WYOMING (BLOOMBERG) - Republican Representative Liz Cheney called on Americans to unite across party lines to keep Mr Donald Trump from winning the White House again following her crushing defeat to a primary challenger backed by the former president.

Ms Cheney, who has served three terms in Wyoming's sole seat in the House of Representatives, vowed to do whatever it takes to block Mr Trump's path after losing to conservative lawyer Harriet Hageman in Tuesday's (Aug 16) Republican primary.

Early Wednesday (Aug 17), Ms Cheney told NBC she was "thinking about" a 2024 presidential run as she launched a new political organisation called "The Great Task", a nod to President Abraham Lincoln's famous Gettysburg address.

"That's a decision that I'm going to make in the coming months," she said. "It is something that I'm thinking about."

In acknowledging defeat Tuesday, Ms Cheney warned that the Jan 6 US Capitol insurrection and the refusal of Mr Trump and other Republican leaders to tamp down the rage behind it put the nation at risk.

"Our nation is barreling once again toward a crisis of lawlessness and violence," she said, putting the blame squarely on Mr Trump. "I have said since Jan 6 that I will do whatever it takes to ensure Donald Trump is never again anywhere near the Oval Office, and I mean it."

In addition to her new PAC, Ms Cheney will have a public forum for her campaign against Mr Trump as vice-chair of the committee investigating the former president's role in the Capitol insurrection until she leaves Congress in January.

Story of Liz

Ms Cheney was a rising Republican star until she stood up to Mr Trump. After she voted to impeach Mr Trump in the aftermath of the attack on the Capitol by a mob of his supporters, the political costs for Ms Cheney's defiance mounted.

The Wyoming Republican Party voted to censure her and asked her to resign. Then, she was removed as the third-ranking House Republican leader by her colleagues, who accused her of abandoning the party.

That culminated in her loss Tuesday to Ms Hageman by a two-to-one margin with half the votes counted.

Citing Lincoln, the Republican president who steered the US through the Civil War, Ms Cheney said no office was worth betraying the democratic principles the US was built on.

"Two years ago, I won this primary with 73 per cent of the vote. I could easily have done the same again," she said. "But it would've required that I go along with President Trump's lie about the 2020 election. It would've required that I enabled his ongoing efforts to unravel our democratic system and attack the foundations of our republic. That was a path I could not, and would not, take."

In her speech, Ms Hageman said, "Wyoming has put the elites on notice: We are no longer going to tolerate representatives who don't represent us."

Wyoming is a reliably Republican state, so the winner of the GOP primary is all but assured a general election victory.

Mr Trump called Ms Hageman's victory a "complete rebuke" of the Jan 6 committee and a "wonderful result for America" in a posting on his Truth Social website.

Trump's grip

Ms Cheney's loss is the latest illustration of Mr Trump's grip on the Republican Party. Just two of the 10 House Republicans who voted to impeach Mr Trump after the US Capitol insurrection last year survived their primaries to make it to the ballot in November's general election.

Ms Cheney is the fourth to be defeated and four are retiring. Among those 10, Ms Cheney was the most prominent and persistent in rebutting Mr Trump's election lies and in making the case that the Republican Party had to hold him accountable for the Jan 6 Capitol attack and must reject him as a threat to the nation's democratic order and the Constitution.

"At the heart of the attack on Jan 6 is a willingness to embrace dangerous conspiracies that attack the very core premise of our nation, that lawful elections reviewed by the court when necessary and certified by the states and electoral college determine who serves as president," Ms Cheney said.

Ms Cheney, a one-time Trump backer and a conservative on most social and security policy issues, had been openly appealing to Wyoming Democrats to temporarily switch their parties and vote for her in the Republican primary.

But the prospect of there being enough Democrats doing that was always a long-shot.

What now, Liz?

Mr James King, a University of Wyoming political scientist, said he does not know whether there is a path for Ms Cheney to jump into the 2024 GOP presidential nomination race.

Ms Cheney's policy positions match closely with the most conservative elements of the Republican Party. But, he said, "the sin of not supporting former President Trump on issues related to the 2020 election might lead Trump supporters in the electorate to choose a conservative candidate who did support Trump."

Ms Kathryn Valido, a Democrat in Cheyenne who voted for Ms Cheney, said Ms Cheney sparked some hope that the country's partisan gap can be closed.

"Liz represents something our representative government sorely lacks; she has put our country and Constitution ahead of politics," Ms Valido said.

She said the fact that she and other Democrats crossed over and joined some Republicans to support Ms Cheney "tells me her brand of leadership is perhaps a map toward bipartisanship".