Jim Marchant, a vocal election denier and Trump ally who lost his bid for Nevada’s secretary of state in last year’s midterm elections, declared his candidacy on Tuesday for the Senate in a swing state contest that could decide control of the chamber in 2024.
Mr. Marchant, a Republican, is seeking to challenge Senator Jacky Rosen, a moderate Democrat who is in her first term. No other high-profile Republicans have entered the contest so far.
During last year’s midterm elections, Mr. Marchant helped organize a national “America First” slate of secretary of state candidates, a group of right-wing election deniers whose campaigns centered on re-litigating baseless voter fraud claims. All but one of the candidates were rejected by voters.
The once-obscure election oversight post has taken on heightened significance since the 2020 election. In Mr. Marchant’s race, he did not appear to concede.
Mr. Marchant, 66, a former one-term assemblyman, was also part of Nevada’s alternate slate of pro-Trump electors who sought to overturn Joseph R. Biden Jr.’s victory in the state in 2020. He refused to accept the results that same year in his race for Congress, unsuccessfully challenging them in court.
“There’s nothing more precious than our freedom and personal liberty,” Mr. Marchant said on Tuesday, speaking at a Las Vegas church known for having tested Nevada’s pandemic stay-at-home orders in court in 2020. “And I’m running for United States Senate to protect Nevadans from the overbearing government, from Silicon Valley, from big media, from labor unions, from the radical gender change advocates, where Jacky Rosen has failed you.”
In a statement on Twitter on Tuesday, Ms. Rosen cast Mr. Marchant as an extremist.
“Nevadans deserve a Senator who will fight for them, not a MAGA election denier who opposes abortion rights even in cases of rape and incest,” she wrote. “While far-right politicians like Jim Marchant spread baseless conspiracy theories, I’ve always focused on solving problems for Nevadans.”
Mr. Marchant was joined on Tuesday by the political strategist Dick Morris, who Mr. Marchant said would be working as a general consultant on his campaign. Mr. Morris, who preceded him onstage, also repeated false claims about election fraud.