The Supreme Court on Monday endorsed a court order requiring California to cut its prison population by tens of thousands of inmates to improve health care for those who remain behind bars.

The court said in a 5-4 decision that the reduction is "required by the Constitution" to correct longstanding violations of inmates' rights. The order mandates a prison population of no more than 110,000 inmates, still far above the system's designed capacity.

There are more than 142,000 inmates in the state's 33 adult prisons, meaning roughly 32,000 inmates will need to be transferred to other jurisdictions or released.

Justice Anthony Kennedy, a California native, wrote the majority opinion, in which he included photos of severe overcrowding. The court's four Democratic appointees joined with Kennedy.

"The violations have persisted for years. They remain uncorrected," Kennedy said.

Justice Antonin Scalia said in dissent that the court order is "perhaps the most radical injunction issued by a court in our nation's history."