The coldest Iowa caucuses in history arrive Monday night amid expectations that Republicans in the state will put former President Donald J. Trump on the march to a third G.O.P. presidential nomination.
The battle for second place, hard-fought between Gov. Ron DeSantis of Florida and Nikki Haley, the former governor of South Carolina, will anoint Mr. Trump’s closest rival ahead of the New Hampshire primary election and beyond.
The stakes for Iowans are high. Mr. Trump is pursuing a return to the presidency despite — or perhaps because of — 91 felony counts from four criminal prosecutions, a looming fraud judgment that could decide the fate of his New York real estate empire and a pending decision on the defamation of a woman he has already been held liable for sexually abusing.
His opponents have implored Republican voters to move past the “chaos” and controversies of the Trump era and pick a different standard-bearer to go up against President Biden, who beat Mr. Trump in 2020. Iowans will render the first verdict on those entreaties.
Here is what to watch as results roll in.
Will Mr. Trump crack 50 percent?
Traditionally, Iowa caucuses are squeakers, so close that Democrats failed to produce definitive results in the chaotic 2020 contest. Republicans falsely declared Mitt Romney the narrow winner in 2012, depriving the actual victor, Rick Santorum, the momentum that a caucus triumph can bring.
This time around, polling has consistently shown Mr. Trump well ahead, so much so that the former president hardly campaigned in the state. Until the final weekend, he and his campaign were projecting confidence in a blowout victory, which has raised expectations when most campaigns seek to lower them.
If Mr. Trump exceeds 50 percent, he will earn what he predicted would be “a historic landslide.” Perhaps more important, Iowa will have signaled that even if the Republican field winnows down to Mr. Trump and one competitor, he still may have the allegiance of a majority of the party’s primary voters, at least in the nation’s heartland.
Who will claim second place?
Mr. DeSantis officially joined the Republican presidential race in May with strong financial backing and talk that he would win Iowa and help the party turn the page on Mr. Trump while still embracing his policies.
But a campaign apparatus built around his super PAC faltered just as Ms. Haley was finding her footing. She had initially focused on New Hampshire and her home state, jumping into Iowa late.
The final Iowa Poll by The Des Moines Register, NBC News and Mediacom, unsurprisingly, had Mr. Trump comfortably in the lead with the backing of 48 percent of likely caucusgoers. Ms. Haley had 20 percent and Mr. DeSantis 16 percent — a separation at the edge of the survey’s margin of error.
A second-place finish for Ms. Haley would give her a boost ahead of New Hampshire, where she has been closing in on Mr. Trump and could benefit from Wednesday’s withdrawal of former Gov. Chris Christie of New Jersey from the presidential contest. For Mr. DeSantis, third place could spell doom ahead of New Hampshire, where he has slipped into single digits in polling averages, and South Carolina, which is a redoubt for Mr. Trump and is Ms. Haley’s home turf.
Can Haley make electability stick?
Ms. Haley’s closing argument in Iowa has been that she would not only defeat Mr. Biden in the general election but would beat him in a resounding landslide that would ring in an era of unified conservative governance in Washington. A CBS News poll released on Sunday showed both Mr. Trump and Mr. DeSantis leading the president narrowly, but Ms. Haley beating him by eight percentage points, 53 percent to 45 percent.
Many Iowa Republicans are confident that Mr. Trump is a proven commodity who can beat Mr. Biden, despite the former president’s personal baggage and legal peril. But Ms. Haley’s electability argument has been persuasive with college-educated Republican voters, 39 percent of whom backed her in a New York Times/Siena College poll released last month.
Her task in Iowa is to make it stick with a significant number of Iowans without a college degree as she tries to appeal to a wider Republican electorate that has been transformed by Mr. Trump into a bastion of voters without a college education. Ms. Haley, in the Times/Siena poll, had the support of just 3 percent of those voters.
Who will show up to caucus?
The Iowa caucuses have never been particularly democratic. The gatherings on Monday at 1,657 sites are more like party meetings. Locals will assemble, conduct some business, hear pitches from representatives of each campaign, and then finally turn in secret ballots. Caucuses can be time-consuming and public — and not particularly well attended.
In 2016, when Republicans held their last contested caucuses, 186,874 votes were cast out of 615,066 registered Republicans, a turnout of about 30 percent.
On Monday night, temperatures will fall to minus 7 degrees in much of the state, where snow is blowing across icy roads. Mr. DeSantis has bragged of a stellar get-out-the-vote operation. Ms. Haley has the door knockers of Americans for Prosperity Action, a conservative activist group funded by the fortune of Charles and David Koch. Mr. Trump has a far more organized ground game than he had in 2016, when he finished second to Senator Ted Cruz of Texas. All of that will be battling the elements.
Mr. Trump told supporters in Indianola, Iowa, on Monday that they should caucus even if “you’re sick as a dog.” Then he joked, “Even if you vote and then pass away, it’s worth it.”
Turnout will not only affect the order of the candidates’ finish but also how real their bragging rights are as they head into the more representative primaries to come.
What about the other candidates?
No one has put as much shoe leather into Iowa as Vivek Ramaswamy, the entrepreneur and increasingly conspiracy-minded political newcomer who briefly saw a spike in support in August, only to dip back into the single digits — 8 percent in the final Iowa Poll.
There’s also former Gov. Asa Hutchinson of Arkansas and a Texas businessman and pastor, Ryan Binkley, both of whom came in with 1 percent in the final Iowa Poll.
Numbers like that don’t indicate that any of them have huge sway, though Mr. Trump was clearly playing for Mr. Ramaswamy’s voters when he attacked his erstwhile ally on Saturday.
Traditionally, the Iowa caucuses have winnowed out the also-rans. Former Vice President Mike Pence, Senator Tim Scott of South Carolina and Gov. Doug Burgum of North Dakota didn’t even make it to the first casting of ballots. (Mr. Burgum endorsed Mr. Trump at the Indianola rally.)
Both Mr. Ramaswamy and Mr. Hutchinson say they will beat expectations.
“I believe I’m the last, best chance this country has,” Mr. Ramaswamy told Iowans at an event on Friday.
But depending on their performance Monday, it remains to be seen whether they will drop out and pick a side: Mr. Trump, or anyone else.
