Trump ahead as Iowa vote kicks off 2024 race

A highly anticipated poll set the tone for a final full day of campaigning in ice-cold Iowa on Sunday, with Donald Trump maintaining a big lead and Nikki Haley overtaking Ron DeSantis for second place in the Republican presidential race.

The Des Moines Register/NBC News poll released late on Saturday gave Trump 48 per cent, though his lead slipped by 3 percentage points from the December poll. Former South Carolina Governor Haley was second at 20 per cent, up 4 points, followed by Florida Governor DeSantis with 16 per cent, down 3 points.

Organisers of the poll pride themselves on taking an accurate snapshot of the mood of Iowa voters.

The survey provided a strong indication that Trump was poised to do well in Monday's caucuses, the first voting contest on the road to the presidential election in November.

A victory would give Trump, 77, an important big step toward securing the Republican nomination to face the Democratic incumbent, Joe Biden, 81, in a rematch of their 2020 battle. It would be evidence that many Republicans are willing to look past Trump's mounting legal problems and inflammatory rhetoric.

Trump plans a Sunday rally in Indianola, a suburb of the capital Des Moines, but the weather forced him to cancel one in the city of Cherokee. The former president cancelled two events on Saturday, appearing in the evening on a campaign livestream.

"We are leading by a lot in all the polls and you have to get out," Trump told his supporters. "We need to send a message most importantly for November."

DeSantis and Haley, who was Trump's UN ambassador, both need to do well enough in Iowa to give them some momentum for the next contest, in New Hampshire on January 23.

The DeSantis campaign predicted a strong performance on Monday night, despite the slip in the widely watched poll.

"Winning campaigns don’t rely on public data. Most importantly, no one has worked harder and is better organized than Ron DeSantis," spokesman Andrew Romeo said.

Their battle increasingly bitter, Haley and DeSantis begin Sunday in Dubuque in the east of the state near the Mississippi River, followed by another DeSantis event around 500 km away in Sioux City.

From 7:00 pm CST on Monday (0100 GMT on Tuesday), Iowans will gather for two hours in school gymnasiums, bars and other locations to debate the Republican candidates before ranking them in order of preference.

Results are typically announced within a few hours.

With temperatures plunging, one question facing the candidates was whether their supporters would be sufficiently motivated to brave the cold and show up to caucus.

Forecasters predict the coldest Iowa caucus night ever - minus 30 degrees Celsius.

DeSantis, speaking at an event in West Des Moines on Saturday, urged people to make the effort.

“It’s not going to be pleasant,” he said. “But if you’re willing to go out there and you’re willing to fight for me... then as president I’ll be fighting for you for the next eight years.”