LOS ANGELES — As California goes, so goes the U.S. House?

A string of contested districts across the nation’s most populous state could provide a pathway for Democrats to take control of the chamber or help Republicans hold their ground in a year defined by divisions over President Donald Trump and the #MeToo movement against sexual harassment.

Ohio Rep. Steve Stivers, the Republican Party’s campaign chief in the House, summed it up plainly: the party’s majority runs through Orange County, California, where Republicans are defending four suburban seats long counted as GOP turf.

The California battlegrounds range from Central Valley farmland to legendary surfing spots to horse country north of Los Angeles. A torrent of money has flooded districts, with outside groups dumping over $10 million into several contests.

A president’s party traditionally loses ground in Congress in midyear elections, and Democrats Tuesday are hoping to claim 23 House seats nationally to put them in charge.

In California, Democrats have targeted seven GOP districts that were carried by Hillary Clinton in the 2016 presidential election. In play are long-term political trends that have seen the state grow more diverse in population and Democratic in its politics. The party controls every statewide office, both chambers of the Legislature and counts a 3.7 million edge in voter registrations.

In the House, Democrats in California hold a 39-14 advantage in seats.

Fight in the Farmland

Republican Reps. Jeff Denham and David Valadao represent farm-belt districts where Democrats have more registered voters but are moderate than in urban areas.

They are facing stiff challenges from Democrats, emboldened after Hillary Clinton carried the districts in 2016. In each case, their opponents will need a big showing from Hispanics, a group that historically has been unreliable voters.

In Denham’s 10th District, anchored in Modesto, Democrat Josh Harder has argued that Republican policies in Washington have hurt many residents. He’s emphasized that Denham voted to repeal the Affordable Care Act, which Harder supports.

But the congressman, known for his involvement in water issues vital to agriculture, has proven tough to beat, despite the Democratic registration edge. He won by 3 percentage points in 2016. Representing a district with a large Hispanic population, Denham has pushed for Congress to consider a pathway for citizenship for hundreds of thousands of immigrants who came to the U.S. as children and stayed here illegally.

Valadao is something of a political anomaly. His 21st District, which includes parts of Fresno, Kern, Kings and Tulare counties, is heavily Democratic. Yet he won by a wide margin in 2016.

He’s being challenged by Democrat T.J. Cox, who has tried to make the contest a referendum on Trump.

The Battle for Orange County

There was a time when talk of Democratic candidates seriously competing for House seats in the heart of Orange County would have been taken as a joke. After all, the county was once home to Richard Nixon and considered conservative holy ground. But demographics have shifted along with the county’s politics, and two seats being vacated by retiring Republican Reps. Darrell Issa and Ed Royce have given Democrats an opening.

In Royce’s 39th District, Republican Young Kim is hoping to become the first Korean-American immigrant woman elected to the House. The former state legislator worked for Royce for years and has positioned herself as a Trump supporter with an independent streak.

Democrat Gil Cisneros, a first-time candidate, says voters are eager for change in a district about equally divided between Democrats, Republicans and independents. The $266 million lottery winner and Navy veteran is looking for a big turnout from Hispanics who make up about a third of the population.

In Issa’s closely divided 49th District, Diane Harkey, who sits on a state tax board, is looking to replace her fellow Republican and has been endorsed by the president. But environmental attorney Mike Levin has been attempting to turn that endorsement against her in a state where Trump is unpopular.

Hanging On

Republicans are fighting to defend two vulnerable incumbents in Orange County, Reps. Mimi Walters and Dana Rohrabacher.

Both were easily re-elected just two years ago. But they are closely tied with Trump, who is unpopular in California, and represent politically moderate districts that have been growing more Democratic.

In the 45th District, which has a 7-point GOP registration edge, Walters is facing law professor Katie Porter, a protégé of Massachusetts Democratic Sen. Elizabeth Warren. She has campaigned on overturning Trump’s tax reform package and her support for universal health care.

Rohrabacher, known as Russia’s leading defender on Capitol Hill, is matched against Republican-turned-Democrat Harley Rouda in the 48th District where the GOP has a 10-point registration edge.

Rouda, a real estate executive, has depicted the 15-term congressman as the face of Washington gridlock and has been critical of Rohrabacher’s skepticism about global warming.

Rohrabacher was first elected three decades ago as a Reagan Republican, but he’s been campaigning as a maverick willing to defy both parties.

The Last Republican in Los Angeles County

Rep. Steve Knight is the last Republican congressman in the nation’s most populous county.

Democrats hold a registration edge in the 25th District, and Knight is in a toss-up race with Democrat Katie Hill, who is promising to end politics as usual in a district that cuts through suburbs, horse ranches and high desert in northern Los Angeles County and a small slice of Ventura County.

Knight’s family has been involved in local politics for decades — a high school is named after his father, a former legislator and test pilot.

Hill has been stressing her centrist politics: She’s a gun owner and her Republican father is a police officer who had never voted for a Democrat before her primary. Her mother, a Democrat, is a nurse.

An Indictment and Uncertainty

Republican Rep. Duncan Hunter represents the 50th District in San Diego County, which has the greatest GOP voter edge over Democrats in Southern California — 14 points.

But a 60-count federal grand jury indictment against him and his wife, alleging the couple illegally used $250,000 in campaign funds for vacations, meals and other personal expenses, reordered the race.

Hunter, who has pleaded not guilty, has called the case a witch hunt. Even with the charges hanging over him, Hunter is favored against Democrat Ammar Campa-Najjar, a 29-year-old, first-time candidate.

Hunter, A Marine combat veteran seeking his sixth term, ran an ad alleging Campa-Najjar, a Latino Arab-American, is working to “infiltrate Congress.” It falsely asserts he is supported by the Muslim Brotherhood. It also mentions his Palestinian background.

Campa-Najjar’s father served in the Palestine Liberation Organization and his grandfather was a leader of the group that orchestrated the terror attack at the 1972 Munich Olympics that killed 11 Israeli athletes.

Campa-Najjar, who was raised in San Diego by his Mexican-American mother, has had little to do with his father and his Palestinian grandfather was killed before he was born. The FBI vetted his family before giving him security clearances to work in the Obama administration.

The Next Speaker

It’s very possible that the next House speaker will call California home, regardless of who controls the chamber. House Majority Leader Kevin McCarthy, a Republican from Bakersfield, and Democratic leader Nancy Pelosi, are each heavily favored to win re-election.