LOS ANGELES - This city is just like the rest of the state - only more so. The powerful economic and social currents that have dramatically affected California during the last generation have utterly transformed its largest city.

What was Los Angeles no longer is, but no one knows what it will become - or even whether it will continue to exist in its present form. Its once-dominant power structure has been shattered by time and demography - leaving a deep civic vacuum - its economy has transmogrified, and some of its regional enclaves have been seeking independence.

The think-big, anything-is-possible attitude that once distinguished Los Angeles - the expropriation of water from a remote Northern California valley and the 1984 Olympics are two disparate examples - has given way to a small-beer politics. Economic and cultural interest groups and political careerists squabble over pieces of the political pie but lack a broader vision of the city's future.

Lawyer-businessman Richard Riordan tried to recapture Los Angeles' old civic vigor during his mayoralty, but it was an uphill struggle against prevailing economic and social forces, and the city's more pedestrian reality was expressed in the election of James Hahn as Riordan's successor three years ago.

When Hahn, a careerist who had ploddingly climbed the political ladder, defeated former Assembly Speaker Antonio Villaraigosa in 2001, it was a setback not only for the city's burgeoning Latino population but a defeat for the labor unions that have become the closest thing Los Angeles has to a political power center. Hahn won largely on his appeal to voters in the relatively conservative San Fernando Valley, implying that a Villaraigosa win would be a victory for the extreme left.

Hahn and his mayoral reign have been likened, not without cause, to Gray Davis and his governorship, which was cut short last year in a historic recall. Hahn, like Davis, is a charisma-challenged political lifer who has evinced little interest in anything beyond mundane matters of the moment. And, like Davis, Hahn's reign has been marked by the appearance of pay-to-play relationships with campaign contributors. Federal and local prosecutors are investigating allegations that contractors seeking city business were compelled to cough up political contributions. Hahn is clearly on the defensive and although the election that will decide his fate is a year away, his position is so weak that challengers are already lining up.

State Sen. Richard Alarcón, D-Sun Valley, is a candidate, and Villaraigosa, now a city councilman, may run again. City Councilman Bernard Parks, a former police chief who had a very nasty dust-up with Hahn with racial overtones (Parks is African American), may run as well. But potentially the most formidable challenger is former Assembly Speaker Bob Hertzberg, who formally declared himself last week.

Hertzberg, whose penchant for grabbing everyone in arm's length earned him the nickname "Hugsberg," is a double-barreled threat to Hahn. As a longtime San Fernando Valley political figure, he could cut into Hahn's voter base; although he did not endorse the unsuccessful drive by Valley leaders to secede from Los Angeles, he was sympathetic to their underlying grievances. And as an adviser to Gov. Arnold Schwarzenegger, he is evoking the spirit that ended Davis' career.

"My approach, just like the governor's, is bringing energy and action and a transformational nature to the campaign," Hertzberg said as he declared his candidacy. He criticized Hahn for lacking "the energy level and the interest and the imagination and the creativity," and pledged to "recapture (the) spirit of imagination - the big ideas and the big dreams that make our city great."

Schwarzenegger probably won't formally endorse Hertzberg, but the ties are unmistakable and nothing prevents Hertzberg from exploiting them. Whether Hertzberg or any of the other hopefuls emerges as the one-on-one challenger to Hahn, it's clear that the lackluster mayor is in trouble. The investigations of his administration are likely to continue for months, keeping him on the defensive, and the specific dissatisfactions among the city's many economic, cultural and geographic factions could merge synergistically.