LAGUNA BEACH, Calif.—Harley Rouda knows he is a statistical anomaly. All the research says people don’t switch political affiliations, even when they disagree with their party on key issues. It’s one of the inexorable truths of American partisanship.

“Your religious and political identity is given to you at birth, right?” Rouda, 57, told me recently, recounting his upbringing in a conservative, Christian household. “I don’t think anybody holds their hand up and says at 6, 7 or 8 years old, ‘Hey, Mom and Dad, I’m not feeling Christian or Republican. I’m thinking about making a switch.’ And that was true for me as well.”

Until one day it wasn’t true any longer.

In 2017, Rouda, a one-time Reagan and Bush voter who had quietly severed his Republican ties to identify as an independent, made the rarest of transformations. He registered as a Democrat with the express purpose of running against a 15-term Republican congressman in Orange County, a place famous as a redoubt of the California GOP. He won by 7 points.

Rouda won because Orange County has changed dramatically, too. What was once an 18-point Republican advantage in voter registration just a decade ago evaporated, permitting the unthinkable to happen in 2016 when Hillary Clinton won the county by nearly 5 points, becoming the first Democratic presidential nominee to win here since 1936.

And then last year, Rouda and three other Democrats swept the congressional races, eradicating the GOP from the electoral map in a place that Ronald Reagan once described as the place “where good Republicans go to die.” Democrats’ blue wave in 2018 was more like a blue tsunami in this affluent and scenic sanctuary nestled between the urban sprawls of Los Angeles and San Diego.

The mortification of the GOP on its home turf came due to two primary factors: an influx of young and Latino voters who have diluted the power of the white conservatives who long defined the county, and a split inside the Republican party itself, driven by its nominal leader, President Donald Trump. Rouda defeated longtime Rep. Dana Rohrabacher (R-Calif.) in no small part because of the incumbent’s close ties to Trump and his longtime support of the Vladimir Putin regime in Russia.

“It’s not that Orange County’s values have changed; it’s that the Republican party’s values have changed. And they’ve completely lost touch with reality and the vast majority of voters,” Rouda told me as he sipped a Starbucks iced latte with soy milk just 15 miles from Richard Nixon’s “Western White House.”

While the demographic trends show no hint of weakening, it’s an open question whether those disaffected Republicans are, like Rouda, permanently done with the GOP—or whether they can be coaxed back in a post-Trump world. There is a fierce battle already underway, from the marble halls of the Capitol to the beaches of southern California, to decide Orange County’s fate—and, in turn, that of the House majority post-2020.

Recently, I spent time in Rouda’s district—which he gleefully touts as the “most beautiful congressional district in the country”—and Orange County’s three other congressional districts. On the day I shadowed Rouda, he was dressed almost as if we were walking in a hallway inside the Capitol—navy blue suit and leather shoes, the lack of necktie the only concession to the balmy weather. More than once during the day, the kind of Orange County voter that Reagan would have recognized—white retirees walking their dogs on the beach—approached Rouda. Some just wanted to shake his hand. Others simply shouted, “I voted for you!”

Politicians in Orange County, like in many American suburbs, are becoming less dependent on these older white voters for their coalition. Orange County, in a very short time, has become younger and less white—and when paired with Trump’s election in 2016, that shift cemented Orange County’s status as ground zero for Republicans’ struggle to attract young voters, moderates and minorities, especially in suburban America.

“Since Donald Trump came into the picture, we have seen this huge uprising,” Ada Briceño, who chairs the Orange County Democratic Party, told me.

But there is another salient truth about that might prove just as consequential in 2020: Voters who left the Republican party in the last cycle didn’t register as Democrats; they overwhelmingly became independents. In short, they were up for grabs in 2018 and they’re still up for grabs a year later.

That’s one of the reasons that despite positioning himself as a fiscally conservative moderate in an increasingly progressive Democratic party, Rouda will face a difficult race in 2020 to keep his job. A recent poll commissioned by a Republican super PAC, for example, shows a neck-and-neck race between Rouda and his presumed GOP opponent. He’s not alone; all four lawmakers who represent parts of Orange County—Rouda, Gil Cisneros, Katie Porter and Mike Levin—are at the top of Republicans’ list of lawmakers they consider most vulnerable as the GOP tries to wrest back control of the House.

As unpopular as Trump is here, Democrats worry they could blow it. As the party’s loudest voices embrace progressive agenda items like Medicare for All and tuition-free college, the four freshman lawmakers who edged out Republican opponents, in part by portraying themselves as moderates who would stand up to their own party when necessary, will have to convince crossover voters that they’ve been true to their word. That tightrope will become even more difficult to walk as the House Democrats, emboldened by the latest allegations involving Ukraine, march toward impeaching the president.

