California voters handed a decisive victory to Gov. Jerry Brown on Tuesday in his effort to reshape the state's criminal justice system, approving a ballot measure to offer a new chance at prison release for thousands of prisoners.

Proposition 57, the governor's plan to further shrink the state's prison population, was supported by almost two-thirds of voters in Tuesday night returns.

The ballot measure changes the state's prison and legal systems in three significant ways. The least controversial element will reverse a law approved by voters in 2000 that sent more juvenile defendants to adult courtrooms. Those young defendants will now only be charged as adults with a judge's approval.

Proposition 57's strongest support came from urban areas with a sizable number of Democratic voters. It was opposed by many law enforcement officers, survivors of fallen officers, and prosecutors.

The most controversial parts of Proposition 57 involve the prospect of parole for felons who have not been convicted of one of California's designated "violent" crimes, and the creation of new good-behavior credits that all state prisoners would be eligible to earn.

Brown and district attorneys clashed mightily over the ballot measure's assertion that new parole eligibility would be limited to "nonviolent felons." Prosecutors accused the governor of hiding the fact that  some prisoners convicted of brutal sexual assault crimes, for example, would be eligible for parole under Proposition 57, the Los Angeles Times reports.