For California Democrats, the flood of candidates looking to unseat GOP members of Congress could be too much of a good thing.

There already are 43 Democrats, many of them with plenty of campaign cash, lined up to challenge Republicans in the top seven districts targeted by their party. And with more than seven weeks to go before the March 9 filing deadline, that number could grow.

For Democratic leaders, it’s the more the merrier, especially in a state where President Trump — and Republicans in general — are increasingly unpopular.

“I think it’s a good thing,” said Drew Godinich, a spokesman for the Democratic Congressional Campaign Committee. “As (New Mexico Rep.) Ben Ray Luján said, ‘No party ever lost an election due to too much energy and momentum.’”

The last thing Democratic leaders want is to hear discouraging words from California, which is key to their efforts to flip 24 GOP congressional seats and win back control of the House in November. The seven seats on the top of the party’s priority list — two in the Central Valley, one in Los Angeles County and four all or partially in Orange County — make up a big chunk of that wish list.

The campaign committee, invading the GOP stronghold of Orange County, has even moved its western headquarters to Irvine in an effort to show just how serious it is.

“In January 2016, the leader of the Orange County party was begging Democrats to get on board and run for Congress,” Godinich added. “Now we have multiple viable Democrats there who could compete and win.”

But that new enthusiasm comes with its own problems, said Tony Quinn, a former GOP consultant who is now an editor of the nonpartisan California Target Book, which looks at political races across the state.

“In almost every one of those (targeted) seats there’s a multitude of Democratic candidates, and many of them have money,” he said. And those people aren’t looking to spend hundreds of thousands to finish third in a primary where only the top two finishers, regardless of party, advance to the November election.

For example, in the 45th Congressional District, which Irvine GOP Rep. Mimi Walters first won in 2014, five of the seven Democrats running against her already have raised more than $250,000 each for their campaigns. That’s serious money that probably signals serious campaigns.

Expect the candidates to stake out an ideological stance and then go on the attack against their opponents, Democrats as well as Republicans, said Thad Kousser, a political science professor at UC San Diego.

The Democratic primary campaigns “may be reruns of Bernie (Sanders) versus Hillary (Clinton),” the 2016 primary fight that split Democrats across the country, Kousser said.

“Almost the only way Democrats can screw this up is with bruising primary battles that create wounds that can’t be healed,” he said.

It’s a concern, said Doug Linney, an Oakland consultant who is running Flip the 14, a group that looks to improve Democratic performance in all 14 of the state’s Republican-held congressional districts.

The group already is thinking about telling candidates that if they want help in the fall, they can’t attack fellow Democrats in the primary, he said.

“Democrats have to stay focused on the prize,” Linney added. “They need to prove they can bring about the change they want in the district. ... There is no need to attack fellow Democrats.”

But even with the prospect of a primary free-for-all, a crowded primary field is still a good thing for the party, Linney added, because each candidate brings out Democratic and independent supporters, voters who otherwise might skip a typically low-turnout midterm election.

A voter who is engaged in June is likely to stay engaged in November, he said.

“It would be nice to have one guy who can start his general election campaign in the primary, but democracy is messy,” Linney said. “We’re going to support whoever emerges from the process,” which is what he expects the losing Democrats will do.

That doesn’t mean Democratic leaders won’t have a say in the primary races.

“The DCCC (Democratic County Central Committee) reserves the right to get involved in the primaries if necessary,” Godinich said, which could mean endorsements and other backing for favored candidates. “It will be on a case-by-case basis.”

Democrats are still smarting from a 2012 San Bernardino County congressional race in which a large field split the Democratic primary vote and allowed two Republicans to finish on top and face each other in November. Party leaders are convinced that direct support for then-Redlands Mayor Pete Aguilar would have given him the congressional seat he won two years later.

This year, however, Democratic leaders, not to mention voters, might have a tough time deciding whom to support in many of the congressional races. Virtually none of the Democratic candidates has ever served in office, even on a city council or school board.

“None of these people are able to say ‘I did this’ or ‘I fixed this bridge’ or anything like it,’” said Quinn of the California Target Book. “People are going to have to choose, but they don’t have anything to compare.”

Take the campaign to unseat Rep. Dana Rohrabacher, R-Costa Mesa (Orange County), who was first elected to Congress in 1988. The leading Democrats in the race are Harley Rouda, an attorney who is in his family’s real estate business; Hans Keirstead, a doctor and CEO of a biomedical company; Omar Siddiqui, a trial lawyer and engineer; Michael Kotick, a business executive; and Laura Oatman, an architect.

But the prospect of facing a full field of Democratic challengers, politically experienced or not, already has persuaded two veteran GOP incumbents, Rep. Darrell Issa of Vista (San Diego County) and Rep. Ed Royce of Fullerton (Orange County), to hastily retire and avoid what pundits suggest could be a “blue wave” in California elections.

“If Republicans think that being a career politician is going to help a candidate these days, they haven’t been paying attention,” said Godinich, the DCCC spokesman.

In the age of Trump, who ran successfully against political business as usual, being an outsider — or even one of a pack of Democratic outsiders — is probably a strength, not a weakness.

“We know we need to concentrate our fire on Republicans, not on each other,” Godinich added. “The election is really about making the case that a Democrat is the best person for Congress.”

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