Former President Donald Trump cruised to an easy victory on Monday night in the Iowa caucuses, the lead off contest in the 2024 Republican presidential nominating calendar.

The Fox News Decision Desk made call for Trump at 8:31pm ET, a half an hour after the caucuses got underway across the Hawkeye State.

The former president's lightning-fast win in Iowa gives him a crucial early victory in his bid to return to the White House.

"We want to thank the great people of Iowa," Trump said in a caucus victory speech in Des Moines, the state's capital and largest city.

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Donald Trump quickly wins the Iowa caucuses

Republican presidential candidate former President Donald Trump arrives to speak at a caucus night party in Des Moines, Iowa, Monday, Jan. 15, 2024. (AP Photo/Andrew Harnik) (AP Photo/Andrew Harnik)

More than two hours after Trump's victory was called, the Fox News Decision Desk projected that Florida Gov. Ron DeSantis would edge former ambassador to the United Nations and former South Carolina Gov. Nikki Haley for a distant second place behind Trump.

"They threw everything but the kitchen sink at us," DeSantis said in a speech to supporters, as he referenced the onslaught of negative attacks and ads he faced from his rivals.

"Because of your support, in spite of all of that that they threw at us, everyone against us, we've got our ticket punched out of Iowa," he touted.

Ron DeSantis comes in second in Iowa caucuses

Republican presidential candidate Florida Gov. Ron DeSantis speaks to supporters during a caucus night party, Monday, Jan. 15, 2024, in West Des Moines, Iowa. (AP Photo/Charlie Neibergall) (AP Photo/Charlie Neibergall)

Haley, addressing her supporters soon after DeSantis spoke, one again framed the nomination race as a two-person contest between herself and Trump.

"When you look at how we're doing in New Hampshire, in South Carolina, and beyond, I can safely say tonight Iowa made this Republican primary a two person race," she argued.

Nikki Haley comes in third in Iowa

Republican presidential candidate former UN Ambassador Nikki Haley speaks at a caucus night party at the Marriott Hotel in West Des Moines, Iowa, Monday, Jan. 15, 2024. (AP Photo/Abbie Parr) (AP Photo/Abbie Parr)

Multimillionaire biotech entrepreneur and first time candidate Vivek Ramaswamy, who relentlessly campaigned across Iowa in recent months, suspended his campaign after finishing a distant fourth place.

Ramaswamy said he called Trump to congratulate him and said he would attend a rally with the former president in New Hampshire on Tuesday.

"There needs to be an America First candidate in this race," Ramaswamy said. "Going forward, he will have my full endorsement for the presidency."

Vivek Ramaswamy suspends his presidential campaign

Republican presidential candidate businessman Vivek Ramaswamy speaks at a caucus site at Horizon Events Center, in Clive, Iowa, Monday, Jan. 15, 2024. (AP Photo/Andrew Harnik) (AP Photo/Andrew Harnik)

Trump, speaking with Fox News Digital's Brooke Singman after his victory was projected, said he was "greatly honored by such an early call."

"It really is an honor that, minutes after, they’ve announced I’ve won—against very credible competition — great competition, actually," Trump said.

Trump campaign senior adviser Chris LaCivita posted to social media a photo of the former president backstage at his Iowa campaign caucus night headquarters, along with his son, Donald Trump Jr., giving the thumbs up sign in front of a TV tuned to Fox News, with the chyron "TRUMP PROJECTED TO WIN IOWA CAUCUS."

Trump made history last year as the first former or current president to be indicted for a crime, but his four indictments, including charges he tried to overturn his 2020 presidential election loss, have only fueled his support among Republican voters.

And heading into Monday's caucuses, Trump enjoyed a massive lead in public opinion polls in Iowa and in national surveys in the GOP nomination race.

Trump's victory on Monday night was the largest margin in the history of Iowa's Republican presidential caucuses, easily surpassing the previous winning margin of 12.8 percent set in 1988 by the late Sen. Bob Dole.

