It was a blow for candidate Nikki Haley, who is attempting to position herself as the only candidate who can genuinely compete against front-runner Donald Trump.
The Associated Press called the race just after midnight, when "None of these candidates" was leading with about 60% of the vote. Haley trailed with 33%.
Here’s how "None of these candidates" got a win and what it means:
Nevada’s primary vs. caucus
First, it’s important to note that Nevada is holding both a caucus and primary. That’s because state law requires the state to have a primary election, but Republicans in Nevada voted in opposition to host their own caucus two days later to distribute the state’s 26 delegates.
The party also barred candidates running in the primary from running in the caucuses, forcing them to choose one event over the other.
Trump chose the caucus, so his name wasn’t on the primary ballot.
And Haley opted not to participate in Nevada’s caucus, saying she was going to instead "focus on states that are fair," which means her name was on the primary ballot.
And since Trump’s name wasn’t there, she was the only active major candidate on that ballot - meaning her biggest opponent was the "None of these candidates" option.
"None of these candidates"
Write-in votes are not allowed in the primary, but voters do have the option to vote for "None of these candidates."
Trump supporters used that option to send a message Tuesday.
Ahead of the primary, Gov. Joe Lombardo, Nevada’s Republican chief executive, endorsed Trump and publicly indicated his intent to cast his ballot for "None of these candidates." A significant number of Trump supporters appear to have followed the governor’s lead.
Haley became the first presidential candidate from either party to lose a race to "None of these candidates" since that option was first introduced.
Republican presidential candidate, former U.N. Ambassador Nikki Haley speaks during a campaign rally at the Indigo Hall and Events venue on February 05, 2024 in Spartanburg, South Carolina. (Photo by Brandon Bell/Getty Images)
Why it’s on the ballot
"None of these candidates" has appeared as an option in statewide races in Nevada since 1975.
Nevada lawmakers added "None of these candidates" as an option in all statewide races as a way post-Watergate for voters to participate but express dissatisfaction with their choices.
"None" can’t win an elected office but it came in first in primary congressional contests in 1976 and 1978.
It also finished ahead of both George Bush and Edward Kennedy in Nevada’s 1980 presidential primaries.
This story was reported from Detroit. The Associated Press contributed.