EASLEY, S.C. (AP) -- Republican presidential candidate Newt Gingrich is drawing big, enthusiastic crowds and fending off new attacks from GOP front-runner Mitt Romney while reveling in a strong debate performance and a nod from tea party favorite Sarah Palin.
Now he's set to pick up the endorsement of Texas Gov. Rick Perry, who officials say is abandoning his presidential bid to back the former House speaker. Adding to the intrigue, a bus emblazoned with Herman Cain's name sat in the hotel parking lot where Perry was to speak and endorse Gingrich. Cain, a tea party favorite, dropped out of the race late last year.
For all the positive developments for Gingrich, it's unclear whether his latest burst of momentum, reflected in both internal and public polling, will be enough for him to overtake Romney in Saturday's South Carolina primary. Complicating his effort is another conservative -- Rick Santorum -- who threatens to siphon his support.
And now, just two days before South Carolina votes, Gingrich is facing a fresh challenge that could undercut his efforts to cast himself as the strongest conservative challenger to Romney.
ABC News said it will air Thursday night an interview with Gingrich's second wife on its late-night news program "Nightline." The network has not indicated what the ex-wife, Marianne Gingrich, said in the interview, but ABC planned to release excerpts ahead of Thursday night's GOP debate and "Nightline" itself.
In an interview Thursday with NBC's "Today" show, Gingrich declined to talk in detail about any damage to his campaign that might come from the interview.
"I'm not going to say anything bad about Marianne," Gingrich said, adding that he thought it was wrong for the network to be "intruding into family things that are more than a decade old."
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 marital 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 has seemed unable 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.
Beaumont reported from Columbia, S.C.