On Wednesday, the Florida governor began a breakneck stretch of campaign events in the run-up to Iowa's Jan. 15 caucuses, which will offer the first signal of whether Republican voter preferences match public polling that shows former President Donald Trump as the party's runaway frontrunner.

No candidate has staked more on a strong result in Iowa than DeSantis: He visited all 99 counties in the state, fiercely courted its socially conservative voters and secured the backing of its governor.

Associates of the governor say he needs at least a second-place finish in Iowa, and a poor showing there would likely doom his bid. The next Republican nominating contest comes Jan. 23 in New Hampshire, where he has been lagging in polls behind Trump and former United Nations ambassador Nikki Haley.

At an event in a small community center in Waukee, Iowa, on Wednesday, DeSantis peppered his remarks with criticism of Trump, contending that he failed to follow through on his campaign promises, including building a wall on the U.S. southern border and deporting millions of migrants in the country illegally.

"What makes you think somehow he's gonna get it done the second time around?" DeSantis asked the crowd of about 100 people.

One attendee, Christopher Garcia, 75, of Woodward, Iowa, challenged DeSantis, noting that he was faring poorly in polls and pushing him to go more "directly after" Trump. He cited Trump's attacks on the late U.S. Senator John McCain, arguing that it had harmed the party's standing with veterans.

DeSantis took exception, cutting him off and maintaining that he has been tough on Trump. After a further back and forth with Garcia, DeSantis conceded the point that Trump "has been his own worst enemy."

Since the early days of the campaign, DeSantis, Haley and other Republican aspirants have largely stayed cagey about criticizing Trump, recognizing that they would need some of Trump's voters to win the nomination.

However, Trump has been less reticent about mocking them, creating the impression at times that he had cowed the field into silence.

Afterward in an interview, Garcia said he would caucus for DeSantis, complaining that Trump "can't keep his mouth shut."

"We need somebody in there who can be president. DeSantis would be fine, but he's got to fight," he said. "Are these people afraid to take Trump head-on? Is that the problem?"

The Republican nominee will face Democratic President Joe Biden in the November election.

Another attendee, Tom Shields, 78, of Clive, Iowa, said he also will caucus for DeSantis after supporting Trump in the past.

Trump "comes on pretty strong, and I think he turns a lot of people off," Shields said.

LATE IN THE GAME

DeSantis' campaign has been plagued by money woes and discord between his campaign staff and a super PAC supporting him, Never Back Down. But more fundamentally, he has struggled to expand his appeal beyond a narrow slice of the Republican electorate and position himself as an heir to Trump's political movement.

At a campaign rally for supporters on New Year's Eve, DeSantis' most influential evangelical supporter, Bob Vander Plaats, urged those in the room to not surrender. "Everywhere I go, the polls don't match up with reality," he said.

Those close to DeSantis or his nomination effort privately acknowledge that he needs to finish in at least second in Iowa to keep his candidacy viable.

One person who speaks with the governor frequently said even a close finish that results in both DeSantis and Haley coming away with the same number of delegates would be a defeat. The 40 delegates up for grabs in Iowa are awarded on a proportional basis.

"We're hoping that we're going to surprise everyone," said that person, who requested anonymity to speak frankly about the state of the campaign. "If he gets the same amount of delegates, that's bad."

One major donor, who has spent more than $1 million supporting DeSantis, said a third-place finish would be the end of the campaign.

In the run-up to Iowa, Haley and the super PAC backing her have been outspending both DeSantis and Trump. The PAC, SFA Fund Inc, has blanketed TV airwaves with negative ads against DeSantis while leaving Trump alone.

Haley returns to Iowa on Thursday for a televised town hall with voters. DeSantis will participate in a similar event that evening.

Before then, he will barnstorm the western part of the state on Wednesday holding several events, then do the same in the eastern region over Friday and Saturday, when Trump will also hold four rallies in Iowa.