Trump picked up his third straight victory last night in the Nevada caucuses.
"Now we are winning winning, winning the country," Trump said, claiming victory to a crowded hall.
Marco Rubio and Ted Cruz battled it out for second, with Rubio taking the spot with less than 2,000 votes ahead of Cruz. Cruz says his third-place finish showed progress.
"We are one step closer to turning the pages on the failures on the Obama-Clinton disaster," Cruz said.
Meanwhile, Rubio touted his establishment candidacy for a general election win.
"I am a conservative that can unite this party," Rubio said.
The candidates were fanning out to their next targets of opportunity as the lights went out in Las Vegas: Trump was campaigning today in Virginia, then on to Texas and Oklahoma. Rubio and Cruz both headed for Texas.
Entrance polls in Nevada captured the sentiment propelling Trump's insurgent campaign: Six in 10 caucus goers said they were angry with the way the government is working, and Trump got about half of them.
Cruz, a fiery conservative popular among voters on the GOP's right, had finished a disappointing third in South Carolina after spending much of the past two weeks denying charges of dishonest campaign tactics and defending his integrity. Nevada raises more questions about his viability.
But Cruz harked back to his win in Iowa's leadoff caucuses to remind supporters that his is "the only campaign that has defeated Donald Trump is this campaign."
The election calendar suggests that if Trump's rivals don't slow him by mid-March, they may not ever.
Trump won 14 delegates in Nevada, Rubio won seven and Cruz won six. John Kasich and Ben Carson each go one, with one delegate left to allocated.
Overall, Trump has 79 delegates, Cruz has 16 and Rubio has 15. John Kasich has five delegates and Ben Carson has three. It takes 1,237 delegates to win the Republican nomination for president.
Trump, in his victory speech, took on the notion advanced by both Rubio and Cruz that if more GOP candidates drop out of the race, they'll coalesce around an alternative.
"They keep forgetting that when people drop out, we're going to get a lot of votes," he said.
Nevada's caucusing played out in schools, community centers and places of worship across the state - a process that's been chaotic in the past.
Count Tracy Brigida, fed up after her husband was laid off from his mining job, among those caucusing for Trump.
"I want a businessman to run the biggest business in the world," Brigida said as she caucused at a Las Vegas high school.
While Republicans watched the Nevada returns come in, Democrats hit them on the issue of race at CNN's South Carolina town hall meeting.
"This birther issue which we heard from Donald Trump and others, a racist effort to try to delegitimize the president of the United States," Bernie Sanders says.
Bernie Sanders was busy courting the minority vote ahead of the Saturday primary, and hitting rival Hillary Clinton over her paid speeches to Wall Street, demanding she release the transcripts.
Clinton says she would, on one condition.
"Sure, if everybody does it, and that includes the Republicans," Clinton says. "Why is there one standard for me, and not for everybody else?"