“It wasn’t easy to win this seat,” Levin warned sternly at a recent town hall in the beachside city of Del Mar. “And it won’t be easy to hold this seat.”

***

Rouda’s break-up with the party he had grown up in didn’t happen overnight.

The first breach came in the late 1990s. He blamed then-Speaker Newt Gingrich (R-Georgia) for ushering in a new era of conservatism that Rouda felt was “not recognizable” to Reagan’s GOP—in particular, its drift away from fiscal responsibility and compassionate immigration policies, and the party’s preoccupation with social issues like same-sex marriage. (Gingrich, no fan of Rouda’s either, has already endorsed Rouda’s opponent, Michelle Steel. Steel was not available for an interview.) At first, he simply described himself as an independent.

“Up until 1997, you had a Republican party that believed in environmental stewardship, believed in the right of everyone to vote, believed in reducing deficits,” Rouda said. “And that’s certainly not the case now. At best, all of those issues are on the backburner if not off the stovetop altogether.”

A frustrated Rouda then threw his hands up.

“I mean, does anybody really think Ronald Reagan could get elected [today]?” he said. “I liked the way he saw the city on the hill and how he talked about everyone in our country having a fair economic opportunity, that immigration is a positive thing.”

Around the same time that he contemplated leaving the GOP altogether, he married Kaira Sturdivant, a liberal Democrat who supported Jimmy Carter. They sparred occasionally over politics, but in the end, Rouda joked: “Apparently she had more influence on me than I had on her.”

He voted for George W. Bush in 2000—but that was the last time he voted for a Republican at the top of the ticket. Bush’s invasion of Iraq in 2003 angered Rouda. “[That] kind of sealed the deal. Like, I’m done with this party,” he said.

Rouda moved to Orange County from Ohio in 2007, managing his real estate law practice from one of the priciest zip codes in all of California. Still, he continued donating to Republican candidates even after leaving the GOP. In 2016, he contributed $1,000 to then-Ohio Governor John Kasich’s presidential campaign, citing his friendship with Kasich and his desire to see Trump defeated in the GOP primary. When Kasich inevitably dropped out, Rouda was faced with a choice between Trump and Clinton. He lamented that the 2016 election “almost came down to who you disliked more.” He chose Clinton and, in 2017, registered as a Democrat for the first time in his life. Shortly thereafter, he announced his candidacy to take on Rohrabacher.

Some progressives took issue with Rouda’s past as a Republican. But they also saw it as a boon—an opportunity to appeal to conservatives disaffected with Trump in a district that Clinton won by nearly 5 points (39,000 votes) in 2016. Rouda’s seven-point victory over Rohrabacher validated their instincts.

Both political parties are trying to figure out whether political shapeshifters like Rouda are outliers—or, if they’re bellwethers for a more dramatic shift to come.

***

The last time Orange County recorded a Democratic voter registration advantage was Oct. 13, 1978—a brief response to the Watergate scandal, as Republicans dominated for decades before. Mike Levin was born seven days later. It took 41 years for Democrats to re-gain that advantage.

Even before Rouda arrived here, Levin — who represents southern Orange County and parts of San Diego County — could see the trend from his perch atop the Orange County Democratic party, which he ran in 2006 and 2007. At the time, Republicans had an 18-point advantage over Democrats in voter registration.

In the 12 years since he ran the local Democratic party, the demographics in Orange County have undergone sweeping changes. Latino voters make up 21 percent of Orange County’s electorate, up more than a third since 2016 as more have gained American citizenship. Hispanic voter turnout sharply increased, in what was likely a response to Trump’s hardline immigration rhetoric. Clinton’s 2016 victory here shocked Republicans—and just two years later, the county’s GOP lawmakers were wiped out completely.

“The Asian population is growing. The Latino population is growing. And with that demographic change, you also see a change in the way people vote,” said Gil Cisneros, 48, a lifelong resident of Orange County who, like Rouda is also a former Republican.

Cisneros, whose district also includes parts of Los Angeles County and San Bernardino County, voted for Ross Perot in the 1990s and John McCain in 2008 but turned away from the Republican party shortly after that election, when he watched fringe voices push racist conspiracy theories about whether Barack Obama was a Muslim who was born in Kenya.

“A lot of racist tendencies were coming out. And it just wasn’t something that I wanted to be associated with,” Cisneros told me defiantly over coffee in Buena Park. “By 2008, you could really see the tides moving. The direction the Republican party was moving in was not the Republican Party that it was 20 years ago.”

