Charlie Neibergall, Associated Press
Republican presidential candidate former House Speaker Newt Gingrich makes his way to speak to a group of students, Wednesday, Dec. 14, 2011, at the University of Iowa College of Public Health in Iowa City, Iowa. has little choice but to rely on momentum to carry him to victory in the Iowa caucuses. Ahead in the Iowa polls, Gingrich is scrambling to build upon his skeleton campaign organization in a state where successful caucus candidates typically have enjoyed well-built machines aimed at turning out supporters.

DES MOINES, Iowa — Republican presidential candidate Newt Gingrich has little choice but to rely on momentum to carry him to victory in the Iowa caucuses.

He has a skeleton campaign organization in a state where successful caucus candidates typically have had well-built machines aimed at turning out supporters. To build a stronger operation with less than three weeks until the leadoff 2012 contest, he has to scramble.

The former House speaker is hoping the typical rules don't apply to him, in a campaign that already has been far from typical.

"You're not going to have a successful campaign in the caucuses on organization alone," said John Stineman, an uncommitted Iowa Republican who ran Steve Forbes' 2000 caucus campaign. "You have to have some heat. Newt's getting hot at the right time. It's a matter of whether he can sustain the heat."

Getting a winning share of support from caucusgoers in 1,774 precinct-level party meetings across the state on a cold, early January night requires some level of coordination, such as nailing down supporters in each of Iowa's 99 counties.

Gingrich, whose mass staff departures in June stunted his Iowa campaign, is trying to cobble together his Iowa team using emerging social media methods and time-tested grass-roots work.

He has only nine staffers in Iowa, fewer than most of his rivals. He opened his campaign office just two weeks ago, while others have had state headquarters for months. And while Gingrich's fundraising has picked up, he hasn't had the vast sums former Massachusetts Gov. Mitt Romney and Texas Gov. Rick Perry have had at their disposal.

But just as his late rise in Iowa has had more to do with his performance in the national debates than campaigning in the state, his Iowa organization is benefiting from the notice he's sparked nationally.

Gingrich has argued that his message, timing and the Internet can help him close the organizational gap.

His full-frontal attack on President Barack Obama has been what some GOP activists in Iowa say is the confrontational approach they've been looking for in a potential challenger to the well-funded incumbent.

Gingrich, who has asked his supporters to remain positive as he faces attacks, is on the air in Iowa with a positive spot. Time is running out for effective advertising messages to stick, with candidates unlikely to air attack ads over the holidays.

Gingrich's message attacking Obama and pledging a positive campaign versus his GOP rivals has helped bring potential supporters to his website. It's netted supporters around the country who have made, on average, 1,200 telephone calls per night to Iowa Republicans in the past week, Gingrich deputy Iowa director Katie Koberg said.

Through the same site, a dozen supporters from out of state have traveled to Iowa to log days helping the campaign, Koberg said.

It's a far cry from Texas Rep. Ron Paul's campaign, with its statewide supporter network that includes niche groups such as students and doctors.

Although Romney has campaigned in Iowa less often than he did four years ago, his team has kept after supporters of his 2008 campaign, a massive $10 million effort that earned him second place.

That year, former Arkansas Gov. Mike Huckabee won the caucuses with a threadbare staff. He was the overwhelming favorite of evangelical conservatives, who functioned as an influential network but were not necessarily organized by the Huckabee campaign.

Gingrich is not the unanimous favorite of evangelicals, but he has the momentum Huckabee did.

"You can't confuse organization with paid staff," said Tim Albrecht, who was Romney's 2008 Iowa campaign spokesman but is uncommitted this year. "Gingrich has a Huckabee quality to him — late getting in place but with a ready audience, those longtime caucus veterans who don't need any hand-holding to get them to caucus."

Given the fluidity demonstrated in Iowa polls, Gingrich could benefit from late-deciding caucusgoers. And he has picked up a number of key GOP activists. The campaign rolled out a list of them from across the state and different segments of the party late Wednesday, aimed at portraying Gingrich as a unifying candidate.

They include former Iowa Republican Party Chairman Ray Hoffmann and Dean Kleckner, former president of the American Farm Bureau Federation. Kleckner had been a top Iowa backer of Herman Cain before the Georgia businessman quit the race Dec. 3.

Another key pickup known for his organizational heft is Darryl Kearny, a former finance director of the Iowa Republican Party and now the key finance official for Polk County, Iowa's most populous.

"I realize they have a lot of catching up to do," said Kearny, who has amassed a massive Rolodex in his 30-plus years as an Iowa party activist and campaign operative. "But I'm networking with everyone I know, calling and emailing, trying to pass on the word about Newt."