Trump fends off Haley with double-digit win and other takeaways from New Hampshire's primary

Former President Donald Trump is projected to score a double-digit victory in New Hampshire's primary on Tuesday, marking a second and crucial step toward securing the 2024 Republican nomination.

With more than 73% of the estimated vote in as of late Tuesday, Trump was in first with 54% and former South Carolina Gov. Nikki Haley was in second with 44%.

Though Haley played up that second-place finish in a speech after polls closed -- drawing Trump's scorn -- she had staked much of her campaign on winning over New Hampshire voters given the state's more anti-Trump electorate and its rules allowing independents to participate in the primary.

Polls show she is much further behind Trump than 10 points in various other parts of the country, including South Carolina, where they will next face off next month.

On the Democratic side, a write-in campaign for President Joe Biden handily won his race, which was unsanctioned by the Democratic National Convention after New Hampshire refused to move the race's date to jive with the DNC's calendar of having South Carolina hold the nation's first primary.

Here are three takeaways from Tuesday night's results.

Trump margin expected to stay in double digits

Experts have long said that New Hampshire had the makings of the kind of state that could blunt Trump's momentum and help boost one of his primary rivals.

Among other things, the state boasts an electorate more moderate than that of Iowa, where Trump romped in the caucuses last week. And by Tuesday, only one major opponent remained, Haley, which could have allowed anti-Trump voters to coalesce around her.

In the end, though, Trump again emerged victorious, dashing Haley's hopes of a narrow win or a truly close second-place finish and cementing even further his popularity in the GOP.

The next two contests are set to be held on significantly more friendly terrain for Trump.

He'll enter Nevada's caucuses in early February with a huge lead with voters there, per polling, and Haley isn't even competing in them. South Carolina will hold its primary on Feb. 24 -- and even though it's Haley's home state, Trump currently leads by about 36 points in 538's polling average.

Trump's allies flexed after the former president's strong showing, pointing to the results as evidence that the primary was never competitive in the first place.

"After President Trump's resounding victory in New Hampshire tonight people will say this primary is over. The truth is, tonight's result proves it never existed at all. President Trump has been our nominee all along. It's now time for the entire Republican Party to unite behind our nominee to defeat Joe Biden in November," Kari Lake, the Arizona GOP Senate candidate rumored to also be a possible vice-presidential pick for Trump, said in a statement.

"It's time for unity, it's time to take the fight to the Democrats, and for Nikki Haley: it's time to drop out," added Taylor Budowich, who heads the main pro-Trump super PAC.

Biden's campaign didn't disagree with that assessment of the race.

"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," he said in a statement.

Haley stays in, for now

Haley on Tuesday night played down any possibility she'd be exiting the race.

Her team had steadily lowered expectations in New Hampshire from projecting a victory to saying they would settle for a respectable second place and hope for a better result in South Carolina next month.

In a speech to supporters, Haley indicated she plans on staying in the race through South Carolina's primary and Super Tuesday on March 5, where the lion's share of delegates is up for grabs.

"In the next two months, millions of voters in over 20 states will have their say. We should honor them and allow them to vote. And guess what? In the next two months, Joe Biden isn't going to get any younger or any better. We'll have all the time we need to defeat Joe Biden. When we get to South Carolina, Donald Trump's going to have a harder time … attacking me," she said.

"South Carolina voters don't want a coronation. They want an election. And we're going to give them one," she said. "Because we are just getting started."

Haley also took pointed swipes at Trump, indicating an escalation of their back-and-forth that Haley had appeared reticent to engage in early in the campaign.

"[Democrats] know Donald Trump is the only Republican in the country who Joe Biden can beat," Haley said. "You can't fix the mess if you can't win the election. A Trump nomination is a Biden win and a Kamala Harris presidency."

She also noted Trump's reluctance to debate her and a recent gaffe when he confused her with former House Speaker Nancy Pelosi -- while also reiterating her call for mental competency tests for elderly politicians.

Trump is 77, and Biden is 81.

"Most Americans do not want a rematch between Biden and Trump. The first party to retire its 80-year-old candidate is going to be the party that wins this election. And I think it should be the Republicans that win this election. So, our fight is not over because we have a country to save," she said.

Biden write-in campaign handily defeats Phillips, Williamson

The write-in campaign set up by Biden allies is projected to have easily dispatched Democratic challengers Rep. Dean Phillips and author Marianne Williamson.

While the Democratic primary will not award any delegates after being disavowed by the DNC, party leaders were concerned that a victory or near-second by either of the two challengers would mark a major embarrassment for the president, just as Democrats try to quell hand-wringing over Biden's age, handling of the economy and poor standing in early polls of the 2024 race.

In the end, though, Biden was at 67% with write-ins while Phillips hovered around 20% and Williamson failed to break 5% as of late Tuesday, with more than 41% of the vote counted. (Williamson's campaign manager, Carlos Cardona, soon quit but told ABC News that there was no bad blood and the campaign planned to keep going.)

Still, Phillips reiterated in a speech on Tuesday that he has concerns about a Biden-Trump rematch and said he will stay in the race, despite failing to beat a man who didn't compete in New Hampshire or even appear on the ballot.

"Joe Biden is a good man. He's a fine man. Yes, he is everybody, he's our president, but I gotta tell you, everyone, he cannot win. The polls are saying he cannot win, his approval numbers are saying you can't win, and the fact that an unknown congressman from Minnesota two weeks before the election said I'm going to come out here and run for president just got 21%, that says something," Phillips said.

"We're going to go to South Carolina, and then we are going to go to Michigan, and then we are going to go to all the Super Tuesday states," he added.

ABC News' Isabella Murray and Brittany Shepherd contributed to this report.