Latecomer Fred Thompson, who hasn't officially entered the 2008 presidential race, is setting Republican pulses racing in this early voting state.

Thompson, 64, an actor and former Tennessee senator, has no serious political organization in South Carolina and makes his first appearance in this campaign season in the state on Wednesday. So it's a sign of Republicans' deep unease with the current field of 10 GOP candidates that conservative voters are watching Thompson with interest.

"I'm much more impressed with Thompson than I am with any of the others," said Claude Sandidge, a 67-year-old retired produce broker. Thompson has the "conservative principles that correlate with Ronald Reagan," he added.

Betty Jackson, 73, who has run the Sunset Grill, a meeting place for GOP faithful, for 34 years, explained: "We're hunting a true conservative. That's what we're doing. That's why we're waiting."

Thompson, she said, may be that candidate. "If our country needed defending, I think he would do it. But I also think that he would do something about the border situation," Jackson said.

Thompson, who is expected to declare his candidacy next month, easily sold out a Wednesday fundraiser for the state Republican Party. He will address the group but plans no other campaign-style events during his one-day visit.

A poll last week showed Thompson and former New York Mayor Rudy Giuliani fighting for the lead in South Carolina. It's not clear whether voters are drawn to Thompson because he is the new candidate on the block, or whether his growing popularity is a function of perceived flaws with the other top-tier contenders.

Giuliani's support for abortion rights chafes the core of the GOP here. Former Massachusetts Gov. Mitt Romney's Mormon religion has been questioned by Christian conservatives who wield sizable clout in the state party. Arizona Sen. John McCain riled those conservatives here in 2000, and more recently has found himself on the wrong side of immigration legislation from the perspective of many Republican voters.

"To be honest with you, it seems to be a personality thing," said Wyndham Owens, a 57-year-old builder from Wagener, S.C., who votes Republican. "From what little I've seen, he seems to be conservative, yet not stupid."

The lesser-known GOP candidates each have an appeal to constituencies within the GOP but are handicapped by doubts about their electability.

Still, harnessing voter enthusiasm will be difficult with no campaign in place, Thompson supporters said. The first priority: hiring a state campaign manager.

"It's still just a loose group of folks who want Fred to be the next president of the United States," explained GOP state Sen. Larry Grooms, a Thompson supporter. "To put together a campaign structure ... that'll be our task for the month of July."

The group is trying to convert state lawmakers and other Republican elected officials to Thompson even if they've already endorsed other candidates. The South Carolina GOP has said it will hold its primary before Florida's on Jan. 29, but has not set a final date.

"There's a lot of people that went on board early to different candidates. They seem to all indicate that Fred Thompson could be their second choice," said state Sen. Ray Cleary, another supporter.

The Giuliani, Romney and McCain campaigns say they aren't perturbed by the seemingly meteoric rise in Thompson's popularity.

"You always have a little boomlet when you're looking to get into the race," said Barry Wynn, a former state party chairman who chairs Giuliani's South Carolina campaign.

"I think one of his biggest problems may be that he's never really run anything," Wynn said. "He hasn't been a CEO. He hasn't been a governor. He hasn't been a mayor of the nation's largest city. What does he do as an executive when he's in charge?"