Home to nearly one in eight Americans, California is a giant, diverse political landscape, enormously expensive for candidates yet offering the campaign's largest batch of delegates.
For years, candidates for presidential nominations mostly ignored California except to pick up checks in Hollywood or Silicon Valley. But the state assumed new importance this year by moving its primary from June to Feb. 5.
Catering to the state's burgeoning Hispanic population is just one of the necessities for campaigns this year.
Barack Obama and Hillary Rodham Clinton are fighting street by street for Hispanic votes amid the taco shops, Catholic churches and Spanish-language billboards in the neighborhoods east of downtown Los Angeles.
On TV, their campaigns air a stream of commercials in Spanish, targeting the state's fastest-growing population. The candidates' competition for endorsements has divided Hispanic politicians, and both have campaign offices in the area.
Messages shaped for Hispanics land in mailboxes: Clinton will "never stop working for the American dream," reads one printed in English and Spanish.
The lavishly funded Democrats are contesting everything, everywhere - celebrity hangouts like Malibu and Beverly Hills, Central Valley farming towns, liberal and high-tech enclaves around San Francisco Bay, in addition to Hispanic strongholds.
On the Republican side, Sen. John McCain held a 12-percentage-point lead in a late January poll, picked up an endorsement Thursday from celebrity Gov. Arnold Schwarzenegger and is looking to deliver a stinging defeat to rival Mitt Romney.
Clinton and Obama are vastly outspending Republicans in the state, considered a Democratic stronghold in November. McCain might battle Romney without airing a single TV commercial here - bucking conventional wisdom that the only way to reach voters in the nation's most populous state is on television screens. Romney does plan television ads in California, but it's not clear how extensive they will be.
Clinton, leading by 15 percentage points in a late January poll, is trying to summon the political magic that gave her husband commanding victories here in 1992 and 1996. She's counting on a big payoff from efforts to identify and lure absentee voters, who could account for more than half the ballots on Feb. 5.
Obama is pushing hard to contact independents - about 3 million of California's nearly 15.5 million registered voters - in hope of repeating the success with unaffiliated voters that powered his victory in Iowa.
"It's hard to beat the Clinton brand in California," said Democratic consultant Garry South, who is unaffiliated in the campaign. "Bill Clinton was here 70 times when he was president. He tended the state like it was his own personal vineyard. Not all that good will transfer to Hillary, but she will be hard to beat."
California's vote-by-mail numbers forced the campaigns to begin reaching out to early voters just after the holidays. Much of that advertising targeted the San Francisco Bay area, which has a high proportion of regular absentee voters.
California's GOP divvies up 170 delegates on Feb. 5 - three in each of the state's 53 congressional districts and a bonus of 11 to the statewide winner - with 1,191 needed to secure the party nomination.
For the first time, Republicans are awarding delegates to the winner in each congressional district. That has led GOP candidates to campaign in heavily Democratic districts, including San Francisco and Oakland, because a small number of Republicans there could deliver delegates with relatively little effort.
California Democrats will award 370 delegates of the 2,025 needed to secure the nomination. A Democrat can qualify for a delegate here by winning at least 15 percent of the vote in a congressional district.
With the collapse of Rudy Giuliani's presidential bid, Republican campaigns are notable for shoestring budgets in California.
Mitt Romney has sent out a sprinkle of mail ads and financed a small staff to organize phone banks to reach voters.
Aides say Romney is preparing to run between $2 million and $3 million for five days of ads in most media markets in California and on cable channels or local networks in other key Super Tuesday states. It wasn't clear how much of the total would be spent in California, where substantial one week television buy could cost $3 million or more.
Front-runner John McCain is running an insurgent-like campaign built on momentum and volunteer shoe-leather. For Super Tuesday, McCain's planning TV commercials on national cable channels and in key states, but so far he's invested nothing in California TV commercials - or radio or mailed fliers.
Mike Huckabee's operation has been low-key.
"I don't think anybody is going to have the money to do much between now and Tuesday," Republican analyst Allan Hoffenblum said.
Among Democrats, the fight for Hispanic votes is being matched in the black community.
Clinton counts basketball legend Ervin "Magic" Johnson among her supporters and holds an edge with other prominent endorsements, including Sen. Dianne Feinstein and the mayors of San Francisco and Los Angeles.
Obama's campaign acknowledges an uphill fight but is relying on a sprawling grass-roots operation to deliver delegates.
But he also has plenty of star power in his corner: Last summer, Oprah Winfrey helped him rake in $3 million during a fundraiser at her estate near Santa Barbara, as Stevie Wonder performed for a full house of A-list celebrities.
Whites are expected to make up the majority of California voters next week, 72 percent, followed by Hispanics at 14 percent, blacks with 6 percent and Asians, 5 percent, according to the Public Policy Institute of California.
Clinton and Obama held a polite face-to-face debate here Thursday before she set off across the state Friday and Saturday. Bill Clinton and daughter Chelsea, who attended Stanford University, also are expected to make appearances.
Obama headed to other states but will send Sen. Ted Kennedy and 2004 Democratic presidential nominee John Kerry to rally supporters throughout California.
