Florida Governor Ron DeSantis ended his Republican presidential campaign on Sunday and endorsed Donald Trump.
Mr DeSantis announced his decision in a video posted on X.
He said he was endorsing Mr Trump because “we can't go back to the old Republican guard of yesteryear”, and criticised former UN ambassador Nikki Haley, the only remaining Republican challenger to the former president.
Mr DeSantis's withdrawal from the race comes just two days before the New Hampshire primary, where Ms Haley is trailing Mr Trump.
Mr DeSantis, 45, had been widely seen as a top contender for the 2024 Republican nomination and a natural heir to Mr Trump due to his combative style and deeply conservative views.
Early in 2023, he led several head-to-head polls against Mr Trump.
But Mr DeSantis's support has been declining for months, due to a flawed campaign strategy, his seeming lack of ease with voters on the campaign trail and Mr Trump's so far unshakeable hold on much of the party's base.
He lost the Iowa caucuses to Mr Trump by a wide margin and got embroiled in a series of superficial distractions, including being mocked for supposedly wearing heel lifts inside his cowboy boots to appear taller.
Mr DeSantis’s political future is in question after suspending his bid following only one voting contest.
He can only serve one term as Florida Governor.
