions with a history of severe overcrowding. (Kevork Djansezian/Getty Images)

A gymnasium that was modified to house prisoners on December 10, 2010, at Chino State Prison — one of many California correctional institutions with a history of severe overcrowding. (Kevork Djansezian/Getty Images)