BREA, Calif. — Confused and frustrated, a growing number of Democrats are blaming their own party as they seek to avert a drubbing in Tuesday’s congressional primaries here that would leave their candidates shut out of the November ballot in some races — and with a narrower path to win control of the House of Representatives.

In three Orange County districts, a surfeit of enthusiastic candidates and conflicting messages from Democratic organizations and allies have converged to complicate the party’s road to victory. All three districts are held by Republicans, and all three are widely seen as crucial to Democratic efforts to pick up the 23 seats they need nationwide to win the House majority.

Democrats have had internal conflicts in other states, but the circumstances in California are far more convoluted because of the state’s “top two” nominating system, in which the two highest vote-getters are elevated to the November ballot, irrespective of party affiliation. Two Democrats could make the general election ballot — or two Republicans, as happened in a 2012 House race.

With Democrats eyeing the 2018 elections as a chance for a blue wave, here's how they're fighting to win the 24 seats they need to take control of the House. (Jenny Starrs/The Washington Post)

The result, say activists, party officials and some candidates, has been anger among voters who fear destructive splits in the Democratic vote — and a level of chaos not seen in congressional primaries here in years, if ever.

Candidates are scrambling to set themselves apart, Democratic groups are urging unity to gain control of the House — and many voters are wondering how to contend with the despair they would feel if Democrats were locked out in this liberal state.

“I would do a Thelma and Louise — just drive over the cliff,” said Danna Lewis, 66, a doctor who lives in the 48th Congressional District and went door to door over the weekend for her candidate, Harley Rouda.

Across California, seven Republicans represent districts where Hillary Clinton carried the popular vote in 2016. That fact, coupled with an explosion of liberal enthusiasm since President Trump took office, led dozens of Californians to launch congressional campaigns.

But, separately, national and state Democrats spent much of 2017 recruiting wealthy challengers and encouraging others to switch districts, adding to the candidate mix. More problematic, two incumbent Republicans — Darrell Issa (whose district includes parts of San Diego County) and Edward R. Royce — announced that they will retire this year. What Democrats expected to be races between struggling incumbents and primary-tested Democrats became candidate dogpiles with unpredictable outcomes.

A third race that has typified the electoral confusion: Republican Dana Rohrabacher attracted a party challenger, former Orange County GOP chairman Scott Baugh. Democrats, rather than coalescing, took months to officially back one candidate, businessman Rouda — and did so only after initially encouraging stem-cell entrepreneur Hans Keirstead to enter the race.

Laura Oatman, a candidate in Rohrabacher’s 48th District, said the Democratic Congressional Campaign Committee created problems by recruiting Keirstead. According to Oatman, the committee then pressured her to drop out and endorse him — despite what she described as grass-roots enthusiasm at debates and other events for her and Rouda. (The committee denied Oatman’s claim.)

A disillusioned Oatman did drop out, but after the deadline for remaining on the ballot, and endorsed Rouda. And the DCCC eventually did, too, after allegations of misconduct surfaced against Keirstead. Keirstead denied the allegations, made in connection with his tenure at the University of California at Irvine, and remains in the race.

“They realized, ‘Oops! Boy, did we make a mistake,’ ” Oatman said.

The state Democratic Party, however, had followed the national committee’s lead and endorsed Keirstead. Democrats in the district are receiving sample ballots from the state party urging them to vote for Keirstead — and ads for Rouda touting the DCCC endorsement.

“There’s a lot of frustration,” said Fran Sdao, chair of the Orange County Democratic Party, who described an inbox flooded with emails from voters who don’t know who they’re supposed to support in Tuesday’s primaries.

At a canvass launch last weekend in Laguna Niguel, Rouda told volunteers that Keirstead had no chance at victory and was closing with negative attacks. Before heading out, the volunteers posed for a picture with their candidate and broke into a chant: “Knock doors, not Dems!”

In an interview at his home nearby, Keirstead said the DCCC had bought into “smears” about him despite a university probe that cleared him, and said the committee walked away when he refused to ask former students to go on camera to rebut charges that he had sexually harassed them.

“Harley was $450,000 above me. The DCCC invested $200,000. That equals $650,000,” Keirstead said. “So I wrote my campaign a check for $650,000. If they put in another million, I’ll do the same damn thing.”

