The U.S. Supreme Court decision requiring California to reduce overcrowding in its prisons has triggered an outcry from legislators and the criminal justice community about the possibility of thousands of dangerous felons being released to the streets before the end of their terms.

That’s not likely to happen.

But the decision has shone a spotlight on one of the fastest growing parts of the state budget at a time when Gov. Jerry Brown and lawmakers are trying to cut anywhere they can. And the opinion has the potential to reignite a decades-long debate over whether California can and should do more to reduce crime by ensuring that felons who leave prison are as prepared as possible to start new, law-abiding lives on the outside.

The state now spends more than $10 billion a year on prisons, about twice what it spends from the general fund for the University of California and the California State University systems combined.

That’s a remarkable turnaround in a fairly short time. Just 15 years ago, in the mid-1990s, California was spending more than twice as much on its universities as its prisons.

Why the change? Prison costs have risen steadily due to longer sentences, more inmates sent to prison, higher salaries for correctional officers and more money spent on health care, while in the universities the state has turned to students and their families to shoulder more and more of the cost of their education.

The high court decision this week upheld lower court rulings forcing California to improve conditions in the prisons, especially the medical care given inmates. While they will never get much sympathy from the public, inmates have the right to basic health care, the courts have found, because a prison sentence is not the same as a death sentence.

With dozens of inmates dying unnecessarily because of inadequate care, the courts found that the conditions amounted to cruel and unusual punishment, which is prohibited by the Constitution.

The question now is how to fix the problem. While the state must reduce its inmate population by 30,000 over the next two years, the order does not require a wholesale release of inmates who are behind bars now. Other measures, some long recommended by prison reformers and in place in other states, could reduce the number of inmates in prison without shortening the term of anyone who is already locked up.

Gov. Brown has already proposed that the state shift between 10,000 and 15,000 inmates per year to the counties along with the money to pay for incarcerating them. It costs more than $50,000 a year to keep an inmate in state prison, and roughly half as much to lock someone up for a year in a county jail.

Under Brown’s plan, the counties would take over supervision of non-violent felons sentenced to three years or less and parolees who are returned to prison, usually to serve less than a year.

But Brown’s prison proposal is part of a larger plan to transfer billions of dollars in services to local government. That plan hinges on the Legislature or the voters approving the extension of temporary taxes that are expiring this year. So far, lawmakers have not agreed to do that, or even to call an election at which voters could decide the issue.

Some in Sacramento have suggested that the court ruling could give new ammunition to supporters of the tax extensions if they go on the ballot, because voters will not want to risk seeing inmates released from prison. But polls have repeatedly shown that the prison system is the program voters want to cut first, and protect the least when it is time to reduce spending.

While there is general support among voters for funding public safety, broadly defined, Californians are unlikely to raise their own taxes if they believe the money is for improving conditions in the prisons or in local jails.

Another option, at least over the longer term, is to improve rehabilitation and the services offered to inmates on their way out of prison. This idea was one-half of a grand compromise struck in 2007 by then-Gov. Arnold Schwarzenegger and the two parties in the Legislature.

The Democrats wanted to improve substance abuse treatment, education, and job training and help inmates with mental health counseling, housing and job searches just before and after they were released. The Republicans wanted to build more prisons. The final deal allowed for both, but the rehabilitation programs have not been sustained, in part because the state ran out of money to pay for them.

If the state can reinvigorate that effort, it is possible California could see less crime and lower costs if at least a share of the thousands of inmates whose prison terms end every year remain crime-free. Currently, about 70 percent of them end up back in prison within three years, either for committing new crimes or for violating the conditions of their parole. By one estimate, if new programs could reduce the recidivism rate by just 10 percent, they would pay for themselves.

The Supreme Court decision might also prompt lawmakers to consider fundamental changes in the state’s sentencing laws. The last time Brown was governor, in the mid-1970s, he signed a law ending open-ended terms for most inmates and replacing them with what are known as determinant sentences. The idea was supported by conservatives who thought too many criminals were serving too short of terms and by liberals who thought the opposite.

But what has ensued is a patchwork of sentencing laws driven largely by the political passions of the moment. Anecdotal reports of particularly disturbing crimes have led lawmakers to pass measures lengthening the term for this crime or that, without much regard to how all the sentences fit together.

Legislators also limited the ability of inmates to earn shorter terms by showing remorse and evidence of rehabilitation. While they can reduce their sentences by working or going to school behind bars, these have become almost embedded in the original sentence itself. Without more subjective incentives, some experts believe, inmates have little reason to improve themselves, and this makes it more likely that they will re-offend when they leave prison, as almost all of them eventually do.

A bipartisan task force led by former Gov. George Deukmejian, who drove the state’s prison building boom in the 1980s, recommended that the state establish a sentencing commission to create a new, more flexible system for locking up felons and releasing them. The hope was that a more rational set of sentencing laws would save money and reduce crime. But the Legislature was reluctant to create such a body, and Schwarzenegger never pushed them very hard to do so.

Since then, the state has careened toward what has seemed like an inevitable collision with the Supreme Court, delaying but not preventing the eventual day of reckoning.

Now that day has come, and stalling tactics, court motions and half-measures will no longer work. It remains to be seen what California will do instead.