EASLEY, S.C. (AP) — Former House Speaker Newt Gingrich said Thursday he's still the best conservative alternative to Mitt Romney for the Republican presidential nomination, brushing aside a report saying that a vote canvass in Iowa shows Rick Santorum ended up edging Romney in the state's GOP caucuses.

"If you look at your own poll, I'm clearly now within five points of beating Romney" in South Carolina," Gingrich told NBC's "Today" show in an early morning interview from South Carolina.

The Georgia Republican was asked about a report in the Des Moines Register Thursday, saying a canvass of the GOP caucuses showed that Santorum, a former Pennsylvania senator, actually defeated Romney by 34 votes. Initial reporting on Iowa gave Romney a razor-thin victory margin of eight votes.

In the interview, Gingrich Santorum "a fine person," but said he's running well behind in South Carolina, where the Republican hopefuls will debate later Thursday and voters go to the polls on Saturday.

On another issue, Gingrich declined to talk in detail about any damage to his campaign that might come from an interview that ABC News scheduled on its late-night program "Nightline" with his ex-wife, Marianne Gingrich.

"I'm not going to say anything bad about Marianne," Gingrich said. He did say that members of his family had written to ABC to complain about the broadcast, saying he thought it was wrong for the network to be "intruding into family things that are more than a decade old."

Asked if he thought his ex-wife could say things that would harm his prospects, Gingrich said his daughters are "credible" character witnesses.

Gingrich has been on an upswing in recent days, drawing big, enthusiastic crowds and fending off new attacks from Romney while reveling in a strong debate performance and a nod from tea party favorite Sarah Palin.

But it's unclear whether his latest burst of momentum, reflected in both internal and public polling, will be enough for him to overtake Romney. Complicating his effort are two other conservatives — Santorum and Rick Perry — who threaten to siphon his support.

ABC News has not indicated what Gingrich's ex-wife said in the interview, but the network planned to release excerpts ahead of Thursday night's GOP debate and "Nightline" broadcast.

The mere existence of the interview shines a spotlight on a part of Gingrich's past that could turn off Republican voters in a state filled with religious and cultural conservatives who may cringe at his two divorces and acknowledged infidelities.

Marianne Gingrich has said Gingrich proposed to her before the divorce from his first wife was final in 1981; they were married six months later. Her marriage to Gingrich ended in divorce in 2000, and Gingrich has admitted he'd already taken up with Callista Bisek, a former congressional aide who would become his third wife. The speaker who pilloried President Bill Clinton for his affair with Monica Lewinsky was himself having an affair at the time.

Underscoring the potential threat to his rise, Gingrich's campaign released a statement from his two daughters from his first marriage — Kathy Lubbers and Jackie Cushman — suggesting that Marianne Gingrich's comments may be suspect given the emotional toll divorce takes on everyone involved.

"Anyone who has had that experience understands it is a personal tragedy filled with regrets and sometimes differing memories of events," their statement said.

A CNN/Time South Carolina poll released Wednesday showed Gingrich in second place with support from 23 percent of likely primary voters, having gained 5 percentage points in the past two weeks. Romney led in the poll with 33 percent, but he had slipped some since the last survey. Santorum was in third place, narrowly ahead of Texas Rep. Ron Paul and well ahead of Perry.

Regardless of the South Carolina outcome, Gingrich was making plans to continue to Florida, which holds its primary Jan. 31.

"There is one candidate who can give you a conservative nominee and only one candidate who can stop Mitt Romney," Gingrich told an overflow crowd of about 400 at Mutt's BBQ in Easley on Wednesday. "A vote for anyone else is a vote that allows Mitt Romney to potentially be our nominee."

Confidence exudes from Gingrich, who rose in Iowa only to be knocked off course after sustaining $3 million in attack ads in Iowa from an outside group that supports Romney. Gingrich posted dismal showings in both Iowa and New Hampshire.

By the time the race turned to South Carolina, he was sharply criticizing Romney as a social moderate who is timid about attacking the nation's economic troubles. He also raised questions about Romney's experience as a venture capitalist, while a super PAC that supports Gingrich aggressively attacked Romney as a vicious corporate raider. And Gingrich ripped Romney for standing by as a super PAC run by former top Romney political aides continued to attack him in South Carolina.

Romney ended up on the defensive and by Monday night's debate, Gingrich was back in command. He earned a standing ovation when he labeled Democratic President Barack Obama "the best food stamp president in American history." The clip became the centerpiece of a television ad that began airing Wednesday as Gingrich worked to cast himself as the Republican with the best chance of beating Obama in the fall — stealing a page from Romney's playbook.

Said Gingrich senior adviser David Winston, "His taking on Barack Obama showed a toughness and an electability that the electorate is looking for."

On Tuesday, Palin, the 2008 GOP vice presidential nominee, announced that if she lived in South Carolina, she would vote for Gingrich to keep the Republican race going.

Since then, Romney's campaign, probably sensing Gingrich's rise and working to deflect from its own troubles, has been trying to undercut Gingrich's claim that he helped President Ronald Reagan create millions of jobs in the 1980s, likening it to "Al Gore taking credit for the Internet."

Romney also dispatched supporters to make the case that Gingrich is erratic and unreliable. A new Romney Web video features former Republican Rep. Susan Molinari of New York saying Gingrich lacked discipline and labeling his time as speaker "leadership by chaos."

Gingrich, for his part, has been helped by the fact that Santorum hasn't seemed able to capitalize on the endorsement of a group of influential Christian conservatives. Those who aren't backing the former Pennsylvania senator seem to be coming Gingrich's way.

Gingrich picked up the endorsement of Florence pastor William Monroe on Wednesday, after receiving the backing of former Perry supporter James Livingston, a retired Marine who had been featured in an advertisement for the Texas governor. Greenville businesswoman Vivian Wong, who had endorsed former Utah Gov. Jon Huntsman, threw her support to Gingrich on Sunday, the night Huntsman withdrew from the race.

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