Democratic plans to target half of California’s 14 Republican members of Congress in the 2018 midterm elections represent a high-stakes bet that President Trump’s continuing unpopularity in the state will filter down to even the strongest GOP candidates.

There’s going to be a backlash in the state from voters still outraged that the GOP businessman was elected at all and others upset with Trump’s plans for the nation, said Robin Swanson, a spokeswoman for the California Democratic Party.

“Donald Trump lost California by more than 4 million votes,” she said. “When Republicans align themselves with his unpopular policies, it’s going to stick.”

Democrats plan to spend the money to make that happen.

California’s seven GOP targets represent nearly a third of the 24 seats Democrats need to take control of the House and return San Francisco Rep. Nancy Pelosi to the speakership. Nationwide, the Democratic Congressional Campaign Committee has identified 59 Republican-held districts they believe can be flipped.

There are some familiar names on the Democratic hit list. Jeff Denham of Turlock (Stanislaus County), David Valadao of Hanford (Kings County) and Steve Knight of Lancaster (Los Angeles County) were all targets in 2016, and Darrell Issa of Vista (San Diego County) barely held on to his seat.

Back to Gallery California Democrats focus on normally safe GOP House seats 7 1 of 7 Photo: Chip Somodevilla, Getty Images 2 of 7 3 of 7 Photo: Bill Clark / CQ-Roll Call,Inc. 4 of 7 Photo: Bill Clark / CQ-Roll Call 2016 5 of 7 Photo: Bill Clark / CQ-Roll Call 6 of 7 Photo: Bill Clark / CQ-Roll Call,Inc. 7 of 7 Photo: Bill Clark, CQ-Roll Call,Inc.













New additions to the Democratic list are a trio of Orange County Republicans, Ed Royce of Fullerton, Mimi Walters of Irvine and Dana Rohrabacher of Costa Mesa.

But it’s a long way to November 2018, cautioned Tony Quinn, a former GOP redistricting consultant and current co-editor of the California Target Book, which follows political races in the state.

“We’re looking at an election more than a year off,” he said. “In 2009, for example, (President Barack) Obama looked strong, passing the stimulus package” and moving most of the way to the Affordable Care Act, which he signed in March 2010.

But by November 2010, his popularity was plummeting and the midterm election brought what Obama admitted was “a shellacking,” with Democrats losing 63 seats and control of the House.

“It’s pretty early to draw too many conclusions,” Quinn added.

Still, even with midterm elections more than 18 months away, Republicans are finding plenty to worry about.

Last Tuesday, when Kansas Republican Ron Estes won a special election for the seat Mike Pompeo left when he was named CIA chief, Trump tweeted that it was a “great win,” praising Estes for “easily winning the congressional race against the Dems, who spent heavily and predicted victory.”

File that under “alternative facts.”

Estes’ 53 percent to 46 percent victory over little-known Democrat James Thompson came in a hard-core Republican district that Pompeo won by 31 percentage points in November and that Trump carried by 27 percentage points.

And to the dismay of progressive Democrats, while the national party operation provided some phone banking in the campaign’s waning days, it didn’t spend much on the race, which was viewed as a likely slam dunk for the GOP.

The news for Republicans could be even worse come Tuesday in Georgia, where Democrat Jon Ossoff, a 30-year-old former congressional aide, is running for a suburban Atlanta congressional seat that hasn’t gone Democratic since 1978. He’s one of 18 candidates for the seat former GOP Rep. Tom Price gave up when he was confirmed in February as secretary of health and human services.

Yet Ossoff is leading in the polls, with an outside chance of collecting the 50 percent plus one votes needed to avoid a June runoff election. And he’s pulled in more than $8.3 million in contributions, most from donors outside Georgia enamored with his anti-Trump rhetoric.

A Democratic win Tuesday would set the alarm bells ringing for GOP leaders, warning them that Trump’s growing unpopularity could transform even the most solidly Republican districts into toss-ups come November 2018.

Republican leaders don’t see that happening in California, where they argue that GOP officeholders will run on their own accomplishments and not as reflections of Trump.

“We feel confident about our chances in California,” said Jack Pandol, a spokesman for the National Republican Congressional Committee. The GOP incumbents “have their own individual identities ... and are well-known for the local issues they have championed.”

They’ve also been tested in political fire, he added. While the two Central Valley congressmen, Denham and Valadao, are in Democratic majority districts, for example, they’ve turned back numerous efforts to oust them. And the Orange County Republicans have run up big numbers in their districts.

“They have a proven ability to win in all political contexts,” Pandol said. “And their constituents know that.”

There’s also the hope that Trump, like former GOP Gov. Arnold Schwarzenegger, won’t really have much effect on other California ballot contests.

While Schwarzenegger was re-elected in a landslide in 2006, Democrats swept all but one of the other statewide offices and didn’t lose a seat in the Legislature. And while Trump was steamrolled in 2016, not a single congressional seat changed parties.

“Like Arnold, voters might see Trump as someone unique and not as a Republican,” Quinn said.

But with Trump desperate for political wins, the pressure will be on all GOP members of Congress to back the president, regardless of how that support might play back home.

“The biggest problem California Republicans face is casting bad votes,” Quinn said. “You get a sense that some Republicans in the House are getting more gun-shy, not wanting to cast votes that might put them in danger.”

That’s already being seen in California. Issa, whose lifetime rating by the national League of Conservation Voters is 4 percent — and 3 percent in 2016 — now says he opposes Trump’s call for deep cuts in the Environmental Protection Agency. And of the seven targeted GOP representatives, five refused to say how they stood on the Republican health care plan, which was pulled before it came to a vote in the House.

But while Democrats appear, at least for now, to have the upper hand in California’s upcoming congressional battles, they have to be careful not to overreach, Quinn said.

Much of the loudest opposition to Trump is coming from progressives, who argue that Democrats need to oppose Trump by moving strongly to the left with candidates more to the Bernie Sanders side of the party. But that might not be a path to victory in California.

“There’s a real danger for the Democrats if they nominate people too progressive,” Quinn said. The Republican districts being targeted “aren’t downtown San Francisco. Instead, they’re downtown Modesto, downtown Hanford and the suburbs of Orange County.”

John Wildermuth is a San Francisco Chronicle staff writer. Email: jwildermuth@sfchronicle.com Twitter: @jfwildermuth