Get ready for round two: Donald Trump is set to face off with President Joe Biden for the White House once again after winning the New Hampshire primary, promising 10 months of extraordinary tension and bitterness.
The only remaining challenger for the Republican presidential nomination, Nikki Haley, vowed to fight on -- but her defeat on Tuesday left her with no realistic chance of chasing down the 77-year-old former president.
Trump previewed the divisive rhetoric to come in the campaign for November's cliffhanger election with an angry victory speech that attacked Haley for having a "very bad night" and even lashed out at her dress.
Even Biden, 81, accepted it was "now clear" that he faced a rematch with Trump -- one that polling suggests many Americans don't want -- and warned that the future of American democracy itself rode on the result of the election in November.
Haley had hoped for a major upset in the northeastern state, but Trump -- her former boss when she was UN ambassador during his chaotic administration -- won by around 54 percent to 43 percent, with some 91 percent of votes counted.
Having crushed his rivals in the first vote of the campaign in Iowa, Trump said that when the primary contest reaches Haley's home state of South Carolina in February "we're going to win easily."
The twice-indicted former president kept to his hard-right messaging, with no hint of reaching out to the more moderate voters who supported Haley, some of whom were concerned by the 91 criminal indictments facing Trump.
At one point swearing on primetime TV, Trump said the United States was a "failing country" and loaded his speech with ominous warnings about immigration and false claims about winning the 2020 election.
President Biden responded by saying: "It is now clear that Donald Trump will be the Republican nominee."
"And my message to the country is the stakes could not be higher. Our Democracy. Our personal freedoms -- from the right to choose to the right to vote," Biden said in a statement.
His campaign had even started selling merchandise for a rematch, including a t-shirt with the slogan: "Together, we will beat Trump. Again."
Haley insisted the race was "far from over" and told supporters that Democrats actually want to run against right-wing populist Trump due to his record of sowing "chaos."
"They know Trump is the only Republican in the country who Joe Biden can defeat," said Haley, 52, who has recently stepped up attacks on Trump as showing signs of being cognitively impaired.
But no Republican has ever won both opening contests and not ultimately secured the party's nomination.
"I think it's a two-person race now between Trump and Biden," Keith Nahigian, a veteran of six presidential campaigns and former member of Trump's transition team, told AFP.
US media said that the New Hampshire results did hold hope for Biden, despite recent polling showing him neck and neck or even behind Trump in a rematch.
Not only did Trump lose nearly half the Republican vote despite effectively running as an incumbent who is known to voters, but his failure to win over independents and floating voters gave succor to Democrats.
"This was actually a fairly good night for Joe Biden," Trump's former press secretary Kayleigh McEnany told conservative Fox News.
Trump responded by ridiculing McEnany as a "RINO" (Republican in name only) and saying: "Save your advice for Nikki."
New Hampshire was markedly more Haley-friendly than the next states she will face if she stays in.
A once crowded field of 14 Republican candidates narrowed down in recent months before turning into a one-on-one match-up after Florida Governor Ron DeSantis dropped out after Iowa.
"I think it's gonna be a wipeout for Biden. He's gone," said supporter Luis Ferre, 72, who traveled from New York to be at Trump's election night party at a Nashua hotel.
Biden, meanwhile, cruised to victory in an unofficial Democratic primary in New Hampshire, giving him a symbolic boost.
He had not appeared on the ballot after he moved the first primary of the calendar to South Carolina, but the northeastern state went ahead with the vote anyway. However voters "wrote-in" Biden for the win.
Biden is focusing on hot-button issues including abortion and portraying Trump as a threat to democracy, as his economic message fails to resound with inflation-hit voters.
