It's a timeworn cliché, but nevertheless true, that California is a place of almost limitless social mobility.

California's history, from its onset, has been punctuated with examples of men and women who came with nothing, or were born into poverty, and achieved power, fame and fortune. Even today, more than 150 years after California became a state, its upper crust is, at most, only a generation or two removed from humble beginnings.

That's certainly been true of the state's politicians, regardless of party. There is no permanent governing class in California, no dominance by inherited wealth, or office-by-birthright. There aren't even any political machines of enduring power. The mobility that marks other aspects of California society is evident in the roll of those who rose to power and fame from minuscule beginnings - Ronald Reagan, Willie Brown, Arnold Schwarzenegger and Jesse Unruh. And on Monday, Fabian Núñez, who helped his immigrant father tend the gardens of the wealthy three decades ago, joined the ranks of those politicians as the speaker of the state Assembly.

Dozens of family members, including his proud parents, watched as Núñez was sworn in as the Assembly's 66th speaker. Núñez defeated a couple of rivals in months of internal gamesmanship among Democrats, who opted for a first-termer to give them a potential four years of leadership stability after several rounds of two-year speakerships - one of the side effects of legislative term limits. Assembly Republicans have done the same, electing first-termer Kevin McCarthy as their leader.

The Assembly speakership is a shadow of what it was during the heyday of Unruh and Brown, the self-proclaimed "Ayatollah of the Legislature." Not only are speakership reigns much shorter, but term limits and incumbent-friendly districts have reduced the speaker's political authority and, therefore, his (or her) ability to command. The speaker simply doesn't have as much control over members' political careers as the office once had, serving more as a facilitator than quasi-dictator.

That said, the post is still an influential one and with the governorship now in the hands of Republican Schwarzenegger, the speaker and his counterpart in the Senate, the president pro tem, must represent the majority party in what loom as contentious dealings with Schwarzenegger on the deficit-plagued state budget, workers' compensation and other front-burner issues. In recent years, the Assembly speaker has taken a back seat to the larger-than-life Senate leader, John Burton, but he, too, is scheduled to step down later this year due to term limits. A quiet competition is under way among Senate Democrats over a successor.

Núñez offered the standard paeans to bipartisanship during his speech to the Assembly, promised to overhaul a dysfunctional Assembly committee structure, and pledged to cooperate with Schwarzenegger. The governor, himself a newcomer to the Capitol, quickly offered his personal congratulations to Núñez.

But changing speakers - or changing governors, for that matter - does not alter the essential conflicts that have paralyzed the Legislature for years and led to the current fiscal crisis. Republicans - including Schwarzenegger - still don't want to raise taxes, Democrats still don't want to cut health and social services spending, and the state is still tens of billions of dollars in debt.

Núñez, who segued into politics after a career as a labor union organizer and negotiator, brings those skills to the job, but also has some liabilities, including some resentment among the Assembly's moderate Democrats over what they regard as a slight in handing out positions, and shortcomings in the public aspects of the job. Núñez is essentially a backroom operator who's accustomed to secrecy, and in his first session with reporters was noncommittal on virtually every issue - even on whether he wanted to raise taxes.

The new speaker also faces one more problem: While Democrats are in no immediate danger of losing control of the Assembly, they lost two seats that they had expected to win in 2002, and as many as six of their seats are in contention this year. Núñez's tenure could be a brief one if his party drops several more seats in this year's elections.