The changing face of one of Southern California's wealthiest counties helped Democrat Loretta Sanchez win an upset election to Congress 14 years ago, as Latinos arrived as a political force. Now, a rising tide of Vietnamese political clout has her fighting to hang onto her seat.

To the surprise of many voters in California's gritty, urban 47th District — which shares little with the affluent beachfront communities that give Orange County its fame — Sanchez recently injected the thorny issue of race into the campaign. Speaking on Spanish-language network Univision, she said "the Vietnamese and Republicans" were trying "to take this seat from us... and give it to this Van Tran who is very anti-immigrant and very anti-Hispanic" — words she later conceded were poorly chosen.

Vietnamese-American state Assemblyman Van Tran, Sanchez's first serious challenger, said he was offended by the remarks and called them a "racial rampage" against Vietnamese-Americans, who came to Southern California as refugees 35 years ago and built a bustling commercial hub in the heart of Orange County.

"You're seeing two emerging communities ... seeing themselves not as potential allies in these kinds of head-to-head races but as foes in a zero sum game and that becomes dangerous," said James Lai, a political science professor at Santa Clara University.

There is no other district with candidates hailing from two sizable ethnic communities in such a potentially close race, according to Democrat and Republican Congressional Campaign committees. Many contests pit a white against a minority candidate. A handful — like Louisiana's 2nd Congressional District __ have a race between two minority contenders but they rarely have support in two large ethnic constituencies.

For many years, Orange County was seen as a wealthy white suburb of Los Angeles. But the county — home to Disneyland — is now far more diverse thanks to growing Latino and Asian-American communities, and non-Hispanic whites make up less than half of the population.

The district — which includes Santa Ana, Garden Grove, Anaheim and Fullerton — is no stranger to ethnic controversy. In 1996, Sanchez's conservative predecessor Bob Dornan, known as "B-1 Bob" for his support of military programs and his bombastic personality, claimed many who cast a ballot for his opponent were ineligible to vote. A decade later, the Republican candidate for Sanchez's seat, Tan Nguyen, sent a Spanish-language mailer to Latino Democrats warning them immigrants could not vote.

Political experts said Sanchez's recent remarks may have been a calculated risk to drive Latinos to the polls in November.

While the majority of the district is Hispanic and Democrat, Latinos have a lower turnout rate than Vietnamese-Americans and Democratic candidates will likely be hurt this year by the anti-incumbent sentiment sweeping a nation wracked by the recession.

Sanchez, who will have former President Bill Clinton stump for her later this month, still has the advantage but acknowledges she is only two or three points ahead of Tran in polls in a district where more than two-thirds of residents are Latino and 15 percent are Asian.

About 47 percent of the district's voters are Democrats and 31 percent are Republicans.

"I don't know if they are going to come out to vote," Sanchez said of Latinos and Democrats. "And if they don't come out to vote, we won't win."

The big question is whether Vietnamese-Americans who have long cast a ballot for Sanchez — even though many are Republicans — will continue to support her or vote along ethnic lines.

Sanchez has championed key issues for the Vietnamese community, such as denouncing Vietnam's record of religious persecution. But political scientists say voters tend to pick candidates from their own ethnic background.

Tran was the first Vietnamese-American elected to a state Legislature in 2004 and is a beloved leader in the community. He has helped groom dozens of Vietnamese-Americans to run for local offices in Orange County.

Puffing on a Marlboro outside his Vietnamese restaurant in Santa Ana, Duke Nguyen said he supports Tran because he's Republican, and also because he's Vietnamese and can speak for the community.

"We are proud to have another Vietnamese in Congress," the 54-year old said.

But some political experts say the increased presence of Vietnamese elected officials may mean it could take more than just a Vietnamese surname to win votes. Especially since many Vietnamese-American officials, including Tran, now have a track record that voters can explore.

Tan Nguyen, a 38-year old real estate agent from Garden Grove, said he has backed Sanchez even though he's a Republican because she stands up to the communist government in Vietnam on human rights. And he isn't wavering this year.

"We don't have to vote for Vietnamese," said Nguyen, no relation to the previous congressional candidate. "We vote for the one who works for us, who helps us, who fights for us."

But the vote is not only up to the Vietnamese-American electorate. Experts say Latinos could determine the outcome of the race if they don't vote. And Sanchez could also see some votes siphoned off by independent Latina candidate Cecilia Iglesias.

That worries Democrat Maria Sanchez-Mendez, a longtime Sanchez supporter. The 40-year old college preparation adviser said she is voting for the incumbent because of her support for education and her down-to-earth demeanor.

"I am not going to just vote for someone because she has a Spanish surname," she said.

The candidates are also at odds over who will better represent immigrants in a district where nearly half of residents are foreign-born and more than three-quarters speak a language other than English.

Sanchez, born in California to Mexican immigrant parents, supports a plan to overhaul the country's immigration system. Tran said he represents immigrants through his personal experience as a refugee.

"We're not conceding any parts of the constituency," Tran said.