US presidential contender Ron DeSantis, once viewed as Republicans’ best shot at moving past Donald Trump, has dropped out of the primary race.

“It’s clear to me that a majority of Republican primary voters want to give Donald Trump another chance,” the Florida governor said in a video posted on X late on Sunday (US time).

It came just two days ahead of New Hampshire’s first-in-the-nation primary on Tuesday.

DeSantis’ decision, while not surprising given his 30-point blowout loss last week in Iowa, marks the end of an extraordinary decline for a high-profile governor once thought to be a legitimate threat to Trump’s supremacy in the Republican Party.

He entered the 2024 presidential contest with major advantages in his quest to take on Trump, and early primary polls suggested DeSantis was in a strong position to do just that.

“Success is not final, failure is not fatal: It is the courage to continue that counts,” he captioned his tweet announcing he was quitting the race – claiming it was a quote from Winston Churchill.

However, it appears that Churchill never said it.

DeSantis and his allies amassed a political fortune well in excess of $US100 million ($152 million), and he boasted a significant legislative record on issues important to many conservatives, such as abortion and the teaching of race and gender issues in schools.

But such advantages did not survive the reality of US presidential politics in 2024.

From a high-profile announcement that was plagued by technical glitches to constant upheavals to his staff and campaign strategy, DeSantis struggled to find his footing in the primary.

He lost the Iowa caucuses – which he had vowed to win – by 30 percentage points to Trump.

On Sunday, as he suspended his campaign for the presidential nomination, he endorsed Trump.

“It’s clear to me that a majority of Republican primary voters want to give Donald Trump another chance,” DeSantis said.

“While I have had disagreements with Donald Trump such as on the coronavirus pandemic and his elevation of Anthony Fauci, Trump is superior to the current incumbent Joe Biden. That is clear.”

The endorsement was a stunning tail-between-his-legs moment for DeSantis, whom Trump has mercilessly and relentlessly taunted in deeply personal terms for the better part of a year.

Trump and his aides have blasted the governor as disloyal for running in the first place, mocked his eating habits and his personality and accused him of wearing high heels to boost his height.

Trump addressed DeSantis’ departure shortly after it was announced during a stop at Manchester campaign headquarters, according to a video shared by his staff.

“We just got some word that one of our opponents, very capable person, is dropping out of the race – Ron DeSantis. And Ron is dropping out and, in doing so, he endorsed us,” Trump said to cheers, before a “Trump!” chant broke out in the room of volunteers.

Asked if he would keep using the name “Ron DeSanctimonious”, Trump said to loud cheers: “I said that name is officially retired.”

On his way out, DeSantis also took a swipe at former US ambassador to the UN, Nikki Haley, who is now the key rival to Trump for the Republican presidential nomination.

“I signed a pledge to support the Republican nominee and I will honour that pledge. He has my endorsement because we can’t go back to the old Republican guard of yesteryear – a repackaged form of warmed-over corporatism that Nikki Haley represents,” DeSantis said.

Haley was campaigning in Seabrook, New Hampshire, on Sunday when DeSantis announced his decision.

“He ran a great race, he’s been a good governor, and we wish him well,” she told a room packed with supporters and media.

“Having said that, it’s now one fella and one lady left.”

His own political future is now in question after suspending his presidential bid after just one voting contest. The 45-year-old is term limited as Florida governor.

-with AAP