On Monday the U.S. Supreme Court ordered California to release more than 30,000 people from its state prisons because of dangerous overcrowding. The Brown v. Plata decisioninterprets the federal Prison Litigation Reform Act so as to validate the prison population reduction order made by a three-judge federal panel overseeing health care and mental health care in California prisons. In 2009, that panel ordered the state to reduce the prison population to 110,000—137.5 percent of its design capacity of 80,000—over two years. The population is currently over 140,000 and was recently as high as 160,000.

Federal courts have monitored the California prisons for more than a decade because of their failure to provide adequate medical and mental health care, primarily due to overcrowded conditions. These conditions have continued to deteriorate 12 years after the first lawsuit was filed in this case and despite 70 court orders for remedies. The Supreme Court concluded Monday that the inadequate medical and mental health care constituted a violation of the Eighth Amendment’s prohibition against cruel and unusual punishment.

In a rare action, the Court included three striking photographs—including one of cages for people waiting for mental health crisis beds—to demonstrate the overcrowding. The Court found that overcrowding prevents the provision of adequate medical and mental health care, noting that suicide rates in the state’s prisons have been 80 percent higher than the average for inmates nationwide. A lower court in the case said it was “an uncontested fact” that “an inmate in one of California’s prisons needlessly dies every six or seven days due to constitutional deficiencies.” In his majority opinion, Justice Kennedy wrote that “[a] prison that deprives prisoners of basic sustenance, including adequate medical care, is incompatible with the concept of human dignity and has no place in civilized society.”

This decision and California’s response to it will have an immense impact on the medical and mental health care of people in prison, those on parole, and local jail populations. The impact on local governments will surely be significant as the state determines how to comply with the order when building new prisons is not an option. The Supreme Court’s decision will put more pressure on counties that are already struggling with overcrowded jails and overburdened criminal justice systems. Governor Jerry Brown signed legislation in April (Assembly Bill 109) to shift approximately 32,000 people convicted of low-level offenses to county jails and other facilities by 2013. Its $302 million budget has not been funded.

The rest of the nation will watch to see whether California will use this as a new opportunity to reexamine its policies of incarceration for technical parole and probation violations and minor, nonviolent offenses and to reserve its limited and costly jail and prison space for people who truly pose a threat to society.