Wyoming Representative Liz Cheney, Donald Trump’s fiercest Republican adversary in Congress, was defeated in a Republican Party primary on Tuesday.
She lost to a rival backed by the former US president in a contest that reinforced his grip on the party’s base.
The third-term congresswoman and her allies entered the day downbeat about her prospects, aware that Mr Trump’s backing gave Harriet Hageman considerable lift in the state where he won by the largest margin during the 2020 campaign.
Ms Cheney was already looking ahead to a political future beyond Capitol Hill that could include a 2024 presidential run, potentially putting her on another collision course with Mr Trump.
She described the loss as the beginning of a new chapter in her political career, in an address to a small collection of supporters, including her father, former vice president Dick Cheney.
“Our work is far from over,” she said on Tuesday evening.
Hinting at a presidential bid of her own, Ms Cheney later said: “I have said since January 6 that I will do whatever it takes to ensure Donald Trump is never again anywhere near the Oval Office — and I mean it.”
More than 640 kilometres away, supporters of Ms Hageman gathered at a huge outdoor rodeo in state capital Cheyenne.
“Obviously, we’re all very grateful to [former] president Trump, who recognises that Wyoming has only one congressional representative and we have to make it count,” Ms Hageman said.
The results were a powerful reminder of the Republican Party’s rapid shift to the right.
A party once dominated by national security-oriented, business-friendly conservatives such as Ms Cheney’s father now belongs to Mr Trump, animated by his populist appeal and denial of defeat in the 2020 election.
Mr Trump and his team celebrated Ms Cheney’s loss, having spent much of the day railing against the FBI on social media.
Eight days earlier, federal agents executing a search warrant recovered 11 sets of classified records from his Florida home.
Mr Trump called Ms Cheney’s loss “a complete rebuke” of the House committee investigating the January 6, 2021 attack on the US Capitol. She is the panel’s vice chairwoman.
“Liz Cheney should be ashamed of herself, the way she acted, and her spiteful, sanctimonious words and actions towards others,” he wrote on his social media platform.
“Now she can finally disappear into the depths of political oblivion where, I am sure, she will be much happier than she is right now. Thank you, Wyoming!”
Ms Cheney’s defeat would have been unthinkable just two years ago.
The daughter of a former vice president, she is from one of the most prominent political families in Wyoming.
In Washington, she was the number three House Republican, an influential voice in Republican Party politics and policy with a sterling conservative voting record.
But after the January 6 assault by a mob of Mr Trump’s supporters, Ms Cheney voted to impeach Mr Trump and made it her primary mission to ensure he never again serves in the Oval Office.
She pushed past Republican Party censures and death threats to serve as a leader on the congressional panel investigating Mr Trump’s role in the insurrection.
Ms Cheney will now be forced from Congress at the end of her third and final term in January. She is not expected to leave Capitol Hill quietly.