LOS ANGELES (AP) — A California legislator backed by former President Donald Trump and a county sheriff promising to fight for tougher border security are matched in a special election Tuesday to decide who will complete the remainder of the term of deposed former House Speaker Kevin McCarthy, which runs through January.

State Assembly member Vince Fong and Tulare County Sheriff Mike Boudreaux, both Republicans, are vying for the vacant 20th Congressional District seat in the state’s Central Valley farm belt. The district, which cuts through parts of Bakersfield and Fresno, is the most strongly Republican House seat in heavily Democratic California.

Because of Trump’s involvement, the race will be watched as a possible proxy vote on the former president’s clout as he heads toward an all-but-certain matchup against President Joe Biden in November.

Trump endorsed Fong in February, calling him “a true Republican.” Boudreaux’s supporters include Richard Grenell, a former acting director of national intelligence in the Trump administration, and Republican state Sen. Shannon Grove of Bakersfield, Fong’s home turf.

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Republicans occupy only 11 of the state’s 52 U.S. House seats. With the district once held by McCarthy remaining in GOP hands, it will give Republicans 12 seats in the state delegation and boost the party’s fragile edge in Congress by a single vote.

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There are 217 Republicans in the House, 213 Democrats and five vacancies, including McCarthy’s former seat.

The special election only covers the time remaining in McCarthy’s term. Fong and Boudreaux will reprise their contest again in November for a full, two-year term in the district, though the winner of the special election will gain the advantage of incumbency.

A light turnout is expected. Mail-in voting for the special election began last month.

Some voters might be confused, since Fong and Boudreaux already have appeared on two House ballots this year — the March 5 statewide primary for the full House term, and the March 19 primary in the special election to fill out McCarthy’s term.

The two conservative Republicans and Trump supporters occupy much of the same policy terrain. Boudreaux has been spotlighting his decades of law-and-order experience and is promising to harden the nation’s porous border. Fong also promises to “end the chaos” at the border with Mexico while prioritizing water and energy needs in the farm belt.

Fong, a onetime McCarthy aide who also has the former speaker’s endorsement, entered the contest with advantages beyond endorsements from Trump and McCarthy.

Fong carried 42% of the vote in the March primary election, Boudreaux nearly 26%, with the remainder divided among other candidates. Fong hails from the most populous part of the district, Kern County, and he has outraised the sheriff by about 3-to-1 in campaign funds, according to federal records through the end of March.

McCarthy’s dramatic fall in the House — he is the only speaker in history to be voted out of the job — left behind a messy race to succeed him that exposed rivalries within his own party. He has worked behind the scenes to promote Fong’s candidacy — a political action committee linked to McCarthy steered over $700,000 into the 20th District contest to boost Fong’s campaign.

McCarthy resigned last year after being ousted in the House.