Former President Trump is expanding his already formidable lead in the state that leads off the Republican presidential nominating calendar, according to a new and highly reputable poll.

The former president stands at 51% support among those likely to take part in Iowa’s Republican presidential caucuses, with Florida Gov. Ron DeSantis a distant second at 19%, and former ambassador to the United Nations and former South Carolina Gov. Nikki Haley at 16%, according to the latest NBC News/Des Moines Register/Mediacom poll.

The survey, conducted Dec. 2-7, was released on Monday, with five weeks to go until the Jan. 15 Iowa caucuses.

Trump’s lead over the rest of the field of 2024 GOP nomination rivals – which has expanded by five points since October – is the largest recorded so close to a competitive Republican caucus in the history of the survey, which is considered by many to be the gold standard of Iowa caucus polling.

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J. Ann Selzer, the pollster who has conducted the survey for the past three decades, pointed to the recent winnowing of the once large Republican presidential field and noted that “the field may have shrunk, but it may have made Donald Trump even stronger. I would call his lead commanding at this point.”

Trump is aiming for a big victory next month in the caucuses to try and bring the nomination race to an early conclusion, so he can focus on a rematch with President Biden, who defeated him in the 2020 election.

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Trump’s large double-digit lead in the survey is fueled in part by strong support of evangelical voters – who enjoy outsized influence in Iowa Republican politics – and likely first-time caucus goers. Additionally, nearly three-quarters of Iowa Republicans who believe Trump can defeat Biden in next year’s general election – despite the former president’s numerous legal challenges – back Trump.

Trump made history earlier this year as the first former or current president to be indicted for a crime, but his four indictments – including in federal court in Washington, D.C., and in Fulton County court in Georgia on charges he tried to overturn his 2020 presidential election loss – have only fueled his support among Republican voters.

The new poll in Iowa is also the latest to suggest that Trump supporters are more enthusiastic and committed to support their candidate than those backing the former president’s GOP rivals.

As Fox News first reported last week, the Trump campaign said it was shifting into a higher gear in the final weeks leading up to the Iowa caucuses.

“We have an extremely aggressive operation and an extremely aggressive schedule,” Trump campaign senior adviser Chris LaCivita told Fox News Digital.

LaCivita previewed that the Trump campaign is planning a slew of Iowa visits not only from the former president, but also from “dozens of surrogates that are going to be storming the state campaigning… in every venue that has people.”

He said there were “close to 1,500-1,600 precinct captains throughout the state that, literally, their sole job is to run each individual caucus that takes place and making sure that the list of the targeted voters supporting President Trump show up.”

Trump’s campaign said it was not taking anything for granted. Looking ahead to the final stretch leading up to the caucuses, LaCivita said “our only concern is complacency.”

DeSantis, meanwhile, earlier this month fulfilled his goal of stopping in all of Iowa’s 99 counties. He has repeatedly been joined on the campaign trail in the Hawkeye State by popular Iowa Republican Gov. Kim Reynolds, who endorsed him in early November.

Also backing DeSantis was Bob Vander Plaats, president and CEO of The Family Leader, an influential social conservative organization in the state.

DeSantis has repeatedly vowed he will pull off an upset by winning Iowa.

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Haley, who has enjoyed momentum in the polls in recent months, thanks in part to well-received performances in the first three GOP presidential primary debates, has leapfrogged DeSantis for second place in New Hampshire, which holds the first primary and votes second in the Republican nominating schedule, and her home state, which holds the first southern contest.

She also aims to make a fight of it in Iowa, where the new poll is the latest to suggest she is close to pulling even with DeSantis for second place.

Two weeks ago, Haley landed the backing of Americans for Prosperity Action, the political wing of the influential and deep-pocketed fiscally conservative network founded by the billionaire Koch Brothers. AFP Action has pledged to spend tens of millions of dollars and mobilize its formidable grassroots operation to boost Haley and help push the Republican Party past Trump.

The new NBC News/Des Moines Register/Mediacom survey indicates multimillionaire biotech entrepreneur and first time candidate Vivek Ramaswamy at 5% support in Iowa. Ramaswamy, who has spent millions of his own money on his campaign, has predicted that he will pull off a “surprise” in Iowa, where he has spent plenty of time reaching out to voters.

Former New Jersey Gov. Chris Christie, who is making his second bid for the White House, stands at 4% support in the poll. However, Christie has not campaigned in the Hawkeye State, as he concentrates most of his time and resources in New Hampshire.

The poll also indicates former Arkansas Gov. Asa Hutchinson at 1%. Hutchinson remains in the 2024 race even after failing to make the stage at the past three Republican presidential nomination debates.

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.