California has begun auditioning leading men to fill a strangely unique role — a part that has left Arnold Schwarzenegger frequently resembling a 98-pound weakling.

Los Angeles Mayor Antonio Villaraigosa announced with considerable fanfare Monday that he would not run for governor — clearly a selfless act, if by “selfless” you mean sparing the nation’s second-largest city from the prospect of watching its elected leader experience an embarrassing primary defeat.

“I feel compelled to complete what I started out to do. … I can’t leave this city in the middle of a crisis,” Villaraigosa told CNN’s Wolf Blitzer, during an interview that proved vacuous even by Blitzer’s standards. Then again, Blitzer seemed like a safe choice on multiple levels, given the mayor’s habit of subsequently dating female TV interviewers.

So the announced contenders to replace Schwarzenegger are San Francisco mayor Gavin Newsom, 41, and attorney general Jerry Brown, who at 71 — after an earlier gubernatorial stint that concluded in 1983 — is looking for a rerun. (L.A.’s mayor, 56, would have symmetrically split the age gap between them.)

The future thus remains murky regarding an heir to Schwarzenegger, who was swept into office in 2003 amid a wave of public anger that saw his predecessor, the aptly named Gray Davis, ousted in a recall election. Yet while having a movie star has been a boon to those who relish stereotyping California and latenight comedians (as well as a curse to headline writers trying to fit “Schwarzenegger” into anything but a banner), his frustrating tenure has only reinforced the impression that the state is virtually ungovernable.

OF COURSE, Schwarzenegger went to Sacramento without much to recommend him other than a mantra that Californians are over-taxed — from the time they wake up and go to the bathroom until they go to bed, and then their dreams are taxed, blah blah blah. He punctuated his speeches with movie one-liners, did much of his campaigning on “The Tonight Show” and kept chatting about his own undeniably impressive pumping-to-prominence story. People ate it up, for awhile.

Then the governing part came in, and Schwarzenegger discovered that his constituents are more than a little two-faced. Sure, they hate taxes, but they also dislike being deprived of crucial services. So they want the benefits of government without actually paying for them.

Moreover, the requirement of a two-thirds majority to pass a budget makes compromise difficult — and in movie terms, artificially elevates the importance of bit players who might otherwise be ignored. Forced to share the limelight with his not-so-supportive supporting cast, the governor tried bypassing the legislature by going directly to the people, but the charm offensive had by then already grown thin.

When Schwarzenegger sought to strike compromises with the Democrats, he was labeled a RINO — Republican in Name Only — and vilified by the talkradio yahoos that previously brayed for Davis’ head.

SO WHAT DOES California’s latest actor-turned-politician have to show for his trouble? Not much, really, other than having his private life intruded upon in a way that seldom occurs at press junkets. After the Los Angeles Times investigated allegations regarding Schwarzenegger’s interactions with women, candidate Schwarzenegger admitted that he had at times “behaved badly,” been on “rowdy movie sets” and “offended people,” for which he apologized. Conservatives were understandably outraged — at the newspaper for seeking to impugn a Republican with such scurrilous allegations.

Meanwhile, Schwarzenegger’s acting hiatus came at a bad time for Warner Bros. Without him, the latest extensions of the “Terminator” franchise — “Terminator Salvation” and the superior Fox TV series “The Sarah Connor Chronicles” — both fell short of commercial expectations. Apparently, a property associated with the actor for 25 years lost something in translation without Mr. “I’ll be back” to anchor it.

So what now for California? Painful choices loom about taxes and budget cuts, as well as talk of overhauling a system that Villaraigosa rightfully called “fundamentally flawed” and “broken.” Any such fix, however, will almost certainly arrive too late to let Schwarzenegger roar off in triumph.

Then again, maybe we cast the wrong guy all along. Because as traditional hero quests go, rescuing California looks like a job for Superman.