A spokesman for the DCCC said that Oatman was not pressured to leave by the committee, as she left before the risk of a lockout grew, and denied that Keirstead was told to get accusers on video defending him.

Democrats’ ability to avoid a ballot lockout rests in some part on how the vote divides among Republicans in the races, said Paul Mitchell, a number-cruncher and vice president at Political Data who has been tracking absentee balloting in California’s primaries. In the 48th, that has led Democrats to take pre-primary aim at Baugh, hoping to depress his vote, even as Republicans portray Rouda as one of their own who, in Baugh’s words, became a “born-again socialist.”

“It’s kind of out of Democratic voters’ control whether they’re going to get somebody into that second spot,” Mitchell said.

Democrats have grown more cautiously optimistic in Orange County’s open seats, in part because Republicans have their own multicandidate races to contend with that could split the vote. But both races have been reshaped by candidate wealth.

In Issa’s district, the Democratic contest began as a battle between unsuccessful 2016 candidate Doug Applegate, a retired colonel, and Mike Levin, a lawyer. But both have been heavily outspent by real estate investor Paul Kerr and Obama administration veteran Sara Jacobs, whose grandfather Irwin co-founded mobile giant Qualcomm.

On the trail, neither Applegate nor Levin disguised their contempt for their challengers’ wealth. In an interview after a Memorial Day ceremony, Applegate warned that Jacobs “wouldn’t get a single vote” from veterans, “the largest demographic in this district.” At a house party this weekend, Levin fielded question after question about Kerr’s negative mailers. To calm supporters, he ticked off his endorsements from labor unions and said their members added up to enough votes to make the runoff.

“I don’t have a billionaire for a grandfather. I’m not worth $300 million from my real estate empire,” said Levin, referring to Jacobs and Kerr. “I’m a regular person.”

Jacobs has earned support from Emily’s List, the Democratic fundraising powerhouse that promotes female candidates who support abortion rights — and that received an infusion of $1.25 million from Irwin Jacobs. Its ads, like Jacobs’s own spots, say that she could “change the face of Congress” in a way her male opponents could not. In an interview, Jacobs said that her wealth had simply leveled the playing field.

“We know it takes resources to run,” Jacobs said. “There was a calculation that if we wanted a woman in the race, it had to be someone who had resources to bring to the campaign, and I am fortunate that I am able to do that.”

The wealth issue has loomed even larger in the contest for Royce’s 39th District seat. Early on, the DCCC recruited and endorsed Gil Cisneros, a veteran and former Republican who won a $266 million lottery jackpot in 2010 and began pouring money into philanthropy — and donations to Democrats. Some challengers simply quit.

Most did not. Cisneros’s endorsements rankled Mai Khanh Tran, a doctor who raised more than $900,000, invested $500,000 of her own money and entered the race after Democrats said they would back someone else in the 48th District, where she lived. Also in the race is Andy Thorburn, a wealthy insurance executive running as a Bernie Sanders-style populist and who, until a truce was declared last week, was trading attacks with Cisneros.

None of the candidates won the state party’s endorsement.

“It’s complicated; it’s convoluted,” said Thorburn as he campaigned recently. “What role should the party play in the process? I don’t think anybody has a good answer for that.”

The party’s lack of control was highlighted again last week, after Herbert Lee, a doctor who had skipped most of the district’s candidate forums, put $750,000 of his own money into advertising.

“In some of these races, it’s very difficult because you don’t have any leverage,” said Steve Smith, communications director for the California Labor Federation, which is backing the same candidates as the DCCC. “These are self-funded candidates. If they want to run, they’re going to run whether the DCCC says otherwise or not.”

Still, some voters are seeing through the conflict. Carson Newton had seen the ads, the lawn signs and the piles of glossy campaign mail. He decided to help Cisneros after he learned of the DCCC’s endorsement.

“I’m here because the DCCC chose him as the candidate most likely to win,” said Newton, a 40-year-old lawyer, as he scooped up precinct walk sheets at Cisneros’s campaign office. “I read one of those Democrats saying, ‘Now’s not the time for small ‘D’ democracy,’ and I thought, ‘That makes sense to me.’ ”

Gardner reported from Washington.