Republicans badly need a few lucky breaks to hold their House majority in November. So far in 2018, it's been the opposite story — from an unfriendly new Pennsylvania map to Speaker Paul Ryan's retirement and bleak special election results. But with five weeks to go before California's June 5 primary, Democrats are at risk of squandering several seats that would otherwise appear to be golden pickup opportunities.

Democrats' path to a majority depends on California more than any other state: they have excellent chances in seven GOP seats that Hillary Clinton carried in 2016, and a few more could be long shots in a wave. But in at least four districts, Democratic over-enthusiasm has produced crowded fields that could lock Democrats out of the fall race altogether.

Under California's unorthodox "top two" primary system — first implemented in 2012 — all candidates appear on the same June primary ballot and the top two finishers, regardless of party, advance to a November runoff. In 2012, catastrophe struck Democrats when their top candidate in the new 31st CD, Pete Aguilar, took third place in the primary behind two Republicans, locking them out of a highly winnable race (Aguilar won the seat in 2014).

The same fate could befall other Democrats in 2018. In the 39th, 48th and 49th districts -- all Orange County GOP seats that voted for Clinton — the "blue wave" has generated throngs of viable Democratic candidates in districts where GOP voters traditionally make up a majority of the primary vote. And while Democrats have struggled to break out of their packs, there are at least two viable Republican candidates on the ballot in each of those races.

At the moment, Democrats face the greatest danger of a shutout in the 48th CD, where Rep. Dana Rohrabacher faces a credible challenge from former Orange County GOP chair Scott Baugh and three credible Democrats will be dividing their party's vote. But it's also possible Democrats could fail to make the fall ballot in the 39th and 49th CDs, where Reps. Ed Royce and Darrell Issa are retiring, as well as tarnished Rep. Duncan Hunter's 50th CD.

Democrats have had nightmares about "lockout" scenarios all cycle. And in some ways, the DCCC is in a paralyzing predicament. If top House Democrats don't insert themselves in races and a Democrat fails to advance to November, they would get blamed for whistling past a train wreck. But whenever they do, they risk looking like aloof meddlers and tarring their intended beneficiary as the candidate of "Beltway insiders."

The DCCC has been most assertive in the 39th CD, adding retired Navy officer Gil Cisneros to its Red to Blue list to try to help him break out of a six-Democrat pack. Democrats have also succeeded in pressuring several lower-tier candidates to drop out of races to improve their odds, including Phil Janowicz and Jay Chen in the 39th CD and Laura Oatman and Rachel Payne in the 48th CD (though it's too late to take their names off the ballot).

But over the next month, it may have no choice to take more aggressive action in the 48th and 49th CDs to avoid lockouts. That could involve engineering high-profile endorsements for one Democrat or strategically attacking certain GOP candidates with independent expenditures.

It's an unenviable task, because DCCC Chair Rep. Ben Ray Lujan and House Democrats are operating in a much different media environment than the one 2006 DCCC Chair Rep. Rahm Emanuel faced. In 2006, activist blogs were a relatively new political phenomenon and it was easier to maneuver behind the scenes. In 2018, jilted campaigns routinely leak damaging audio to The Intercept and social media, not DC, makes or breaks candidacies.

The GOP's lack of viable statewide contenders and Trump's unpopularity on the West Coast could be an existential threat to the 14 remaining Republicans in California's 53-member delegation. But the state's top-two system could throw some of them a life raft. Traditionally, the state's June electorate is much older and more Republican than its November electorate, and Democrats must increase their own voters' participation to avoid catastrophe.

Democrats' potential for Golden State gains hinges on high-stakes primaries in the seven districts below — especially those in the 39th, 48th, and 49th.

Updated Bottom Lines

CA-10: Jeff Denham (R) - Central Valley: Modesto, Tracy

Toss Up. Denham is a perennial target in a Central Valley district that is 42 percent Latino and voted for Hillary Clinton 48 percent to 45 percent. He's assured to advance to November, but the race for the second runoff slot is likely to come down to three Democrats: 2014/2016 nominee Michael Eggman, venture capitalist Josh Harder and former Riverbank Mayor Virginia Madueno. But with six Democrats and two Republicans on the ballot, a lockout scenario exists.

Harder grew up in Turlock and has raised the most money ($1.2 million), but his years working in San Francisco could make him easy to peg as an elitist in November. Eggman, a bee farmer who took 48 percent in 2016, got a late start but could be the frontrunner thanks to his name ID. Madueno is the only Latina and has EMILY's List's endorsement, but has only raised $226,000 and may split female votes with nurse/Modesto school board official Sue Zwahlen.

