Lisa Lockwood, a spokesman for Cain's campaign in Iowa, said he has the support of Dean Kleckner, a former state Farm Bureau president and a party activist, and Pottawattamie County Chairman Jeff Jorgenson.
By contrast, Romney, Perry, Bachmann and former Sen. Rick Santorum have netted endorsements from state lawmakers and local party officials whose own networks could potentially prove beneficial.
So far, Cain has not run television commercials in the state, unlike Bachmann, Perry and Rep. Ron Paul of Texas.
In South Carolina, which hosts the first Southern state caucus, Cain has a staff of four and shows evidence of grassroots support. He won a straw poll of 110 women at a state Federation of Republican Woman meeting last weekend, followed closely by former Speaker Newt Gingrich, Bachmann and Romney.
Perry appears to have the largest organization in the state, and enjoys the support of roughly a dozen state lawmakers as well as one member of the state's congressional delegation, Rep. Mark Mulvaney.
Nationally, Cain also lags several of his rivals in fundraising, based on reports filed through the end of September, the most recent available.
At the time, Perry, the Texas governor, reported cash on hand of $15 million. Romney, the former Massachusetts governor making his second presidential run, reported $14.6 million in the bank.
Cain's cash on hand was $1.3 million, and his filing indicated he was more reliant on small donors — those giving $200 or less — than either Romney or Perry.
While polls are notoriously fickle, particularly before the first ballots are cast in a presidential race, Cain shot up rapidly in recent weeks, largely at Perry's expense, and his aides were eager to circulate the results of a Washington Post survey taken as the sexual harassment controversy was unfolding.
It showed him in a statistical tie for first with Romney, who had 24 percent support to 23 for Cain. Perry had 13, followed by Gingrich with 12.
Seven in 10 Republicans polled said reports of the allegations don't matter when it comes to picking a candidate.
But in a sign of possible danger ahead, the poll found that Cain slipped to third place among those who see the accusations as serious, and Republican women were significantly more likely than men to say the allegations make them less apt to support the businessman. The survey found that support for Cain was basically steady over the four nights of interviewing, though new accusations were surfacing.
In South Carolina, LaDonna Riggs, chairwoman of the Spartanburg County Republican Party, said she had seen nothing so far that would cause party activists to abandon Cain. "You give me some substance to the questions and then we can talk," she said.
"If there's truth to it, then it could hurt him. But right now, it's just allegations," said Cyrus Hill, a 67-year-old retiree from Granger, Iowa. "Allegations aren't going to end him.
Dave Roszak, 51 and a resident of Clive, Iowa, said, "If it turns out he isn't being honest, it will take him down."
Associated Press writers Tom Beaumont and Phil Elliott in Iowa, Steve Peoples in New Hampshire and Jim Davenport in South Carolina contributed to this story.
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