Democrats have also seen gains here among voters ages 18 to 34. In 2002, 42 percent of them were registered Republicans, compared to 29 percent for Democrats. This year, 38 percent of those voters are registered as Democrats, and just 20 percent as Republicans. The share of independent voters also sharply increased during that same time period, from 22 percent to 42 percent.

While the Latino boom in Orange County has helped Democrats, the surge of Asian-Americans has been less conclusive. While Asian-American share of the electorate has ballooned to 16 percent, registration numbers show that 29 percent are Republicans and 30 percent are Democrats. Forty-one percent are registered with neither party.

Today, Orange County has the third-largest Asian-American population in the country, and it’s particularly visible in Irvine, where Katie Porter’s district falls. Asian-American voters tend to be more conservative, but some analysts have pointed to Trump’s immigration rhetoric as the key reason why turnout in favor of Democrats has increased for this key group.

Two of the likely GOP nominees in Orange County’s four congressional districts are Asian-American women. Cisneros will have a rematch in 2020 against his 2018 GOP opponent, Young Kim, a Korean-born businesswoman and former state legislator; Rouda will likely face off against Steel, a county supervisor who was also born in South Korea.

Steel, Rouda’s opponent, is largely aligned with Trump, which the Rouda campaign plans to drill into voters’ minds here. She co-chairs his presidential advisory commission on Asian-Americans and Pacific Islanders. Steel was also the only elected official to greet the president when Air Force One landed at Los Angeles International Airport last March, his first official visit to California.

Kim, too, supports the president’s policies, telling me that Trump deserves credit for the strength of the U.S. economy. She has praised him for slashing federal regulations and signing a sweeping tax-overhaul bill into law—one that many California Republicans actually opposed in part because it capped the state and local tax deduction at $10,000.

“The bottom line is that these economic policies are woefully unpopular, these environmental policies are woefully unpopular, the immigration policies are woefully unpopular,” Levin added. “Hence the president’s approval here is in the 30s.”

“California Republicans are not like Alabama and Mississippi Republicans. They tend to be a little bit more liberal when it comes to social issues,” Cisneros said.

Rouda cited one of the key local Orange County issues — the threat of climate change — as one of the reasons he left the GOP. The Trump administration has rolled back several Obama-era emissions and air-quality standards—part of what Levin said is the president waging a “policy war on the state of California” with its efforts to restrict the state’s more progressive environmental and immigration standards. He believes it’s helping to drive voters here away from the GOP.

“We care about clean air, clean water, clean beaches. Because we live here. Because we see the impact of climate change,” Levin said, pointing to the beach 50 feet behind him as we sat on a picnic table. “Because we understand what it’s like when you don’t have those strict air quality requirements because we grew up here at a time when we had far worse emission standards.”

Randall Avila, the Orange County Republican party’s executive director, agrees with Democrats on one thing: Trump has driven suburban Republicans away. “He’s definitely a two-sided coin,” Avila said. “But his presidency and the passion on one side or another has accelerated that process.”

To reclaim its voter registration advantage, Avila said his organization will focus on Republicans who left the party to become independents. Some Orange County residents who left the GOP actually support the president, Avila said, and only did so in protest of the establishment wing of the party.

But Republicans who jumped ship over their dissatisfaction with Trump pose the biggest challenge for Avila, who said he plans to focus on local economic issues—rather than the beltway-driven Trump controversies that might push Republicans away from the president—in order to win them back.

***

Rouda’s own party has dubbed him a so-called “frontliner,” a list of several lawmakers whom the national party says are the most vulnerable in 2020. The National Republican Congressional Committee (NRCC), too, has Rouda near the top of its list, and the GOP still has a seven-point voter registration advantage in Rouda’s district, which includes more conservative pockets like Newport Beach.

The GOP’s argument to Rouda’s constituents is simple: You were swindled. The NRCC has already dinged him for supporting an impeachment inquiry into the president, and they’ve referred to Rouda as a “Socialist Democrat.” Moreover, Republicans say Rouda’s victory in 2018 was a fluke because Rohrabacher, notoriously apologetic for the Putin regime, was an unpopular and flawed incumbent. Translation: A level-headed Republican would fare better.

The “socialist” moniker won’t go away any time soon. Republicans are seeking to tie Democratic lawmakers to members of the so-called progressive “squad” like Reps. Alexandria Ocasio-Cortez (D-N.Y.) and Ilhan Omar (D-Minn.). In particular, they’ve seized on Omar’s recent anti-Semitic comments that have sparked intense backlash among members of her own party, including Democratic leaders and frontliners.

