Even as he trails Trump by close to 30 percentage points in national polls, DeSantis and his advisers are sticking to a long-haul, Iowa-first strategy. They hope that an upset win in the state would stall Trump's momentum, according to two sources close to the campaign, who asked not to be identified so that they could discuss campaign strategy.

They acknowledged they might never fully close the national polling gap before Iowa's caucuses on Jan. 15, the first in a series of nominating contests to decide the Republican nominee for the November 2024 presidential election.

The focus on Iowa appears to be a recognition by the campaign that DeSantis' other paths to victory are shrinking, turning the Midwestern state into a do-or-die for him, according to more than a dozen interviews with the DeSantis campaign, Trump advisers, grassroots Republican operatives in Iowa and donors.

After a much-anticipated presidential launch on May 24, DeSantis is languishing a distant second in the Republican field and has yet to catch fire in any real way.

"A win in Iowa, a second in New Hampshire, we lose a couple candidates before Nevada and South Carolina, and then we are in a bloody, two-person race," one of the two sources told Reuters, referring to other nominating contests that will follow.

But even winning Iowa, should DeSantis pull it off, carries risk. His play for the state's religious voters by staking out hardline positions on abortion and transgender issues could alienate voters in states further down the nominating calendar.

"He's gotta have a win in the first three primaries, and Iowa is his best bet," said Chris Stirewalt, an elections analyst with the American Enterprise Institute, a conservative think tank.

Stirewalt said the biggest fear of the donors he has spoken to is that DeSantis wins Iowa but becomes a candidate "with the resources to stick around but not the reach to win the nomination."

None of the last three winners of a competitive contest in Iowa - U.S. Senator Ted Cruz, former U.S. Senator Rick Santorum and former Arkansas Governor Mike Huckabee - went on to claim their party's nomination, in part because of their conservative stances.

Embarrassingly for DeSantis, Steve Cortes, a spokesperson for Never Back Down, a fundraising super PAC supporting him, acknowledged earlier this month in a Twitter forum that "clearly Donald Trump is the runaway front-runner."

Amid a flurry of stories questioning his viability over the past week, DeSantis has accused the media of prematurely writing his obituary.

"They've tried to create a narrative that somehow the race is over," he said on the Fox Business channel on Monday.

DeSantis' campaign has argued that his ability to raise $20 million in the first six weeks of his campaign shows that donors view him as the top alterative to Trump. In the second quarter, Trump raised $35 million, according to a campaign official.

KNOCKING ON DOORS

Of the 640,000 doors that Never Back Down has knocked on so far nationally, a full quarter have been in Iowa, according to a person connected with the group with knowledge of internal metrics.

The group expects to have opened five offices across the state by the end of July, a separate person said, an unusually large number at this point in the campaign, according to people with knowledge the operations of outside spending groups.

"I think the DeSantis people have done themselves a huge favor by getting a door-to-door operation going early," said Ryan Frederick, chair of the Republican Party in Adair County in rural western Iowa. "It is extremely rare in my part of the world."

Former Vice President Mike Pence, U.S. Senator Tim Scott and others are also trying to make a play for Iowa, and it remains possible that a splintered field could help Trump to win.

DeSantis is scheduled to visit Iowa on Friday, his third trip to the state since declaring his presidential bid. His wife, Casey DeSantis, last week traveled to Iowa to launch a national "Mamas for DeSantis" campaign focused on parental rights, hoping to win over the swing vote of suburban Republican women.

The DeSantis campaign is hoping that the governor, who has made hot-button, conservative social issues the centerpiece of his campaign, will find favor with the state's typical Republican voting mix of evangelical Christians, Lutherans and Catholics.

New Hampshire and Nevada, whose primaries are due to take place after Iowa, are less religious and are seen as less likely to reward his hardline stances.

DeSantis' supporters are also emphasizing what they see as the similarities between DeSantis and Kim Reynolds, Iowa's popular Republican governor, said one person close to the campaign. Reynolds has been a frequent guest at DeSantis' events, causing Trump to lash out at her.

TRUMP LOOMS

Along with the intense focus on Iowa, the DeSantis campaign is also simply crossing its fingers and hoping that Trump may yet be weakened by one of the existing indictments against him for making hush money payments to a porn star and mishandling classified documents or by new ones relating to his actions to overturn the 2020 election.

Trump, however, owns a deep reservoir of support in Iowa, where he was widely popular as president.

His team has knocked on some 30,000 doors in the state and has over a dozen staffers there, two campaign strategists told Reuters. And Trump himself has traveled to Iowa at least three times since declaring his presidential run.

"The campaign has the most sophisticated and experienced team ever in Iowa, and is poised to crush DeSantis," Trump spokesperson Steven Cheung said.

A dearth of reliable polling in Iowa makes it difficult to assess the real strength of both DeSantis and Trump in the state.

J. Ann Selzer, a veteran pollster in the state, said the race remains wide open with six months to go.

"Recent caucuses have been political mayhem. It used to be the front-runner stayed the front-runner," Selzer said. "What I say about the caucuses is that anything could happen and probably will."