The last time Mark Armstrong saw Liz Cheney was three years ago. The Wyoming Republican organizer pulled the congresswoman aside after she gave a speech at a local party. He told her that he hoped one day she would become the first woman to be elected president of the United States. So it was with such frustration and anger that she watched her vote to impeach Donald Trump for the January 6, 2021 attack on the US Capitol. “Liz has one of the most conservative records in Congress. She is not liberal. It’s too far to the right,” said Mr. Armstrong, a 65-year-old geotechnical engineer in Laramie, Wyo. “But I can’t vote for her, I can’t support her after January 6.” Mrs. Cheney’s journey from Republican rising star to party renegade may come to an end Tuesday in the primary for this deep-red state’s lone seat. Polls show her trailing Trump-backed challenger Harriet Hagman by more than 20 percentage points. The vote is a major turning point for Republicans. If a conservative as streaky as Ms. Cheney is banished to the political wilderness, it will cement Mr. Trump’s power in the party. It all unfolds as the former president mulls a comeback bid in 2024 and a week after the FBI raided his Mar-a-Lago estate in one of a widening criminal probe into his conduct. Rather than play down her disagreement, Ms. Cheney has campaigned steadily on her work with the congressional committee investigating Mr. Trump’s efforts to overturn his re-election loss. In a series of hearings this summer, the committee presented bombshell evidence that he worked to foment the rebellion. “America cannot remain free if we abandon the truth. The lie that the 2020 presidential election was stolen is insidious,” Ms. Cheney said in her latest campaign ad. “History has shown us time and time again how these kinds of poisonous lies destroy free nations.” Around this western state of prairie, desert and mountains – where 600,000 people are spread over a landmass the size of Britain – many Republicans said they hoped Ms Cheney’s defeat would signal a purge of those unfaithful to Mr Trump. . “I think the election is going to sweep out all the RINOs — Republicans in name only,” said Zaida Zoller, a 69-year-old Buffalo rancher. Whenever she sees one of Ms. Cheney’s campaign signs, Ms. Zoller said, she yells “Liz Cheney is a traitor” out her car window. “It’s not the Republican Party anymore, it’s the Trump Party,” said Susan Martin, 58, a retired teacher wearing a Hageman sign in the sagebrush plain that surrounds her rural gray home. “You know who really should have been blamed? Every Democrat in office who stole the election,” said Terri Yeadon, a 50-something voter in Casper. Added her son Nathaniel, 21: “Liz Cheney should burn in hell.” For the congresswoman’s remaining supporters, such a debate is the latest indicator of the country’s slide toward authoritarianism in the age of Trump. “He is dishonest. He is arrogant. He will do anything to get the job done. Cheney is standing up for our constitution and we hope he will be brought to justice,” said Richard Wilson, 77, a retired heavy-engine engineer and lifelong Republican. Standing on the steps of his bungalow in Casper, an oil town of 59,000, Mr. Wilson pointed to two houses on the block that had had Cheney signs stolen from their lawns last week. Another sign a few streets away was vandalized with spray paint, Ms. Cheney’s name crossed out and the words “don’t vote RINO” underneath. Randy Ford, 70, one of the few voters still undecided ahead of the primaries, said he supported Mr. Trump through two elections, excited by his policies to cut taxes and renegotiate trade deals. However, Mr Ford soured on the former president when he tried to overturn his 2020 defeat. “I wish the Justice Department would jump in there and help the committee sort this all out,” Mr. Ford, a 70-year-old retired financial planner, told a gathering of Republicans in a Casper park. “If Trump is guilty, I certainly wouldn’t want him running again. What would we tell our children? That it’s okay to cheat and lie?’ No one better illustrates the party’s coalescence around Mr. Trump than Ms. Hageman. In 2016, he referred to the billionaire as “racist and xenophobic” in emails leaked to the New York Times. Now, she describes him as the “greatest president of my life” and the 2020 election as “rigged.” Ms. Cheney’s slim hope for survival rests on a Wyoming election rule that allows voters to change their party affiliation at any time before an election. Her campaign actively encouraged Democrats to temporarily join Republicans in supporting her. It’s a particularly ironic strategy given Ms. Cheney’s history as a bulwark of Republican orthodoxy: anti-abortion, pro-gun and pro-fossil fuel in a state where oil, gas and coal dominate the economy. In Congress, Ms. Cheney voted with Mr. Trump more than 90 percent of the time. Jane Ifland, a Casper social justice activist, has been on the opposite side of nearly every issue from Ms. Cheney. He even remembers confronting the congresswoman about single-payer health care at an open house a few years ago. But in an advance poll last week, Ms. Ifland voted Republican for the first time in her 77 years. “I was crying about it,” she said. “I certainly wasn’t voting for any of the policies that Cheney supports, but I voted because I want to continue living in a democracy.” There may not be enough Democrats to make a difference in Wyoming, which Mr. Trump carried with nearly 70 percent of the vote in 2020. But it has sparked dark debate among Republicans about election fraud. At a local party meeting in Laramie, organizers expressed fears that election workers are encouraging Democrats to change their voter registrations. They warned that Democrats might bus people out of state to vote illegally. “We’re going to make sure that caravans don’t come across that border,” said Katrina Cox, 52, the county party’s vice-chairwoman. “The intersection vote is a big problem. I think it’s a scam.” Others in the room said Ms. Cheney’s problems in the state predated the no-confidence vote. Having spent much of her life in Washington, she has faced questions about her ties to Wyoming since her first election in 2016. “I have heard Harriet Hageman speak four times in the last year. I’ve never met Liz. That’s a problem,” said Brandon Newman, 37, who works as a trade school instructor. Ms. Cheney’s status as local political royalty cuts both ways. Her father, former Vice President Dick Cheney, ran an ad for his daughter denouncing Trump as a “coward” and the biggest threat to democracy in US history. But as the chief architect of the disastrous invasion of Iraq, he is a persistent reminder of one of the reasons so many Republicans rejected the party establishment and embraced Mr. Trump in the first place. Amid an avalanche of threats for her opposition to Mr. Trump, Ms. Cheney has kept a low profile in the state. She does not organize public campaigns, instead opting for private gatherings in the homes of her supporters. A police bodyguard has been assigned to her. Her end game is currently unclear. In speeches and interviews, she has seemed to implicitly concede that her opposition to Mr. Trump will cost her her seat in the House, fueling speculation that her real goal is to mount a presidential bid in 2024. In her latest ad, however, she explained her decision as a simple commitment to stop Mr. Trump, whatever the cost. “Millions of Americans across our nation – Republicans, Democrats, independents – stand united in the cause of freedom,” he said. “We are stronger, more committed and more determined than those who are trying to destroy our democracy. This is our great task and we will win.” Your time is valuable. Have the Top Business Headlines newsletter conveniently delivered to your inbox morning or night. Sign up today.