In Donald Trump's absence, Nikki Haley suffered a humiliating defeat in Nevada's Republican primary, facing no competition.
The Associated Press predicted that he received fewer votes than “none of these candidates”.
The state's governor argued against voting this way because Ms. Haley is skipping Thursday's meetings.
With presidential nominations closed, Trump is running unopposed in the polls.
With 86% of precincts reporting, Tuesday's primary vote had 63% for “nothing” and 31% for Ms. Haley.
But the race was out of control because it was rejected by the Republican Party.
All 26 state representatives who contribute to the nomination are up for grabs in the caucuses.
So “none of these candidates” winning the primary has no official impact on the race.
But the fact that the backlash against Ms Haley effectively cost her the vote reflects Mr Trump's strength.
The state legislature has two contests resulting from a Republican-Democratic conflict.
After delaying a vote in 2020, the Legislature passed legislation in 2021 to transition from caucus to primary.
A caucus is a vote that requires people to attend in person at a specific time, whereas a primary takes place regularly over several hours at a polling station.
Ms. Haley did not campaign in Nevada, choosing instead to focus on her home state of South Carolina, which votes in two weeks. And his teammates were unfazed by this rebuke from the electorate.
“Even Donald Trump knows that when you play penny slots, the House wins. We don't mind playing a rigged game for Trump,” campaign spokeswoman Olivia Perez-Cubaz said.
“We're full speed ahead in South Carolina and beyond.”
The Republican nominee, Mr Trump, is almost certain to face President Joe Biden in the November election.
Mr Biden won the Democratic primary in Nevada on Tuesday.