House Minority Leader Kevin McCarthy is endorsing Harriet Hageman in her Wyoming primary challenge to Rep. Liz Cheney, a rare move by a sitting party leader to back an attempt to unseat one of his members. 

"I am proud to endorse Harriet Hageman for Congress," McCarthy, R-Calif., said in a statement Thursday. 

"Raised on a family ranch outside of Fort Laramie, Harriet and her family have resided in Wyoming for generations," he added. "The most successful Representatives in Congress focus on the needs of their constituents, and throughout her career, Harriet has championed America's natural resources and helped the people of Wyoming reject burdensome and onerous government overreach."

Wyoming's Harriet Hageman

Republican congressional candidate Harriet Hageman speaks with voters at an Albany County GOP breakfast in Laramie, Wyoming, on Jan. 8, 2022. (Harriet Hageman congressional campaign)

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Hageman has emerged as the most viable of several candidates trying to unseat Cheney, R-Wyo., who has earned the wrath of former President Donald Trump and many Republicans for pushing back on Trump's false claims the 2020 presidential election was stolen. Cheney's participation on the Jan. 6 Committee is also an irritant for House Republicans.

Trump endorsed Hageman last year. 

"I am very grateful for Leader McCarthy’s strong support, and I pledge that when I am Wyoming’s congresswoman, I will always stand up for our beautiful state and do the job I was sent there to do. I look forward to representing Wyoming's interests in Congress," Hageman said.

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"Wow, she must be really desperate," Cheney spokesman Jeremy Adler said in reaction to McCarthy's endorsement. 

McCarthy's public endorsement of Hageman comes after weeks of pressure from Trump-alinged members to boot her from the House Republican caucus, along with Rep. Adam Kinzinger, R-Ill., a fellow member of the Jan. 6 Committee. 

Liz Cheney

In this July 27, 2021 file photo, Rep. Liz Cheney, R-Wy., listens to testimony from Washington Metropolitan Police Department Officer Daniel Hodges during the House select committee hearing on the Jan. 6 attack on Capitol Hill in Washington. (Jim Bourg/Pool via AP, File) (AP )

Those tensions came to a head earlier this month when the Republican National Committee (RNC) censured Cheney and Kinzinger for their participation on the panel. The censure received significant backlash, especially from Senate Republicans. 

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"Shame falls on a party that would censure persons of conscience, who seek truth in the face of vitriol," Sen. Mitt Romney, R-Utah, tweeted. "Honor attaches to Liz Cheney and Adam Kinzinger for seeking truth even when doing so comes at great personal cost."

But many in the House GOP vocally supported the move. 

House Minority Leader Kevin McCarthy of Calif., speaks during his weekly press briefing on Capitol Hill, Thursday, April 22, 2021, in Washington. (AP Photo/Andrew Harnik)

"Liz Cheney has completely lost the ability to do her job of representing Wyoming as our only member of the House of Representatives," Hageman said Thursday. "The Democrats in Washington, D.C. only see her as a temporary but useful tool to achieve their partisan goals, and the Republicans want nothing to do with her. It is her responsibility to fight for Wyoming and represent our values, and she has completely abandoned that."

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Hageman said that Cheney, who has one of the most conservative voting records in Congress, is "actively damaging the Republican party – both in Wyoming and nationally – and it's time for her to go." 

"Wyoming deserves a congresswoman who will combat the disastrous Biden administration and hold them accountable for their policies which are ravaging our energy industries, destroying our sovereignty by obliterating our southern border, robbing our citizens of prosperity through catastrophic inflation, and encroaching on our constitutional rights," Hageman said. 

Though Hageman has two major endorsements in her pocket from Trump and McCarthy, Cheney has a major cash advantage in the Wyoming race. She hauled in more than $7 million in 2021 to Hageman's approximately $1 million. 

Fox News' Paul Steinhauser contributed to this report.