DES MOINES, Iowa >> One volunteer leader enlisted by Donald J. Trump to turn out Iowa voters has yet to knock on a single door or to make a phone call. Another is a “9/11 truther” with a website claiming that the Sept. 11 attacks were a government conspiracy. A third caucus precinct captain, who like the others attended a training session in West Des Moines last month, said the campaign’s goal of having them each enlist 25 supporters was unrealistic.

“There’s probably not even 25 registered voters in a precinct,” said the captain, Kathy Hawk, a retired trauma therapist in Ottumwa, who began making calls only on Monday.

Trump, who Iowa polls show is neck-and-neck with Sen. Ted Cruz of Texas, may well win the caucuses, now less than three weeks away. But if he does, it will probably be in spite of his organizing team, which after months of scattershot efforts led by a paid staff of more than a dozen people, still seems amateurish and halting, committing basic organizing errors.

Some volunteers in charge of turning out supporters to caucus on Feb. 1 are given lists of all registered Republicans in their precincts to contact, ignoring the large number of independents and Democrats who appear to be leaning toward Trump. Moreover, the volunteers urge people to caucus regardless of whom they support, which risks turning out voters for Trump’s rivals.

“I got 12 to go to the caucus, but I don’t know if they will actually vote for Donald Trump,” said Rick Shaddock, a precinct captain in Fairfield and the one who maintains the Sept. 11 conspiracy site.

Shaddock said one of Trump’s senior Iowa operatives, Marshall Critchfield, had told him not to bring up his conspiracy views when calling voters.

“Marshall took me aside and told me, ‘Rick, when you’re talking to people about Donald Trump, maybe you shouldn’t mention 9/11,’” he said.

Compared with the well-oiled machines of other leading candidates in both parties, particularly that of the Cruz campaign, the Trump ground game in Iowa seems partly an afterthought, as if Trump’s strategy is to leverage his charisma — the appeal that draws thousands to his rallies — to motivate voters.

But the challenge in Iowa is that historically, caucusgoers — only a sliver of registered voters — have had to be coaxed out by a field team, rather than be counted on to show up and vote on their own. This is especially true of the demographic that supports Trump: younger voters and others with a low propensity to turn out.

As temperatures plunged to single digits over the weekend, canvassers for Hillary Clinton posted pictures of themselves on social media going door to door in the snow. Meanwhile, Trump’s volunteers in Davenport, a city where the campaign appears to be better organized than elsewhere, decided it was too cold to go out.

Seven volunteers worked the phones at the Iowa headquarters of Sen. Marco Rubio of Florida in a Des Moines suburb one evening last week. At the state headquarters of Cruz, there were 24 volunteers in a room beneath a sign proclaiming a daily goal of making 6,000 calls. The Trump state headquarters in West Des Moines were largely deserted.

Asked for comment about Trump’s Iowa organizing, a spokeswoman for the candidate, Hope Hicks, wrote in an email, “There is no one available to speak with you.”

There are some positive signs suggesting that Trump supporters, whose enthusiasm gives an electric charge to his rallies, may show up in large numbers on their own, defying caucus tradition.

Whereas attendees at Trump rallies last year were often noncommittal about caucusing, many at a rally in Ottumwa on Saturday said they would caucus for Trump even though they had little idea what was required.

Linda Vogt, a retired schoolteacher, said that she would turn out for Trump, and that it would be her first time as a caucus participant. “Maybe I never paid attention before,” she said. “I’m worried about the terror and the debt. I’m worried the terrorists will come here now.”

Phil Cavanaugh, a chairman of the Wapello County Republican Party, said he feared that the Ottumwa High School auditorium, which drew 1,200 people for previous Republican caucuses, would be too small for the 2,000 he expected this year. He said many candidates, including Sen. Rand Paul of Kentucky and former Gov. Mike Huckabee of Arkansas, had drawn large crowds in recent visits to Ottumwa, a small city about 90 miles southeast of Des Moines.

“We brought a neighbor who hasn’t caucused in over 30 years,” Cavanaugh said at the Trump rally. “She’s going to caucus with us.”

As people streamed in, a Trump field representative, Elizabeth Mae Davidson, sought to enlist volunteers as precinct leaders.

“What does that entail?” asked Selena Jacobs, who had never caucused before.

“You stand up and say why you want to support Mr. Trump,” Davidson said.

“Hmm,” Jacobs replied, adding that she was not sure she would speak well in public.

“I think you would, you’re pretty,” Davidson said. “We’ll give you a script to read. We’ll have trainings here locally.”

Jacobs was not convinced, but she said she planned to attend the caucus to vote for Trump.

“Awesome,” the staff member said.

Davidson, based in Davenport, where on Sunday she opened only the second field office in the state for Trump, is one of the campaign’s most effective organizers. She has recruited captains for nearly all of the 65 precincts in Scott County, in many cases more than one captain per precinct.

But Davenport appears to be a bright spot compared with other regions of Iowa, like rural Brooklyn, where the Trump precinct captain Clair Kuntz said he had not made any effort to contact people.

“When I call, it’s not going to be any more than a week out,” he said, adding that he had yet to receive fliers describing Trump’s positions, a basic canvassing tool that campaigns provide.

In Fairfield, in southeast Iowa, Shaddock, the 9/11 skeptic, said it would be difficult to find someone to speak publicly on Trump’s behalf in each of the eight precincts in the area. He asked the Trump campaign for $500 to rent the Fairfield Arts and Convention Center so all precincts could caucus together, which would require just one speaker. The campaign turned him down. “Donald himself could have spent $500,” he said.

A computer network installer, Shaddock said he was disturbed by Trump’s comments about Muslims. “It comes across as bigoted,” he said. “I have customers who are Muslims.”

Although he was not at the Ottumwa rally, Shaddock said that he would have stood up to object when Trump referred to Muslims flying planes into the World Trade Center on Sept. 11, 2001.

“That hasn’t been proven,” he said. “I would have stood up and said, ‘Listen, it was remote-controlled takeover of the autoland’” technology.

Shaddock’s outspokenness on these views, which the campaign has asked him to rein in, was not tested on Tuesday night as he placed calls to voters. Using an app, Ground Game 2, supplied by the Trump campaign, which also provided a list of prospects in his precinct, he placed calls to all eight names — as many as he had been given for the day by Trump headquarters.

Six times he reached voicemails. Another number was not in service. At the one number he reached, a woman picked up, and Shaddock asked to speak to the voter on his list, a man.

“I don’t know that person,” the woman said.

“I did dial the correct number, right?” Shaddock asked.

The woman hung up.