Earlier this year the Supreme Court ruled that California prisons were in such bad shape they violated the 8th amendment prohibiting cruel and unusual punishment. The reason? Overcrowding. California must to reduce its prison population by 30,000, according to the ruling. Overcrowding is a perennial issue in US prisons in no small part because the recidivism rate is remarkably high. In 1994 the largest study of prisoner recidivism ever done in the U.S. showed that, of nearly 300,000 adult prisoners who were released in fifteen different states, 67.5 percent were re-arrested within three years.