DES MOINES, Iowa >> Donald Trump won the Iowa caucuses Monday, a crucial victory at the outset of the Republican primary that reinforces the former president’s bond with his party’s voters even as he faces extraordinary legal challenges that could complicate his bid to return to the White House.

The magnitude of Trump’s success is still coming into focus, but the former president’s supporters endured a historic and life-threatening cold snap to participate in caucus meetings that unfolded in schools, churches and community centers across the state.

The results are just the first in what will be a monthslong effort for Trump to secure the GOP nomination a third consecutive time. But they send an unmistakable message to the Republican Party that the nomination is Trump’s to lose and crystallize the challenge facing his GOP opponents.

Former U.N. Ambassador Nikki Haley and Florida Gov. Ron DeSantis are Trump’s most prominent primary rivals. They are aiming for a second-place finish in Iowa that would give them at least some momentum heading into future races. Both are already pivoting their focus, with Haley poised to compete vigorously in New Hampshire, where she hopes to be more successful with the state’s independent voters heading into the Jan. 23 primary. DeSantis, meanwhile, is heading straight to South Carolina, a conservative stronghold where the Feb. 24 contest could prove pivotal, before then going to New Hampshire.

The opening contest in the monthslong Republican primary process unfolded inside more than 750 schools, churches and community centers where participants gathered to debate their options before casting secret ballots.

Entrepreneur Vivek Ramaswamy and former Arkansas Gov. Asa Hutchinson are also on the ballot in Iowa, as is former New Jersey Gov. Chris Christie, who suspended his campaign last week.

With the coldest temperatures in caucus history and dangerous travel conditions in virtually every corner of the state, the campaigns were bracing for a low-turnout contest that will test the strength of their support and their organizational muscle. The final result will serve as a powerful signal for the rest of the nomination fight to determine who will face Democratic President Joe Biden in the November general election.

After Iowa, the Republican primary shifts to New Hampshire, Nevada and South Carolina over the coming weeks before moving into the rest of the country this spring. The ultimate nominee won’t be confirmed until the party’s national convention in July, but with big wins in the opening contests, Trump will be difficult to stop.

Trump’s political strength heading into the Iowa caucuses, which come 426 days after he launched his 2024 campaign, tells a remarkable story of a Republican Party unwilling or unable to move on from him. He lost to Biden in 2020 after fueling near-constant chaos while in the White House, culminating with his supporters carrying out a deadly attack on the U.S. Capitol. In total, he faces 91 felony charges across four criminal cases, including two indictments for his efforts to overturn the election and a third indictment for keeping classified documents in his Florida home.

In recent weeks, Trump has increasingly echoed authoritarian leaders and framed his campaign as one of retribution. He has spoken openly about using the power of government to pursue his political enemies. He has repeatedly harnessed rhetoric once used by Adolf Hitler to argue that immigrants entering the U.S. illegally are “poisoning the blood of our country.” And he recently shared a word cloud last week to his social media account highlighting “revenge,” “power” and “dictatorship.”

Trump’s top surrogates played up the stakes Monday.

“I truly believe that God has placed each and every one of us here at this moment, for this moment to save this country,” Arizona Senate candidate Kari Lake told Trump supporters in Fort Dodge.

The final Des Moines Register/NBC News poll before the caucuses found Trump maintaining a formidable lead, supported by nearly half of likely caucusgoers, compared with 20% for Haley and 16% for DeSantis, who are in a close battle for second. Trump is also viewed more favorably than the other top contenders by likely caucusgoers, at 69% compared with 58% for DeSantis and 48% for Haley.

More than 1,000 miles to the east, Biden’s campaign sought to signal strength from its Delaware headquarters.

The Democratic president’s team announced early Monday that he and the Democratic National Committee raised more than $97 million in the last quarter of 2023 and finished the year with $117 million in the bank. His team wants to offer a stark contrast between the two parties: While Biden is flush with cash entering 2024, facing token opposition in the Democratic primary, the Republican field has spent more than $90 million on Iowa advertising alone, much of it designed to attack each other.

Meanwhile, Trump used his Truth Social site early Monday to knock Haley. Her campaign answered that Trump’s diatribes, some of them contradictory, prove he considers her a threat.

Haley began the day in central Iowa by encouraging some of her caucus precinct captains to “speak from the heart” as they make their statements on her behalf before votes are cast.

Trump predicted he would set a modern-day Republican caucus record with a margin-of-victory exceeding the nearly 13-percentage-point victory that Bob Dole earned in 1988. Still, he played down expectations that he would eclipse 50%, preempting any criticism that a majority of Republican voters might prefer someone else.

The winter weather, intimidating even for Iowa with a forecast of minus 14 degrees Fahrenheit and “dangerously cold wind chills, were expected to make an already unrepresentative process even less representative. Only a tiny portion of the participants will be voters of color, given Iowa’s overwhelmingly white population, a fact that helped persuade Democrats to shift their opening primary contest to South Carolina this year.

Iowa’s caucuses also played out on Martin Luther King Day, a federal holiday.