Donald Trump secured a resounding victory in the first 2024 Republican presidential contest in Iowa on Monday, asserting his command over the party despite facing scores of criminal charges as he seeks a rematch with Democratic President Joe Biden in the US presidential election slated for Nov. 5, 2024.

Florida Governor Ron DeSantis, 45, finished well behind in second place, edging out former UN Ambassador Nikki Haley, 51, as they battle to emerge as the chief alternative to Trump.

Trump, 77, won by an unprecedented margin for an Iowa Republican contest, strengthening his case that his nomination is a foregone conclusion given his massive lead in national polls.

"THANK YOU IOWA, I LOVE YOU ALL!!!" Trump wrote on his social media platform, Truth Social.

With 95 percent of the expected vote tallied, Trump had 51 percent, while DeSantis was at 21 percent and Haley 19 percent, according to Edison Research.

The largest margin of victory for an Iowa Republican caucus had previously been 12.8 percentage points for Bob Dole in 1988.

Entrepreneur Vivek Ramaswamy ended his long-shot presidential bid after earning just under 8 percent of the vote on Monday and endorsed Trump in a speech to supporters.

If Trump finishes above 50 percent, winning more than all his rivals combined, it will further weaken his opponents' argument that his march to the nomination can be derailed.

His performance reflected his popularity among Republican voters -- even after two impeachments, his involvement in the Jan. 6, 2021 attack on the US Capitol by a mob of supporters and his 91 criminal charges for trying to overturn the 2020 election, retaining classified documents after leaving the White House and falsifying records connected to hush money payments to a porn star.

Nearly two-thirds of caucus-goers embraced his false claims about voter fraud, saying they did not think Biden legitimately won the presidency. More than 60 percent said Trump would still be fit to serve as president even if convicted of a crime.

Trump dominated across the board, according to an Edison entrance poll: he won a majority among men and among women; among those who consider themselves very conservative, somewhat conservative and independent; among those who graduated college and those who did not.

He captured a majority of Republicans who put immigration as their top concern -- and a majority of those who said the economy was their main worry.

"The Iowa caucus results demonstrate the strength of Trump’s grip on the Republican Party," said Jimmy Centers, an Iowa-based Republican strategist. "Absent a quick consolidation of the field, Trump appears to be on a fast track to the nomination."

That consolidation appears unlikely, with both DeSantis and Haley vowing to press ahead following Monday's results, ensuring Trump's opposition will remain fractured as the campaign moves to other states.

DeSantis in particular had wagered his campaign on Iowa, barnstorming all of its 99 counties and pouring resources into the state.

"We've got our ticket punched out of Iowa!" DeSantis told supporters in West Des Moines on Monday.

Haley, who has enjoyed a steady rise in polls over the last few months, sought to position herself as the leading Trump challenger.

"At one point in this campaign there were 14 of us running. I was at 2 percent in the polls," Haley told a crowd of supporters.

"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 said.

Republicans in more moderate New Hampshire will choose their nominee eight days from now. Polls show Trump with a smaller lead over Haley there, with DeSantis far behind.

Trump has aimed to create an air of inevitability around his campaign, skipping all five of the Republican debates thus far and largely eschewing the county-by-county politicking that most candidates do ahead of the Iowa vote. (Reuters)