“Most voters also know that the ‘squad’ is not the leadership of the Democratic party. That may play well with the Republican base, but they’re not voting for us anyway,” Rouda said. “We got the majority back not by keeping blue seats blue; we got the majority by flipping red seats blue. And the people who did that are moderates—left-leaning moderates.”

But if one of the more progressive presidential candidates like Sen. Bernie Sanders or Sen. Elizabeth Warren emerges as the party’s 2020 nominee, it could be more difficult for vulnerable lawmakers like Rouda to distinguish themselves from the party’s left flank. Perhaps even more problematic, Democrats like Rouda will have a tougher time arguing for fiscal responsibility when the top of the Democratic ticket is calling for Medicare for All and tuition-free public colleges.

Both Rouda and Levin made impassioned pleas for fiscal responsibility. Rouda told me that Californians are over-taxed at the local, state and federal level; Levin brought up the national debt unprompted. Indeed, they believe that fiscal conservatism can help them continue to peel away Republicans who are disenchanted with the way Trump has presided over a runaway deficit.

“We’re ballooning our deficit and our debt, which I care very deeply about—not all Democrats do. I do,” he said. “I’m not a proponent of modern monetary theory. I am a proponent of fiscal responsibility and investment, and understanding the difference between an investment and a cost.”

Republicans are particularly keen on portraying Porter—who represents Irvine, Calif., and defeated incumbent GOP Rep. Mimi Walters last year—as a liberal Democrat who ran as a centrist. Porter has become somewhat of a progressive hero for her relentless questioning of witnesses at House Financial Services Committee hearings, including a viral grilling of JPMorgan Chase CEO Jamie Dimon over employee compensation. She has leaned heavily into that persona, joking at a recent town hall that Dimon has become her “pen pal.”

Avila, who runs the Orange County GOP, said both his organization as well as the national party apparatus plan to highlight that apparent dissonance, calling Porter a “national sensation” among progressives and citing her appearances on television shows like Bill Maher’s HBO program.

“While she’s attracted a lot of attention through online small donations from Democrats across the country, it’s putting her in a very awkward position here in Orange County with her constituents. She campaigned as a moderate,” Avila said. “And she said she was going to be a moderate voice in Congress, but she’s outing herself and giving us a lot of material to work with to show that she is very much far-left.”

Republicans also see a prime pickup opportunity in Cisneros’ district, which will feature a rematch of his 2018 contest against Kim. She is already seeking to tie Cisneros to Ocasio-Cortez, noting that he is a member of the Congressional Progressive Caucus.

“He said he would try to be a moderate person, yet he goes on to join the Progressive Caucus, whose agenda and policies are leaning further and further to the left,” Kim said in an interview. “And he votes with the likes of Progressive Caucus members like AOC over 90 percent of the time. So I don’t know what he has accomplished so far. I would like to see it.”

Still, Cisneros plans to highlight the national debt in order to woo Republicans disaffected with Trump.

“This is something that we Democrats need to communicate and that we need to do a better job and let people know that we are the party of fiscal responsibility, we are the party where the economy has thrived under us, and this is the party where workers have also had success and where they thrive,” he said. “We’re the party of the American worker.”

Kim described herself as an “independent voice” and noted that while Republican registration has declined in Orange County, the number of self-described independents has grown. That pool of voters will be critical for all candidates in the county’s four congressional districts in 2020.

While she supports the president, she tipped her hat to the steep decline in GOP registration by acknowledging that Trump’s personal behavior often turns voters off.

“People can say whatever they want to say about our president. I think they are talking about his style of speaking, his rhetoric, his attitude or whatever,” Kim said. “They may not like him as a person, but I hear that they do appreciate the policies that have made our economy really stronger.”

But for the Democrats now commanding the electoral high ground in Orange County, there is a belief that the disintegrating Republican party cannot reform around a single issue like the economy; there are too many other factors working against it, and most of them are exacerbated by the presence of Trump at the top of the ticket.

“I didn’t think Trump would get elected, and I thought he would potentially cause the demise of the Republican Party as we know it,” Rouda added. “I was wrong in one sense—he got elected. But I may still be right in the other sense, that the Republican Party as we know it may not exist after the Trump era.”

Cisneros concurs with his fellow ex-Republican, both of whom will be the Democrats’ anchors here in 2020 as the party defends its majority.

“If the [Republican] party continues to go down that route, I don’t see how it could survive,” Cisneros said of his former political affiliation. “I certainly don’t see how it could survive here in California. It’s going to continue to get smaller and smaller.”

He added, somewhat optimistically: “I always like to think that what happens in California eventually happens throughout the rest of the country.”