LOS ANGELES (AP) - California's 33rd Congressional District is hard-core Democrat.
Ethnically diverse, cutting a swath from Hollywood through the city's historic black heartland, it's so thick with Democrats that John Kerry won 83 percent of the vote during the 2004 presidential election. Republicans didn't even bother to field a candidate in the last U.S. House race.
So why would Rudy Giuliani and Mitt Romney be interested in voters here?
In a twist on political logic, heavily Democratic patches in California are being fiercely contested by some Republican presidential candidates because of a change in state election rules.
For the first time in a contested race, the California GOP will distribute delegates based on the winner in each of the state's congressional districts, rather than to the candidate who piles up the most votes statewide.
The move has upended conventional campaign strategy, turning the Feb. 5 Republican primary into a chessboard of 53 separate contests, each with a prize of three delegates. To win the GOP presidential nomination, a candidate must secure 1,191 delegates in elections across the country.
Because only registered Republicans can vote in California's GOP presidential primary, there's temptation to pursue Democratic-leaning districts. A Republican candidate has to sway a relatively small number of voters to win.
A Democratic stronghold such as the 33rd District has about 30,000 registered Republicans. That's a fraction of the number in bedrock GOP territory such as the largely rural 22nd District in Kern, San Luis Obispo and Los Angeles counties, which has 165,000 Republicans.
In a crowded field with moderate turnout, a candidate could win the 33rd and claim its delegates with a few thousand votes, a number smaller than would be needed to win many city council races.
"It's a little like jujitsu. With the right application of a little amount of force, you could prevail," said Republican National Committee treasurer Tim Morgan.
"It changes the whole formula," said Republican pollster Steve Kinney, who is backing Arizona Sen. John McCain. "You can end up with far less votes overall and have most of the delegates."
Simple economics are at work, too. In a race where dollars are tight - there are more than 20 presidential contests on Feb. 5 - it costs a GOP campaign less to contact voters in a Democratic district, where Republican registration is slim.
Another likely target: the San Francisco district of House Speaker Nancy Pelosi, D-Calif., where fewer than one in 10 voters is registered as a Republican.
Giuliani, the former mayor of heavily Democratic New York City, could have an advantage in urban areas, given his left-leaning record on abortion, gay rights and gun control. California's coastal counties tend to be more liberal, while inland counties are more conservative.
"There are districts where the mayor would naturally run strongly that are heavily Democratic," said Giuliani's state chairman, Bill Simon.
The interest in Democratic districts is an unintended consequence of a rule change that was designed to lure more candidates to each region of the state, as well as build up political organizations in each congressional district that could benefit the party overall.
But with the priority on Iowa, New Hampshire and other early presidential contests, the state has seen little campaigning by candidates. No Republican has run a TV ad in California's costly media markets. Some, short on money, are likely to rely solely on volunteers to generate turnout on Feb. 5.
McCain, for example, has begun to organize a California campaign but with an all-volunteer effort.
So far, only Giuliani and Romney have had the money to support significant grass-roots activity in California, such as running phone banks to contact voters.
The GOP race in California mirrors the national contest - it's wide open. But Morgan, of the Republican National Committee, and other party members already are debating whether the district-by-district division of delegates makes sense.
Meanwhile, the party is struggling to reverse a slide in registration that comes as an unwelcome sign in a presidential election year. Both major parties have been losing membership in California, while the fastest growing segment of the electorate has no party affiliation at all.
Independents account for nearly 20 percent of California's 15.5 million registered voters.
The last time a GOP candidate carried California in a presidential election was 1988, when George H.W. Bush was elected. There were 5.4 million Republican voters at the time, about 39 percent of the California electorate.
Republicans now make up about 33 percent of California voters, compared to 43 percent for Democrats. Between February and December last year, the GOP lost more than 170,000 registered voters in the state. The Democratic decline in that period was about 69,000 voters.