It's unlikely, but if Democrats split their votes evenly enough, it's theoretically possible GOP former Turlock Councilman Ted Howze could finish second and lock Democrats out entirely. After all, in 2016, Republicans took 58 percent of the primary vote here to just 42 percent for Democrats. Howze, a large animal veterinarian, has loaned his campaign $136,000 and claims he isn't running as a spoiler. As long as a Democrat advances, it's a Toss Up.

CA-25: Steve Knight (R) - Northern LA County: Santa Clarita, Palmdale

Toss Up. Democrats don't face any risk of a primary lockout here, but they do run the risk of nominating the "wrong" candidate. Knight faces four Democrats on the June ballot, but the race for the second runoff slot is between non-profit executive Katie Hill and 2016 nominee Bryan Caforio. The "Beverly Hills trial lawyer" label doomed Caforio in 2016, and a Caforio nomination could help Knight survive in a district Hillary Clinton carried by seven points.

Hill, 31, grew up in the district (unlike Caforio) and has run one of the largest anti-homelessness non-profits in the state. She owns guns and horses and culturally fits this parochial seat. Her first ad features her narrating her pitch while mountain climbing. She would offer a stark generational contrast to Knight, who has a tendency to shoot from the lip. And with the help of EMILY's List and LGBT groups, she's outraised Caforio $1 million to $883,000.

But despite her general election appeal, Hill isn't a sure bet to advance to November. Caforio is running as the "true progressive," retains plenty of name ID from his last race and is fond of replaying an old endorsement video President Obama cut for him in 2016. Meanwhile, Hill risks splitting women's votes with two minor Democrats on the ballot, volcano scientist Jess Phoenix and former Oak Park school board member Mary Pallant.

If Hill advances, Knight would probably become the underdog. If Caforio advances, Knight would still have a chance of keeping this seat in the GOP's column.

CA-39: OPEN (Royce) (R) - Northern Orange County: Fullerton, Yorba Linda

Lean Democratic. House Foreign Affairs Chair Rep. Ed Royce's retirement after 12 terms gives Democrats an excellent opportunity to pick up a melting pot Orange County seat (about a third each white, Latino and Asian) that voted for Hillary Clinton by eight points. But with seven Republicans and six Democrats on the June primary ballot, the race to advance to November is a free-for-all and Democrats are rightfully nervous.

Most Orange County politicos believe Korean-born GOP former Assemblywoman Young Kim will finish first in June. Kim, who once worked in Royce's district office and narrowly lost her Assembly seat in 2016, is running with Royce's endorsement. But the race for the second runoff slot could come down to a pair of Democratic self-funders, Gil Cisneros and Andy Thorburn, and GOP former state Sen. Bob Huff.

The DCCC has tried to clear a path for Cisneros by adding him to its Red to Blue list. Cisneros, a former Navy officer and Frito Lay manager, won a $266 million Mega Millions jackpot in 2010 and subsequently launched several philanthropic ventures, including a scholarship fund. But Thorburn, a retired insurance executive and New Jersey transplant, is still in the way. He's loaned his campaign $2 million to air ads pledging to impeach Trump.

In the last few days, the Cisneros-Thorburn duel has taken a bizarre, ugly turn. Thorburn leaked voicemail audio to The Intercept of someone purporting to be Cisneros warning him that he was about to "go negative." Cisneros insists the voice isn't his, citing the forensic analysis of the audio. Regardless, Cisneros has felt compelled to launch an offensive against Thorburn, accusing his insurance businesses of evading taxes.

There are also four other Democrats on the ballot, including pediatrician Mai Khanh Tran, who has EMILY's List's endorsement. Tran has $570,000 on hand, lagging Cisneros and Thorburn, and has yet to catch fire. But she's the only serious female Democrat and the only East Asian Democrat in a district that's 29 percent Asian, so she could still take a substantial share of the primary vote, increasing Democrats' shutout risk.

In addition to Kim, there are six other Republicans on the ballot, but the only serious contenders are Huff and Orange County Supervisor/former Fullerton Mayor Shawn Nelson. Nelson is running on ending sanctuary cities and has raised more money ($397,000 all cycle), but Huff ($281,000 all cycle) has a distinct geographic base in the Diamond Bar area and has plenty of name ID from serving in Sacramento for over a decade.