And with nearly all of the ballots counted by late Monday, Trump stood at 51%, to capture a majority of the vote in the caucuses. Rival campaigns and many political pundits had argued that if Trump failed to top 50% of the vote, he wouldn't meet expectations. 

Donald Trump fights against expectations in Iowa

Republican presidential candidate former President Donald Trump speaks at a rally at Simpson College in Indianola, Iowa, Sunday, Jan. 14, 2024. (AP Photo/Andrew Harnik) (AP Photo/Andrew Harnik)

Trump, who narrowly lost the 2016 Iowa caucuses to Sen. Ted Cruz of Texas, assembled a formidable get-out-the-vote machine in the state over the past year.

LaCivita emphasized that the campaign put an emphasis on volunteer support.

"They know the area and they know who’s caucusing in their area and they’ll be following up with them, making sure they vote," he told Fox News this past weekend. "Our focus and our premium has been on people.. and we think it’s going to bear fruit in a big way."

Veteran Iowa-based Republican strategist Jimmy Centers told Fox News that Trump "won across all demographics. You look at northwest Iowa – the most conservative part of the state. Evangelical voters. He won. You look at suburban population centers. He won. You look at the rural counties that he spent the last few weeks visiting. He won and he won big in those counties."

"It tells me they had a very sophisticated data-driven operation. They knew where their margins were. They hit those in the final stretch to get that number up over 50%. It’s a really impressive showing," added Centers, a veteran of multiple presidential campaigns, gubernatorial and congressional campaigns, and who served as communications director for then-Iowa Gov. Terry Branstad and current Gov. Kim Reynolds.

DeSantis stands in third place in the latest polls ahead of the Iowa caucuses

Republican presidential candidate Florida Gov. Ron DeSantis, right, takes the microphone after being introduced at an event in West Des Moines, Iowa, Saturday, Jan. 13, 2024. Also on stage with him are Iowa Gov. Kim Reynolds, left, and DeSantis wife, Casey DeSantis. (AP Photo/Pablo Martinez Monsivais) (AP Photo/Pablo Martinez Monsivai)

DeSantis, who was convincingly re-elected to a second term as Florida governor 14 months ago, was once the clear alternative to Trump in the Republican White House race. 

However, after a series of campaign setbacks over the summer and autumn, and after getting hammered by negative ads, DeSantis saw his support in the polls erode.

Heading into the caucuses, DeSantis was betting that his vaulted ground game in Iowa, which is heavily reliant on the aligned super PAC Never Back Down, would carry him across the finish line.

DeSantis, who made Iowa the major focus of his White House bid, predicted on "Fox News Sunday" that "we're going to do well on Monday. We've got an unbelievable organization."

The AP and numerous news networks projected Trump's victory as people were still casting ballots at many caucus sites across Iowa.

The DeSantis campaign blasted the move, with spokesman Andrew Romeo charging that the early call was "absolutely outrageous" and claiming that "the media is in the tank for Trump and this is the most egregious example yet."

Nikki Haley campaigns in Iowa hours aheead of the caucuses

GOP presidential hopeful Nikki Haley speaks to supporters gathered for one of her final stops ahead of Iowa's Republican caucus on Monday, Jan. 15, 2024, in Newton, Iowa. (AP Photo/Meg Kinnard) (AP Photo/Meg Kinnard)

Haley, who finished narrowly behind DeSantis, grabbed momentum during the autumn and caught up with DeSantis for second place in polls in Iowa and in national surveys in recent weeks. 

She also surpassed DeSantis and surged to second place and narrowed the gap with Trump in New Hampshire, the state that holds the first primary and second overall contest in the GOP nominating calendar, eight days after Iowa's caucuses.

Trump, who has repeatedly blasted his rivals for months, appeared conciliatory in his victory speech.

"I want to thank Ron and Nikki for having a good time together. We’re all having a good time together. I think they both actually did very well," Trump said.

And he said that Ramaswamy "did a hell of a job."

Pointing to all three rivals, Trump added "they’re very smart people, very capable people."

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.