Ken Calvert

Representative Young Kim, a battle-tested Orange County Republican, has ousted veteran Democrats in tight races, but she’s actually a “Trump-hating liberal,” one television advertisement proclaims.

Representative Ken Calvert, a Republican fixture in nearby Riverside County, is a longtime thorn in the side of Democrats, but he’s guilty of “sabotaging President Trump’s agenda,” a different ad declares.

Some Republicans are distancing themselves from Mr. Trump these days, given his flagging approval ratings and an unpopular war with Iran that has divided the MAGA base. But not Ms. Kim or Mr. Calvert, two G.O.P. incumbents forced to face off for political survival after Democrats scrambled their House districts in a gerrymandering push last fall.

Squaring off in a redrawn and heavily Republican district that combines their turf, Ms. Kim, 63, and Mr. Calvert, 72, longtime colleagues in the House, are both proudly touting their conservative bona fides while accusing each other of being out of step with MAGA voters.

For all the hand-wringing over fractures in Mr. Trump’s America First coalition and his waning influence over some corners of the Republican Party, the contest shows that plenty of conservatives remain eager to align closely with the president.

Both members say they maintain a cordial relationship when they see each other on Capitol Hill. But as a June primary approaches, there is little to call cordial in their campaign rhetoric. Mr. Calvert, in particular, has blasted out a series of emails portraying Ms. Kim as a RINO: a Republican In Name Only.

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