Trump has a 28 point lead and Nikki Haley overtakes Ron

Trump has a 28-point lead and Nikki Haley overtakes Ron DeSantis for second place in the final Iowa caucus vote: Vivek Ramaswamy comes fourth as the former president holds a commanding lead

Donald Trump is on his way to a big victory in the Iowa caucuses. This is according to the last poll before the decision day, which predicts that he will receive 48 percent of the vote.

However, NBC News/Des Moines Register/Mediacom Iowa shows that it is Nikki Haley who continues her rise, narrowing Trump's lead and giving her a clear second place at 20 percent.

That puts Florida Gov. Ron DeSantis in third place with 16 percent, in a state where he needs a strong second place finish to keep his campaign on track.

The state is the first in the country to select its preferred candidate and can make or break election campaigns.

On Saturday evening, Ann Selzer, the state's best-known and most accurate pollster, released her highly anticipated final poll before caucus day.

Donald Trump has crushed his opponents in the polls in Iowa.  But things get serious on Monday night at 7 p.m. when Republicans come together to choose their favorite candidate.  The last survey before the parliamentary group meeting gave him an approval rating of 48 percent - three points less than in the same survey in December

Donald Trump has crushed his opponents in the polls in Iowa. But things get serious on Monday night at 7 p.m. when Republicans come together to choose their favorite candidate. The last survey before the parliamentary group meeting gave him an approval rating of 48 percent – three points less than in the same survey in December

Former South Carolina Governor Nikki Haley Florida Governor Ron DeSantis

Nikki Haley and Ron DeSantis are fighting for second place in Iowa

In their December poll, Trump got 51 percent, DeSantis got 19 percent and Haley got 16 percent.

That means the former president has faded slightly, while it's Haley, the former governor of South Carolina, who has the momentum as the candidates get down to business in the race.

“This is a tough poll for Gov. DeSantis, who has bet on Iowa,” said Jimmy Centers, a Republican strategist who is nonpartisan in the race.

“The good news is that many Iowans are leaving the door open to changing their minds or have not decided on a candidate yet.”

“But voters generally like to side with a winner or an up-and-coming candidate – he doesn’t appear to be either.”

In other parts of the poll, Haley fared less well, with only nine percent of her supporters saying they were “extremely enthusiastic” about her.

“There is a fundamental weakness here,” said Selzer, who conducted the survey. “If turnout is low, it seems to me that a disproportionate number of their supporters might stay home.”

Rebellious tech entrepreneur Vivek Ramaswamy comes in fourth place with eight percent.

Trump lost Iowa in 2016 to Ted Cruz, who was better able to court the state's large evangelical electorate.

Republican presidential candidate and businessman Vivek Ramaswamy is at eight percent

Republican presidential candidate and businessman Vivek Ramaswamy is at eight percent

This time, Trump's campaign team left nothing to chance, setting up a big field game to get out the vote on Monday and hitting his rivals hard.

However, a number of polls showing him 30 points ahead of his nearest rivals mean anything less than a record win will be seen as a bad result, encouraging DeSantis and Haley to move on.

DeSantis, for his part, has squandered much of his campaign resources on Iowa. He knows that New Hampshire, the next state to make his decision, is less fertile ground for his conservative, anti-woke message.

In contrast, Haley is doing well in the Granite State and can afford a modest finish in Iowa.

They returned to campaign rallies on Saturday, battling freezing weather to appeal to Republicans, who have 48 hours to decide.

Haley appeared in the college town of Iowa City, one of the most Democratic areas in the state. It is consistent with their efforts to win over independents and moderates.

Both challengers ended the day with events in the Mississippi city of Davenport, one of the more Republican cities in the eastern part of the state.

In contrast, Trump abandoned plans for two rallies and called for “tele-rallies” instead.

DeSantis mocked his strategy.

“We’re there, we’re coming over.” Donald Trump called. He'll be at Mar-a-Lago. It's probably 75 degrees there,” he told supporters in Council Bluffs, where the outside temperature was -5 degrees Celsius.

The bitter weather could bring another twist to a notoriously difficult to predict system.

Campaigns will have to work even harder to ensure they get their supporters to Monday's caucuses.