If campaign cash is a signal of political enthusiasm, California’s beleaguered congressional Republicans are a dour-looking bunch these days.

Already outnumbered 39-14 in the state delegation, GOP House incumbents are finding it harder than ever to raise re-election money in a strong Democratic state that’s trending even bluer.

Of the 10 Republicans targeted by the Democratic Congressional Campaign Committee in this year’s midterm elections, five of the GOP incumbents raised less money than their Democratic opponents in the final quarter of 2017 and two others abruptly announced their retirements rather than face an uncertain re-election.

In a sign of the breadth of the Republican cash crunch — and the extent of Democratic optimism — incumbents in two of the GOP’s safest seats, Rep. Doug LaMalfa of Richvale (Butte County) and Rep. Paul Cook of Yucca Valley (San Bernardino County), found themselves out-raised by little-known opponents with only a long-shot chance of winning in November.

“Historically, Republicans always win the fundraising battle,” said Drew Godinich, a spokesman for the Democratic committee. “The fact that (Democrats) have been able to out-raise them” shows how strong the challengers are.

But there’s nearly nine long months before the Nov. 6 general election, a fact Republicans are quick to point out.

Pundits eager to write off Republicans in November need to take a step back and look at the entire picture, said Jack Pandol, a spokesman for the National Republican Congressional Committee.

“Democrats aren’t talking about the massive primary costs their candidates face,” he said. Even before those Democrats have a likely one-on-one faceoff with a GOP incumbent in November, “they will have an incredibly brutal and expensive primary.”

About 70 Democrats already have filed to run against Republican incumbents in 2018, more than the total who ran in those GOP districts between 2012 and 2016, according to figures compiled by the nonpartisan California Target Book, which studies congressional and legislative races across the state.

Many of those districts feature two or more well-funded Democrats who will be struggling to be one of the two top finishers in the June 5 primary and advance to the November election.

In the 49th Congressional District now represented by retiring Rep. Darrell Issa of Vista (San Diego County), Cody Peterson, the campaign manager for Democratic challenger Doug Applegate, estimated in November that the various campaigns in the district could spend as much as $8 million in the primary alone.

That’s a lot of money, but the fall elections are likely to be even more expensive, especially since six of the Democrats’ targeted seats are in Southern California.

“By and large, the Los Angeles media market is incredibly expensive, and you have to be able to afford to run TV ads,” said Pandol, the GOP spokesman. “The Republicans have a built-in structural advantage, since as incumbents they already have better name ID” in Los Angeles, Orange and San Diego counties.

It’s also easy to underestimate just how tough a challenge Democrats face in those traditionally GOP districts, even when polls show that voters across the state are unhappy with both President Trump and Congress.

“In seven of those targeted districts, (Democratic presidential candidate) Hillary Clinton beat Trump in 2016. But in five of them, no Democrat has ever won anything,” including state Senate or Assembly seats, said Darry Sragow, a former Democratic strategist who now publishes the California Target Book. “If the past is a predictor, it’s going to be a very, very tough mountain for Democrats to climb.”

Even some Democrats are concerned that their party’s plan for California may be too ambitious, even with a flood of campaign contributions.

“We’re not going to produce seven to 10 seats,” Rep. Jared Huffman of San Rafael said on an episode of The Chronicle’s “It’s All Political” podcast. “Realistically, three to four.”

But the numbers, and especially the Republican financial figures, make the California contests intriguing for Democrats eager to flip the 24 Republican-held seats needed to take control of Congress.

GOP Rep. Tom McClintock, a five-term incumbent from Elk Grove (Sacramento County), was out-raised by two Democrats, Jessica Morse and Regina Bateson, and Morse has more money in her campaign account than McClintock.

Both Katie Porter and Brian Forde took in more money in the last quarter of 2017 than GOP incumbent Mimi Walters of Irvine (Orange County). Democrats Hans Keirstead and Harley Rouda each collected far more contributions than Rep. Dana Rohrabacher of Costa Mesa (Orange County), who was first elected to Congress in 1988. Rouda also has more cash on hand than Rohrabacher.

Then there’s GOP Rep. Duncan Hunter of Alpine (San Diego County). He raised only about $50,000 in the last quarter, behind a pair of Democrats, Josh Butner and Ammar Campa Najjar. Hunter, who was elected to replace his father in 2008, is under investigation by both the House Ethics Committee and the FBI over possible misuse of campaign funds. He already has spent about $170,000 of his campaign funds on legal expenses, with more likely to come.

With the primary still nearly four months away and the final ballot lineups not set until the March 9 filing deadline, the California Target Book found that Democratic candidates for GOP congressional seats collected $22.8 million in 2017, more than the previous six years combined.

That’s an indication of how very different the 2018 campaign will be, with recent polls showing that voters are becoming far more willing to base their decisions on local congressional races on their feelings toward Trump and the Republican-led Congress.

“Normally, long-term incumbents have access to a lot more money than challengers,” said Sragow of the California Target Book. “It’s not often (a challenger) can argue ‘I’m not the incumbent,’” and expect that will work.