In California primary election, all hands on deck in Southern California to make it through A top two primary system and a flurry of candidates leave little room for error.

HUNTINGTON BEACH, California --

California's crowded primary shapes up to be crucial for Democratic hopes of retaking the House of Representatives in November.

The state has seven Republican-held districts that voted for Hillary Clinton in 2016 – and are now opportunities for Democrats. That's nearly one-third of all congressional seats Democrats need to flip to win the majority come Election Day.

The fight for the House centers here in the three battleground districts touching Orange County -- where vacant seats, a weakened incumbent and changing demographics have fueled both hopes of a blue wave and intense gamesmanship to make it happen. With 47 candidates running across the three districts, it's become even more of a challenge to make it through the state's so-called "jungle" primary, where the top two vote-getters, regardless of party, will go to the general election.

For many candidates, it's their first foray into national politics. For the parties, it's a test of having too much of a good thing – as a crowded primary field with these primary rules could splinter the vote and give the November election to the opposing party.

Federal Election Commission numbers show that in California's 39th, 48th and 49th Congressional Districts, the 14 Democratic candidates who are still actively running had raised nearly $25 million by primary day – more than two-thirds of which came from the candidates’ own wallets in races where self-funding millionaires have gotten a push from national groups.

It's an area where national Democrats have spent more than $8 million to ensure one of their own will make it through, rolling out ads against both Republicans and lesser-known Democrats threatening to splinter the party vote.

Orange County and parts of neighboring San Bernardino and San Diego counties have traditionally made up a Republican enclave in sapphire-blue California. It's the birthplace of Richard Nixon and Ronald Reagan, and many companies based in this home of so-called "country club" Republicans have claimed to benefit from President Donald Trump's tax policies.

California Republicans have even seized on Trump’s latest anti-immigration push and bet that anger at the state’s “sanctuary state” laws will mobilize the party’s anemic base in November.

But this is not Trump country. While Republicans here still tout the largest share of registered voters in Orange County, growing anti-Trump sentiment and opposition to some of the administration's policies have resulted in a surge of liberal activism aiming to convert the districts.

And the fight is on for every vote.

In the 39th Congressional District, where Rep. Ed Royce, R-Calif., is inching closer to retirement, 17 candidates are jockeying for the top spot, and money – both from personal fortunes and outside donations – in a race marked by intra-party warring.

It was nearly four months ago that the campaign for Mai Kahn Tran, a first-time Democratic candidate who quickly fundraised and gathered endorsements of groups such as Emily's List, told ABC News that the party and the Democratic National Committee (DCCC) preferred moneyed candidates.

“On one side they encourage all women to run and to speak up, and on the other side they prefer self-funded millionaires over any women [in the race],” the campaign told ABC News.

Now, Tran trails Democrats Gil Cisneros and Andy Thorburn, and Republican Young Kim in the vote.

"You cannot spend millions and show up just before the election cycle, right before, and think you’re going to win the election," Kim, the frontrunner, told ABC News.

The DCCC says it is "keeping all options on the table."

“Grassroots activists have been critical to holding House Republicans accountable, and the DCCC has recognized and appreciated their success and influence in making these races competitive," said DCCC spokesman Andrew Godinich in a statement to ABC News. "Working alongside grassroots activists and the California Democratic Party, the DCCC is keeping all options on the table to ensure that voters have a Democrat on the ballot this November.”

Until recently, Cisneros and Thorburn were locked in a months-long feud involving negative ads, threats of legal action, accusations of fraud and comparisons to Trump.

A truce had to be brokered, so the negative publicity didn't lock both candidates out of the running.

Farther west in Huntington Beach, it's a tale of two Californias as 14 candidates battle it out for the second spot in a primary against incumbent Dana Rohrabacher in the 48th Congressional District.

Five campaign signs Sunday dotted the corner of Adams and Newland in this coastal city – three of them in support of congressional candidates taking on Rohrabacher.

There's a big sign for Republican Scott Baugh – a former Rohrabacher protege – and another for Democrat Hans Keirstead, who was the party favorite until the DCCC endorsed fellow Democrat Harley Rouda.

A few blocks west, closer to the pier and in front of Rohrabacher's beachfront office, Rep. Pete Aguilar, D-Calif., came down from San Bernardino County to rally for Rouda. Several dozen people listened as he warned of the dangers of the "jungle" primary system.

He would know -- he's the only current congressman to have been shut out of a race since California adopted the system in 2010.

"Every vote counts. And people say it, but I live it," he told a crowd of about 50, who held "blue wave" signs for surfers making their way to the beach.

Rohrabacher, who has been in Congress for nearly three decades, has become a polarizing figure on his home turf. His connections to Russian President Vladimir Putin and the Kremlin are scrutinized, and critics point to the fact that in 30 years he's only passed three pieces of legislation.

Democrats are fighting for dear life to avoid getting shut out of the race. National Democrats and progressive groups have spent north of $100,000 propping up lesser-known Republican candidate John Gabbard in a ploy to splinter Republican votes for Baugh, who is closing in on that second spot in the primary.

That's on top of a multimillion-dollar effort by the group and other super PACs to knock Baugh down the ballot.

Down the Pacific Highway is the state's 49th Congressional District, where weekly protests lasting 67 weeks are credited with driving Rep. Darrell Issa into retirement, Democratic congressional candidate Mike Levin slouched in front of his laptop making calls to supporters and asking them if they had already mailed in their votes.

"Hi Dorothy, it's Mike Levin, Democrat for Congress – this is not a recording, it's really me," he said, as volunteers around him called John and Judy and Ellen and Laura asking them about their primary-day plans.

Some discussed the other candidates – there are four Democrats and eight Republicans running here, along with four independents. Doug Applegate, who almost beat Issa in 2016 – losing by less than a percentage point – is running again as a Democrat, with Sara Jacobs and Paul Kerr rounding up the group.

Elsewhere, volunteers for all campaigns walked and canvassed, as did candidates who -- door knocking until late in the afternoon -- looked to convert last-minute undecided voters.

With a nearly $15 million price tag, it's one of the most expensive races in the nation -- and while some Democrats here feel like they have a spot in the race, the fear of getting locked out of the November election is palpable.

Late polls have Levin facing off with Republican Diane Harkey, who Issa personally recruited to run.

Harkey, a member of the state's Board of Equalization and former mayor of Dana Point, is not a Republican apologist, and while she says the district is still Republican at heart, she recognizes her party's shrinking influence – and blames that on outreach.

"Sometimes it takes a fresh face – somebody new. ... It's very difficult to get in the press when you have Donald Trump occupying the press," she said. "I do think California would do a lot better if [Democrats] did a little bit less resisting. I think we paid a price for all the resistance."