Nikki Haley has vowed to forge ahead with her White House campaign after a humiliating defeat in the Republican primary in Nevada.
She received fewer votes than "None of these candidates" by a large margin on Tuesday, despite facing no competition in the absence of Donald Trump.
The Nevada governor advocated voting in this way as a protest because Ms Haley is skipping Thursday's caucuses.
Mr Trump is meanwhile closing in on the party's presidential nomination.
The fact there are two contests is a result of a dispute between the Republican Party and Democrats in the state legislature.
The legislature passed a law in 2021 to switch from caucus to primary after voting delays in 2020.
A caucus is a vote that requires people to attend in person at a specific time whereas a primary is held in the usual way at a polling station over a number of hours and through early voting.
Ms Haley won just 31% in Tuesday's contest, well behind the 63% of the ballots cast for "none of these candidates", according to Nevada election officials
But the contest is non-binding because it has been disavowed by the Republican Party.
Following the loss, Ms Haley took to X, formerly Twitter, to criticise her party.
"Republicans keep doing the same thing and getting the same result: chaos," she wrote. "That's the definition of insanity."
She listed three major developments this week, including the news that the party's chairwoman had offered to resign in a meeting with Mr Trump, the party's inability to pass legislation in the House of Representatives and a court's finding that Mr Trump does not have immunity from prosecution.
"A vote for Trump is a vote for even more chaos," she wrote.
Ms Haley did not campaign in Nevada and chose instead to focus on her home state of South Carolina, which votes in just over two weeks. The Nevada result left her team undeterred.
"Even Donald Trump knows that when you play penny slots, the house wins. We didn't bother to play a game rigged for Trump," said Haley campaign spokeswoman Olivia Perez-Cubas.
"We're full steam ahead in South Carolina and beyond."
However, a person close to Ms Haley, who asked to remain anonymous, told Reuters news agency the results in Nevada were "an embarrassing situation".
The Trump campaign mocked her loss.
"It has been a while since the political world was treated to such a humiliating, embarrassing, and utterly overwhelming defeat than Nikki Haley suffered yesterday in Nevada," spokesman Steven Cheung wrote in a statement.
All of the state's 26 delegates that contribute to the nomination are up for grabs in the caucuses.
So the victory for "none of these candidates" in the primary will have no official impact on the race.
But it reflects the strength of Mr Trump that the backlash against Ms Haley resulted in her effectively losing the vote.
Ms Haley could still be declared the victor by the secretary of state's office if only named candidates are counted, reports the New York Times.
The Republican nominee, almost certain to be Mr Trump, will probably face President Joe Biden in November's election.
Mr Biden won the Democratic primary in Nevada on Tuesday.
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