In 2016, even with the Clinton-Sanders race raging above on the ballot, Republicans took 60 percent of primary votes — scary math for Democrats. Democrats succeeded in convincing 2012 nominee Jay Chen and scientist Phil Janowicz to exit before the filing deadline, but an all-Republican November race is still possible. Even if a Democrat advances, Republicans believe Kim's profile as an Asian-American woman gives them a chance to keep the seat.

CA-45: Mimi Walters (R) - Inland Orange County: Irvine, Mission Viejo

Lean Republican. This is the only Orange County seat where Democrats are guaranteed to advance to the November election, because Walters is the sole Republican on the ballot. The question is which UC-Irvine law professor she'll face: Dave Min, a former adviser to Sen. Chuck Schumer and the Center for American Progress, or Katie Porter, a consumer protection lawyer and former student of Sen. Elizabeth Warren at Harvard Law.

Min is regarded as a moderate and won the California Democratic Party endorsement. But Porter is running as the progressive and has endorsements from Warren, Sen. Kamala Harris and EMILY's List. She's also the only Democratic woman running. Former White House technology adviser Brian Forde and former Sen. Sherrod Brown aide Kia Hamadanchy are running too, but trail Min and Porter for the second runoff slot.

Despite sitting in an upscale, white-collar district Hillary Clinton won 49 percent to 44 percent, Walters will be tough to beat. She's a fiscal conservative and a member of the moderate Republican Main Street Partnership and had $1.7 million on hand in March. But Min has received high marks for his playful ads and could develop into a strong opponent if he makes it past the primary. Porter's connections could make her a tougher sell.

CA-48: Dana Rohrabacher (R) - Coastal Orange County: Huntington Beach

Toss Up. Rorabacher's idiosyncrasies -- he's a surfing, pro-cannabis Republican — have worked for him here since 1988. In 2018, however, his bizarre association with Julian Assange and praise for Russian President Vladimir Putin have made him a lightning rod in a coastal seat Hillary Clinton carried 48 percent to 46 percent. But now there's a new plot twist: Democrats are in deep danger of failing to advance to the November election in the June primary.

Hours before the filing deadline, former Orange County GOP Chair Scott Baugh announced he would run against the incumbent. Baugh, a Rohrabacher protege and former assemblyman, had raised over $500,000 the last few years preparing for an open seat. But now he claims Rohrabacher broke his private promise to retire and is running ads accusing the incumbent of taking "172 taxpayer-funded trips to promote marijuana and Russia."

Baugh's candidacy severely complicates Democrats' path to November, because there are eight Democrats and only six Republicans on the June ballot in a district where Democrats combined for only 43 percent in the 2016 primary. Rohrabacher still appears likely to advance to November, but the only three candidates with a plausible path to oppose him are Baugh and two Democrats: stem cell researcher Hans Keirstead and real estate businessman Harley Rouda.

DC Democrats were ecstatic when Keirstead entered the race last June. A Canadian-born neuroscientist, Keirstead developed groundbreaking treatments for spinal cord injuries and late-stage cancers and sold a biotech company for $126 million in 2014. But he's also been accused of embellishing his resume (his PhD from the University of British Columbia is in zoology, not neuroscience) and there are rumors about why his association with UC-Irvine ended.

In February, Keirstead won the largely ceremonial state party endorsement at convention. But since then, Democrats have grown more worried about his opposition research file and more members of the House delegation have gotten behind Rouda. Rouda, an attorney and the son of a Columbus, Ohio, real estate titan, has campaigned on "Medicare for all" and ended March with $1.1 million on hand, including a $400,000 personal loan.

The danger for Democrats isn't just that Keirstead and Rouda could split votes fairly evenly; it's that there are six other Democrats on the ballot, including wealthy trial lawyer Omar Siddiqui ($861,000 on hand) and two women who withdrew under heavy pressure after it was too late to remove their names from the ballot: former Google executive Rachel Payne (who had EMILY's List's endorsement) and architect Laura Oatman.

Oatman and another withdrawn Democrat, Michael Kotick, endorsed Rouda. But Payne and Oatman could still attract female votes. Meanwhile, none of the other four Republicans are expected to spend much or encroach on Rohrabacher or Baugh's support. Of all the primaries in the state, this has turned into Democrats' biggest headache and Democrats may have no choice but to begin attacking Baugh to drive down his vote share.

