WASHINGTON — Republican Mike Garcia was leading Democrat Christy Smith on Wednesday in a California special election for the House seat vacated by Rep. Katie Hill.

With 76 percent of the vote counted, Garcia had 56 percent, or 78,701 votes, and Smith had 44 percent, or 62,054 votes.

NBC News projects the race is too early to call. More votes — most were mailed in — are expected to be tallied on Wednesday.

Democrats flipped California’s 25th Congressional District in 2018 — a district Donald Trump lost by seven points in 2016. A year later, Hill resigned amid an ethics investigation into allegations of a relationship with a staffer, which Hill denies, and after nude photos of her were published online without her consent.

Now Republicans are bullish that Garcia can win the seat back.

The winner will fill out the remainder of Hill’s term and then Smith and Garcia will face off again in November’s general election in a bid for the subsequent two-year term starting in 2021.

The coronavirus epidemic has created more uncertainty in the race, with most voters expected to vote by mail after Democratic Gov. Gavin Newsom ordered the state to send ballots to every registered voter’s home.

The vote-by-mail process, one that California had been increasingly embracing even before the pandemic, hasn’t been without controversy.

Trump raised unfounded accusations of voter fraud last month when he endorsed Garcia on Twitter and added, “Turn your Ballots in now and track them, watching for dishonesty.”

Voters were able to cast ballots at a handful of sites if they didn’t vote by mail. But Trump and Garcia criticized the late decision to add a site in Lancaster, a city with a significant minority population. Trump called it proof that the Democrats were pushing for a “rigged election,” while Democrats pointed to the support of the city’s Republican mayor for adding a polling place.

Meanwhile, former Vice President Joe Biden easily defeated Sen. Bernie Sanders, I-Vt., in the Nebraska Democratic primary on Tuesday, NBC News projected. With 92 percent of the vote in, Biden was leading Sanders by 77 percent to 14 percent and expected to net 27 delegates.

Tuesday’s other special House election took place in Wisconsin’s 7th Congressional District, one that Trump won easily in 2016 and that Republicans were expected to hold. The seat was vacated last year when Republican Sean Duffy retired, pointing to impending health issues with his then-unborn child.

NBC News projects that GOP state Sen. Tom Tiffany will win there against Tricia Zunker, who was hoping to become Wisconsin’s first Native American member of Congress.

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One Democratic congressional primary stood out among the rest of the races Tuesday — the clash between Kara Eastman and Ann Ashford in the 2nd Congressional District around Omaha, Nebraska. Eastman won the contest easily, by 30 percentage points, according to the Associated Press.

Ashford’s husband, Brad, held the seat for one term but lost to Republican Don Bacon, the current representative, in 2016. His 2018 comeback bid was foiled by Eastman, who won the Democratic primary that year but ultimately fell short to Bacon by 2 points in the general election.

Eastman had the backing of prominent progressive Democrats like Rep. Alexandria Ocasio-Cortez of New York and supports “Medicare for All,” while Ashford has the backing of two former Nebraska Democratic senators and has cast her plans as more “realistic.”