HANFORD, Calif. -- When Representative David Valadao came out in favor of a path to citizenship for millions of people living in the country illegally at an open forum this summer, the crowd erupted in applause, and young activists nearly knocked one another down as they rushed to embrace him.
Since then, Mr. Valadao, a freshman Republican, has become a bit of an unlikely celebrity among Latino farmworkers and their families in California's Central Valley, where immigration has shaped the agricultural industry for decades.
As the immigration debate simmers in Washington, California Republicans face a very different reality than a majority of their party colleagues, who elsewhere largely represent districts that are overwhelmingly white.
More than half of California's 15 Republican members of Congress have districts that are at least 30 percent Latino, making them potentially vulnerable to Democratic challenges and prime targets for those pushing for a path to citizenship. In Mr. Valadao's district, Latinos make up 70 percent of the population.
With Republicans all but relegated to a minority party in California -- Democrats hold every statewide elected office, maintain a large majority in the State Legislature and hold a vast majority of Congressional seats -- many here blame the party's decline on its stance on immigration.
"We're finally breaking out of denial," said Allan Hoffenblum, a longtime Republican consultant in state politics. "Until we solve our Latino problem, we're not going to be a viable state party, and it's hard to understand how that's possible without fixing immigration."
Mr. Valadao, the son of Portuguese immigrants, is one of a few Republicans in the state offering full-throated support for sweeping changes to the country's immigration laws. Representatives Jeff Denham and Devin Nunes, whose districts include northern stretches of the state's agricultural center, have said they would support some kind of legalization process for the nation's roughly 11 million illegal immigrants, the most divisive issue in the debate.
All of this has put pressure on Representative Kevin McCarthy, a Republican whose district is about one-third Latino and includes part of Bakersfield, a working-class, immigrant-heavy city that Mr. Valadao also represents. As the majority whip, the third-ranking leader of the Republican-controlled House, Mr. McCarthy is expected to play an important role in deciding which legislative proposals end up being voted on and which are squelched this fall.
In the past, Mr. McCarthy has called the immigration process broken, saying that the priority must be on securing borders and that he is opposed to an amnesty. Aides to the lawmaker did not respond to repeated requests for an interview.
One commercial appearing on cable television in his district attacks "obstructionists" blocking an immigration overhaul. Another accuses him of "talking about legalizing 11 million illegal aliens, making it easier for them to take jobs."
After a union-backed protest in Mr. McCarthy's district in August, demonstrators marched into his office with pictures of immigrants, along with farm tools and produce, in an attempt to illustrate their impact on the community here. In the arid Central Valley, where dairy farms and peach and almond orchards stretch for miles, immigrants have provided the steadiest source of agricultural and service employees.
Mr. McCarthy told a local radio station last week that most of the protesters had come from outside his district. Mr. McCarthy also faces pressure from those against illegal immigration. "He's shown that he is flexible on immigration and has said we need to be more open to foreign workers, but the great irony is that he's in a district with high unemployment," said Joe Guzzardi, the national media director for Californians for Population Stabilization, which opposes any kind of citizenship for those in the country illegally.
Advocates of a comprehensive immigration overhaul argue that California is a cautionary tale for Republicans in the rest of the country and that if the party does not help pass legislation this year, it will risk losing Latino votes for decades to come. Frank Sharry, the executive director of America's Voice, which is pushing for an immigration overhaul, points to 1994 as the start of problems for the state Republican Party. Pete Wilson, the governor at the time, led the campaign for a state ballot initiative severely limiting access to public services, including schools and emergency medical care, for illegal immigrants. Voters approved the measure, but it was ruled unconstitutional by federal courts.
"California became one of the bluest states in the country because the Republican Party followed Pete Wilson off the anti-immigration cliff," Mr. Sharry said. "McCarthy isn't going to want to lose more seats, and he has to see that members who are becoming champions of immigration reform aren't just living to tell about it, but they're getting love letters."
Across the state, other Republicans have softened their stance on immigration. Representative Ken Calvert, whose district covers Riverside County, has said he supports citizenship for those who were brought to the country as children and would consider some kind of legal status for others. Representative Gary G. Miller, whose district in San Bernardino, east of Los Angeles, is roughly 50 percent Latino and considered a prime target by Democrats, removed several strongly worded statements against immigration from his Web site this year.
Mr. Valadao's experience during an open house one recent evening illustrates the competing pressures. Minutes before a group of young students thanked him effusively for his immigration stance, two longtime residents denounced him, saying he was "rewarding lawbreakers" and "stealing American jobs."
He politely argued that illegal immigrants already made up about half of the agricultural employees in the area and that he had heard from dozens of farmers who said they could not fill jobs fast enough. But neither woman appeared swayed.
It is a point he has grown practiced at making. "It's complicated, but the more I looked at it here, the more convinced I became that we need to give some kind of hope to people who are working here, supporting their families and doing everything else right," Mr. Valadao said in an interview at his district office in Hanford, a small farming town in the middle of the state.
Angelica Salas, the executive director of the Coalition for Humane Immigrant Rights of Los Angeles, said Republicans were "sort of wedged between a rock and a hard place of their own doing." The coalition organized dozens of events singling out Republican congressmen last month.
She said Mr. McCarthy had met with her and other activists and signaled that he was open to supporting citizenship. "What I see him trying to deal with is the recognition that there's a real interdependence on immigrant labor in his district," Ms. Salas said, "but also some very shrill Republicans who either don't get it or don't care."
While Mr. Valadao said he did not have plans to increase pressure on his Republican colleagues, other local leaders have been more willing to openly voice criticism.
"We have people who graduated from our colleges who can't get jobs because they can't get citizenship," said Mayor Harvey L. Hall of Bakersfield, a Republican who spoke onstage at a protest directed at Mr. McCarthy. "All you have to do is go out on the weekend, and you can see that our growth as a city depends on the immigrant population."
For the most part, immigration campaigners are counting their successes. By one tally, about two dozen House Republicans have said they might support a path to citizenship. But Mr. Nunes, who is included in that number, said the attention focused on Mr. McCarthy could backfire, as Republicans in other parts of the country see unions and other Democratic allies focus on immigration as a partisan issue.
"Making a lot of noise and ruckus with someone open to change is just not credible -- it makes people harden their stance," Mr. Nunes said. "I want to come up with a way to get something done, but it's looking like people just want the issue as a piñata for political rhetoric."
This article originally appeared in The New York Times.