In the races for the handful of California’s remaining GOP congressional seats, the nastiest battles could be between the Republicans.

The GOP holds just seven of California’s 53 House seats, and one of the party’s seven incumbents, Rep. Duncan Hunter of Alpine (San Diego County), faces a January trial on 60 felony counts related to alleged misuse of campaign contributions. A Survey USA poll done last week for the San Diego Union-Tribune found the four-term congressman running fourth, behind a Democrat and two Republicans.

Four other local Republicans who were challenging Hunter ended their campaigns and endorsed former GOP Rep. Darrell Issa, who had represented a neighboring district, when he jumped into the race last month.

Carl DeMaio, a former San Diego city councilman turned conservative talk show host, is also going after Hunter. DeMaio says he already has raised $1.3 million for his campaign. He’ll need every penny to take on Issa, who with a net worth of about $250 million was the wealthiest member of Congress during his 18 years in Washington.

DeMaio is already taking shots at both Hunter and Issa, arguing that Hunter can’t get re-elected and that Issa “is a politician who epitomizes what is wrong with career politicians.” He noted that Issa decided not to run for re-election last year in a district that straddled Orange and San Diego counties. The race turned into a Democratic takeaway when it was won by Mike Levin.

Issa “quit his congressional seat at a time when the party needed him to fight,” DeMaio said.

In opening his campaign, Issa called Hunter’s legal problems regrettable and said the district needs a congressman who could devote all his efforts to his work.

“I believe I have the history, the skills, the seniority and the capability to hit the ground running not just for this district, but for California,” Issa said.

Democrat Ammar Campa-Najjar ran a surprisingly strong campaign against Hunter last year, losing 52% to 48% in a district where Republicans hold a 39%-to-27% registration edge.

The former Obama administration aide is back for another try. As of June 30, he had $479,914 in campaign cash, compared with $296,511 for Hunter.

But the incumbent is confident that he’ll be vindicated at his trial in January and go on to be re-elected.

“I’m one of the only guys that won last time around and that was under indictment,” Hunter told a San Diego television station.

Hunter might not make it to election day. He wouldn’t automatically be ousted from office if he is found guilty, but other members of Congress with felony convictions have typically resigned. And if a plea deal is made, resignation is almost always a requirement.

Here’s a look at the other GOP-held congressional seats in California. It’s not a long list:

Open-seat brawl: In a San Bernardino County congressional district so red that no Democrat made it into last November’s general election, GOP Rep. Paul Cook announced last month that he is leaving Congress to run for county supervisor. He immediately endorsed GOP Assemblyman Jay Obernolte of Big Bear Lake, who had his “Elect Jay” website up almost before Cook finished his announcement.

But Obernolte’s hopes for a walkover disappeared when Jeremy Staat, a former NFL player and motivational speaker, announced that he would move from Bakersfield and seek the open seat as a Republican.

North state rematch: Democrats are hoping a rematch in a rural, sparsely populated district in northeastern California goes better than the 2018 election, when GOP Rep. Doug LaMalfa of Richvale (Butte County) beat Democrat Audrey Denney, an agriculture educator, 55% to 45%. One encouraging sign for Democrats: Denney, a Chico resident, has a bit more cash on hand than the incumbent.

Money problems: Rep. Tom McClintock is another Republican incumbent with potential money issues. He won a fifth term last year in a district extending from the eastern Sacramento suburbs to Truckee and south to Sequoia National Forest, 54% to 46%. But that was his tightest race since his first in 2012, and in this year’s second quarter, Democratic challenger Brynne Kennedy, a Roseville entrepreneur, outraised him by better than 2 to 1.

Nunes ready: Tulare Rep. Devin Nunes is a favorite target of liberal Democrats nationwide, and he faced a tough contest before winning re-election last November. But he has a ton of money in the bank — $5.6 million as of June 30 — and raised nearly 10 times what his best-financed opponent, Democrat Phil Arballo, did in the second quarter.

GOP leader safe: Bakersfield Rep. Kevin McCarthy, the top Republican in the House, has $3.5 million available for his campaign, compared with zero reported for his lone Democratic opponent.

No worries: Another safe re-election bet is Rep. Ken Calvert of Corona (Riverside County). He has nearly $700,000 in the bank, compared with $4,600 for his top Democratic challenger.

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