Some 250 convicted killers went to court in California last year claiming former Gov. Arnold Schwarzenegger put politics ahead of the law when he blocked their parole - and based on other recent cases, scores of them are expected to prevail.

The action, which costs taxpayers million of dollars in legal fees and other expenses, stems from an unusual twist in state law: California has a professional parole board charged with deciding on inmates' release dates, but also gives the governor the power to overrule the board's decisions. Only four other states allow a similar tension.

Critics of the system, which was approved by voters in 1988, say it has politicized the length of prison terms and wastes money on lawsuits, extra prison expenses and costly parole hearings.

The politics of prison sentences became a flash point earlier this month when Schwarzenegger reduced by more than half the 16-year term of Esteban Nuñez, the son of former Assembly Speaker Fabian Nuñez. The governor said the younger Nuñez had been part of a group that killed a college student, but he did not deliver the fatal blow.

That decision was in stark contrast with 29 other cases in 2009 in which Schwarzenegger overturned decisions by his parole board to free inmates who had served lengthy sentences for their involvement in similar crimes, a Times review of state records showed.

Critics of California's parole system have called for the fate of inmates to be taken out of politicians' hands and left up to professionals. And courts have been taking issue with the way successive governors have used their authority.

"The governor could issue a blanket decision declining to review the board," said USC law professor Heidi Rummel, an advocate for prisoner rights, who noted that the board members are appointed by the governor's office. "That would alleviate the political pressure to look tough on crime."

Elizabeth Ashford, spokeswoman for Gov. Jerry Brown, would not say how Brown will approach such decisions. "We're two weeks into the administration, it's very early to be commenting on these kinds of things."

The 1988 ballot measure, approved the same year that Republican presidential nominee George H. W. Bush used an ad featuring furloughed killer Willie Horton to devastating effect against Democratic rival Michael Dukakis, gave California governors the right to reverse parole orders for convicted murderers. Only Maryland, Hawaii, Louisiana and Oklahoma have given their governors similar power, said Debbie Mukamal, a researcher at Stanford Law School.

Since the ballot measure passed, governors have used their power aggressively. Democrat Gray Davis allowed only nine of 371 murderers paroled during his tenure to go free. Schwarzenegger overturned his 17-member parole board, each of whom makes $100,000 per year, in about 60% of cases.

Experts say inmates didn't have much success appealing those decisions until a 2008 state Supreme Court case overturned Schwarzenegger's refusal to release a model inmate who had served nearly 24 years.

The court said Schwarzenegger had failed to show that then-61-year-old Sandra Day Lawrence, who killed her lover's wife in a jealous rage in 1971, still represented an unreasonable risk to public safety.

Lawrence, who had had four separate parole orders revoked by three governors, had shown "overwhelming" evidence that she was rehabilitated and suitable for parole, the court said.

The governor still has the right to overturn a parole board decision if he can show that something in the inmate's record suggests a pattern of dangerous behavior, according to the state Supreme Court.

More than half of Rummel's clients have prevailed in cases decided since the court set the new standard. "It really changed everything," she said.

Michelle Quinn, a spokeswoman for Atty. Gen. Kamala Harris, said she couldn't estimate how much defending the inmates' court challenges cost the state because "the AG's office doesn't keep track of the cost of individual criminal cases."

But in addition to the 250 new cases brought by inmates last year, the attorney general also appealed 50 cases in which state courts had ruled in favor of releasing inmates after the governor revoked their parole, Quinn said.

In another court challenge resulting from a Schwarzenegger sentencing decision, the parents of Luis Santos, the 22-year-old killed in the attack by Esteban Nuñez and three friends, said they will file a lawsuit in Sacramento Superior Court on Thursday claiming the former governor violated California's Victim's Bill of Rights when he commuted Nuñez's sentence.

Fred Santos, the victim's father, has decried the commutation as a favor to Fabian Nuñez, who as Assembly speaker was often a political ally of Schwarzenegger's.

Lawrence, now free and offering motivational talks to help keep youths out of prison, said she was never surprised when governors decided not to risk their political future by setting her free. "They don't know me, they don't love me, I'm not related to them...so nobody is going to put their neck on the chopping block for me," Lawrence said.