Tess Vigeland: Tomorrow, California will detail its plan to reduce overcrowding in prisons. It has to be done because the U.S. Supreme Court says prison conditions in this state are inhumane. California has the biggest prison industry in the world, but it's not adequate for the number of inmates, and the state can't afford it.

As Marketplace's Jeff Tyler reports, correcting the corrections system is easier on paper than in reality.

Jeff Tyler: Over the last decade, spending on California prisons has jumped from 5 percent of the state's general fund budget to around 11 percent.

Mark Leno: This is unsustainable. Without significant reform, we could see our state general fund spending 15 percent, 20 percent on corrections.

That's state Sen. Mark Leno. He wrote a state law that would release prison inmates on medical parole. But only those who are permanently incapacitated and no longer pose a risk to the public.

Leno: In many cases, these individuals are comatose. This is a huge waste of tax dollars at a time when we don't have a penny to waste.

Leno says California could save millions of dollars. But the parole board recently rejected the first application for medical parole, even though the prisoner could not move anything below his neck.

Leno: If we can't put on medical parole a quadriplegic, I'm wondering who we can.

Of course, medical parole isn't the only path to reform. The state could save money by putting more people on probation rather than locking them up.

Barry Krisberg with UC Berkeley's Law School says housing an inmate in prison costs about $50,000 a year.

Barry Krisberg: Putting that same person on probation -- even intensive probation -- would be $12,000. So you're saving an extraordinary amount of money by managing the non-dangerous people in probation.

Krisberg says overcrowding could also be reduced by shifting some inmates from state prisons to county jails.

Krisberg: We could divert low-risk, non-violent, non-sex offenders to the counties, which is what Gov. Brown is proposing. And was done interestingly by both his father, Gov. Pat Brown, and by Ronald Reagan.

Many of the state-prison inmates would be transferred to county jails.

Steve Whitmore, spokesman for the Los Angeles County Sheriff's Department, supports this approach in principle.

Steve Whitmore: We have the capacity if we get the funding. If the funding is not approved, L.A. County cannot provide the necessary beds for the transfer of these inmates.

There's the rub. California Gov. Jerry Brown has put forward something called the "realignment plan." He says it could reduce prison overcrowding and cut expenses. The realignment plan would give more money and discretion to the counties. The governor wants to pay for his plan by extending taxes scheduled to expire.

That idea is anathema to Republicans like state Sen. Bob Huff.

Bob Huff: Raising taxes at this time -- or frankly any time -- would be the wrong move. We're already one of the highest taxed states in the nation.

Sen. Huff warns of a public safety threat if thousands of inmates are released. He thinks the solution to the prison overcrowding problem is more prisons.

Huff: The Democrats in Sacramento have blocked construction of prison beds, even though we approved a $9 bond sometime back to do just that.

But law professor Barry Krisberg says building new prisons is not only expensive, it also takes years -- so it would not alleviate the current overcrowding.

Krisberg: The federal courts would be screaming and hollering and holding us in contempt if the solution was just new construction.

California officials submit their plan to reduce prison overcrowding tomorrow. Once it's approved, California will have two years to put the plan into action, giving the state time to get its runaway prison system under control.

In Los Angeles, I'm Jeff Tyler for Marketplace.