House Republican leader Kevin McCarthy complained Thursday that there’s “a lot of fraud” when it comes to voting by mail. If that’s true, he might want to be worried about his first-place finish in his San Joaquin Valley district’s primary March 3.

The Bakersfield Republican attacked Democrats for holding up a proposed coronavirus relief bill, partly because they want to add as much as $2 billion to help states make voting safer and easier in November, including by expanding mail elections.

“You want to hold a bill up because you want to change election law in November, that somehow you think that gives you benefit?” McCarthy said in a call with reporters. “That’s disgusting.”

McCarthy was echoing President Trump, who complained again Tuesday that voting by mail was dangerous for the country.

“Mail ballots, they cheat,” the president said. “OK, people cheat. Mail ballots are a very dangerous thing for this country because they are cheaters.”

Trump has repeatedly made baseless allegations of widespread voting fraud in the past, and said most of the supposed cheaters are Democrats.

But if McCarthy is looking to bash voting by mail, he needs to turn his sights closer to home.

In Kern County, which accounts for most of McCarthy’s 23rd Congressional District, nearly 70% of the voters now opt to receive mail ballots in every election.

In last month’s primary, McCarthy routed Democrat Kim Mangone by better than 2 to 1. According to election officials, 72% of Kern County’s turnout was from mail ballots.

If Democratic efforts to boost the number of mail ballots would ensure that “you’d never have a Republican elected in this country again,” as Trump suggested in a recent Fox News interview, McCarthy can’t prove it by Kern County.

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