CA-49: OPEN (Issa) (R) - Northern San Diego County: Oceanside

Lean Democratic. GOP Rep. Darrell Issa's retirement isn't turning out to be the gift some Democrats thought it might be. Issa eked out his reelection by just 1,621 votes in 2016 against retired Marine colonel Doug Applegate while Hillary Clinton carried this coastal San Diego district by seven points. But now, crowded fields on both sides and California's top-two primary increase the odds Republicans could hold on in an awful political climate.

Four Democrats and eight Republicans filed for the June primary, but there are four credible contenders on each side. An April SurveyUSA poll taken for the San Diego Union Tribune found GOP state Assemblyman Rocky Chavez leading with 16 percent to 12 percent for Applegate, a Democrat. The two former Marines would probably advance to November if the primary were held today. But they both had less than $250,000 on hand and will be badly outspent.

On the Democratic side, Applegate begins with the most support by virtue of his insurgency against Issa in 2016. Environmental lawyer Mike Levin has raised the most money -- $1.5 million — and has the support of seven members of the state's House delegation (he took third with nine percent in the SurveyUSA poll). But both Applegate and Levin could be overtaken by a pair of self-funders: policy analyst Sara Jacobs and Navy veteran Paul Kerr.

Jacobs, 29, is the granddaughter of Qualcomm co-founder Irwin Jacobs, who has donated to an EMILY's List-connected Super PAC advertising on her behalf. She's also given her campaign $1 million. Jacobs grew up in Del Mar, graduated from Columbia and served as a policy adviser for the Clinton campaign in 2016. But she's also come under fire for saying she served as a policy adviser at the Obama State Department when, in fact, she was a junior contractor.

As the only female Democrat and by far the youngest candidate, Jacobs could be a serious contender despite the resume inflation allegations. Jacobs's ads intersperse images of the Women's March with appeals for a new generation of leadership. But incredibly, she is likely to be outspent by Kerr, a real estate investor, who is rumored to personally spend over $4 million highlighting his military background and opposition to President Trump.

On the GOP side, San Diego County Supervisor Kristin Gaspar and former Dana Point Mayor Diane Harkey are in closest contention to Chavez, with wealthy financial adviser Brian Maryott a potential factor as well. Gaspar has the backing of San Diego Mayor Kevin Faulconer and is a natural in ads but splits a geographic base with Chavez, while Harkey has Issa's support and a base in the Orange County end of the district.

Most insiders agree that Chavez starts as a favorite for one of the two November slots, but the battle for the other is a free-for-all. In 2016, Republicans accounted for 51 percent of primary votes to 45 percent for Democrats, so any fall combination is possible. If self-funders Jacobs and Kerr catch up to Applegate and Levin, the Democratic vote could be split evenly enough to allow a second Republican, most likely Gaspar or Harkey, to sneak through.

CA-50: Duncan D. Hunter (R) - Inland San Diego County: Escondido, Santee

Likely Republican. For eons, this San Diego seat has been one of the safest GOP seats in the state (President Trump won it by 15 points). But Hunter, who succeeded his dad in office in 2012, is under FBI investigation for misusing campaign funds, including flying his pet rabbit on a plane. His campaign has paid over $600,000 in legal fees, and it's tough to gauge whether his bigger threat is an indictment or an election loss.

Hunter faces two other Republicans and three Democrats on the June primary ballot. In 2016, Republicans accounted for 63 percent of primary votes to 33 percent for Democrats, so it's quite possible Democrats could divvy up their votes enough ways that Hunter could face a fellow Republican in November. GOP El Cajon Mayor Bill Wells had just $5,000 on hand at the end of March. GOP translation businessman Shamus Sayed had $157,000.

Meanwhile, Democrats have a credible candidate in retired Navy SEAL Josh Butner ($308,000 on hand), who served in the Gulf War, Afghanistan and Iraq. His profile could resonate in this military-heavy seat. But Butner will be splitting Democrats' votes with former Obama Labor Department official Ammar Campa-Najjar ($333,000 on hand) and 2016 nominee Patrick Malloy, who hasn't raised money but whose name has appeared on the ballot before.

It's likely the only scenario in which Democrats could win this seat is if both Hunter and Butner advance to November. The DCCC may have nothing to lose by going all-in for Butner, and nearby Rep. Scott Peters just endorsed him. But between a severely damaged incumbent (Hunter had just $309,000 remaining in his war chest in March) and a very crowded field, anything could happen.