Democrats’ search for more winnable House seats is shining a brighter light on southern California, where internal tension is putting the party at risk of a November lockout.

The Congressional Progressive Caucus PAC picked its candidate on Tuesday, endorsing Democrat Ammar Campa-Najjar in the 48th District. But Campa-Najjar’s critics, including the liberal former Sen. Barbara Boxer, argue that he’s blocking a more electable candidate.

As the party splits between him and primary foe Marni von Wilpert, a San Diego city council member, Campa-Najjar’s allies worry that two Republicans could advance to the general election in a district Kamala Harris narrowly carried.

The Democratic Party’s ongoing battle over how sharply to distance itself from the unpopular Israeli government is a factor in the race. Progressives getting behind Campa-Najjar say that pro-Israel groups spending on von Wilpert’s behalf has backfired.

“If elected, Ammar will be the only Member of Congress who has lived in Gaza, where 30 members of his family, including children, have died,” said the Progressive Caucus PAC co-chairs, Reps. Pramila Jayapal of Washington, Greg Casar of Texas, and Maxwell Frost of Florida, in a statement to Semafor. “Ammar is the only candidate campaigning on a progressive agenda in this race.”

Their endorsement came after significant spending in the district by Democratic Majority for Israel on behalf of von Wilpert. The pro-Israel group opposed Campa-Najjar’s postions on the Gaza conflict, but it also worried that he could blow the election for Democrats, citing his shift to the center in 2020.

The Progressive Caucus’ endorsement was unsettling to Boxer, who backs von Wilpert. She contended to Semafor that Campa-Najjar had benefited from his longtime romantic relationship with Rep. Sara Jacobs, D-Calif., whose family has funded a super PAC helping him.

“I will tell you, the only way I think this could have happened is if his significant other, who is a congresswoman, made it happen,” Boxer said. “He has flip-flopped on the major issues they profess to care about: A woman’s right to choose, sensible gun rights, and Medicare for All. I was the Number One liberal in the Senate. I know a phony when I see a phony.”

Campa-Najjar California’s district got redrawn to include parts of Palm Springs in north San Diego County; as a result, it could be harder for Republicans to win. Rep. Darrell Issa, R-Calif., retired after voters approved the new district lines.

“As the son of a Palestinian immigrant and a working-class Latina mother, I know what it’s like to grow up having to choose between a gallon of milk and a gallon of gas,” Campa-Najjar told Semafor on Monday, before going to a California Islamic center targeted by a mass shooter to show his support for victims. “I’m a proud progressive.”