CHARLESTON, S.C. -- Newt Gingrich, seeking to maintain his momentum, tapped back into the deep reservoir of resentment in American conservatism Thursday night by lecturing a debate moderator for the second time this week.

It was another explosive moment to cap the most eventful day of the Republican primary season. Iowa's Republican party kicked off the day announcing that former Sen. Rick Santorum (R-Pa) had won the Jan. 3 caucuses, instead of former Massachusetts Gov. Mitt Romney. Texas Gov. Rick Perry withdrew from the race and endorsed Gingrich. And then it emerged that Gingrich's former wife, Marianne Gingrich, was accusing the former House speaker of asking her to take part in an "open marriage" to allow him to keep a mistress.

CNN 's John King, Thursday's debate moderator, chose to ask Gingrich about his ex-wife with his very first question of the night, setting off a volcanic reaction from the Georgia Republican. Gingrich fixed King with a vicious glare and chastised him like a boarding school headmaster reproving a wayward student.

"I think the destructive, vicious, negative nature of much of the news media makes it harder to govern this country, harder to attract decent people to run for public office," Gingrich said. "And I am appalled that you would begin a presidential debate on a topic like that."

Just as happened in Monday's debate in Myrtle Beach , when Gingrich went after welfare recipients and big government, the crowd in the debate hall rose and gave Gingrich a standing ovation. But Gingrich was not finished speaking, fully aware that he had been given an opportunity to increase the momentum that his explosive comments on Monday bestowed on his candidacy.

"Every person in here knows personal pain. Every person in here has had someone close to them go through painful things," Gingrich said. "To take an ex-wife and make it two days before the primary, a significant question in a presidential campaign, is as close to despicable as anything I can imagine.

"I am, frankly, astounded that CNN would take trash like that and use it to open a presidential debate," he said.

King was on his heels, and protested weakly that CNN had not been the first to report the story. That just opened the door wider for Gingrich.

"John, it was repeated by your network," replied Gingrich, visibly upset. "You chose to start the debate with it. Don't try to blame somebody else. You and your staff chose to start the debate with it."

Mid-lecture, Gingrich did actually address the accusation itself: "The story is false. Every personal friend I have who knew us in that period says the story was false," he said.

But then Gingrich went back to hitting the media, saying that ABC News didn't quote his friends because "they would like to attack any Republican."

"I'm tired of the elite media protecting Barack Obama by attacking Republicans ," Gingrich concluded, drawing more enthusiastic cheers inside the hall.

One of Gingrich's top backers in the state, Katon Dawson, derided Gingrich's ex-wife afterwards: "Marianne's been out there doing this for years," Dawson said.

Earlier in the day, Gingrich refused to even engage the issue , telling reporters he would not answer questions about it.

"I'm not going to say anything about Marianne ... I'm not getting involved," he said, adding that his daughters were willing to talk to the press about the issue.

Gingrich's two daughters, Kathy Lubbers and Jackie Cushman, told ABC News that their father had assured them that Marianne's accusations were false.

"We spoke with him about that, Brian, and he said it's simply not true," Lubbers told ABC. "The truth is our father and Marianne had a difficult marriage. They had a difficult divorce. ... The American people have moved on. Our father has moved on.

In the debate, it was CNN's decision to go with the "open marriage" question off the bat that gave Gingrich an easy out to hit them for having misplaced priorities and an outsized focus on the sensational.

Rep. Ron Paul (R-Texas) agreed with Gingrich's critique . Paul campaign chairman Jesse Benton said that "opening the CNN debate tonight with questions about the former speaker's personal life is highly inappropriate given the many serious issues this country faces."

But Benton, in a statement, said that Paul takes issue with "Gingrich's attacks on capitalism, the money he took from Freddie Mac and his support for TARP and the individual healthcare mandate."

"Our problem with Newt Gingrich is not that he lied to his wife, but that he lied to the American people," Benton said.

ABC was set to air the full interview with Marianne Gingrich late on Thursday after the debate concluded. As a result, Gingrich's messy personal past will continue to be a focus the day before the primary and into the weekend.

Tony Perkins, president of the Family Research Council, said that while Christian voters believe in forgiveness and redemption, the revelations about Gingrich's second divorce were of concern.

"As more of this comes out it's troubling," Perkins said.

But Randy Brinson, an evangelical organizer and founder of Redeem the Vote, said that his group has a list of 1.4 million South Carolina voters and was seeing a big move toward Gingrich among that constituency.

The Marianne Gingrich story "may backfire," Brinson said.

Romney's top aides were mum in the spin room after the debate. "I'm not going to touch it," adviser Stuart Stevens said when asked about the "open marriage" question and Gingrich's response.

"I'm not going to make any comment," said former Sen. Jim Talent (R-Mo.), who spent 20 minutes on a conference call this week bashing Gingrich's leadership in the House.

Privately, Romney aides were confident that while Gingrich got another standing ovation, his lashing out at King would hurt him.

One Romney adviser told The Huffington Post during the debate that Gingrich's comments were "good inside the hall, but will not work on Main Street, and main line churches."

And Austin Barbour, one of Romney's national finance chairmen, said that "a candidate's personal background should and is considered by voters."

"Personal principles matter to voters. Don't attack the moderator for trying to let the voters hear your response on issues that matter to voters," Barbour told HuffPost.

Another veteran Republican consultant in Washington called Gingrich's rebuke of King "very strong," but still predicted that "he comes up short in [South Carolina] and finishes number two."

Polls have shown Gingrich rapidly erasing Romney's double-digit lead over the past few days, and the race here looks like it will indeed come down to the wire. A CNN poll released late Thursday , however, showed Romney maintaining a 10-point lead, with 33 percent, compared with Gingrich's 23 percent.

Romney performed well in the debate, as he usually does, but again took some hits over his income tax returns. Gingrich's campaign released their candidate's returns at the beginning of the debate, guaranteeing that it would come up. And Romney said he will release his in April, the first time he has definitively said so.

"I'll release my returns in April, and probably for others years as well," Romney said.

King pressed Romney on why he wouldn't release past returns before the Saturday primary. When Romney equivocated, there were scattered boos in the audience.

Gingrich did not go unscathed. Santorum made the same argument against Gingrich that the Romney campaign has been making the past two days -- that Gingrich is too volatile and too undisciplined to be president.

"Grandiosity has never been a problem with Newt Gingrich, he handles it very, very well," Santorum said. "And that's really one of the issues here, folks. A month ago he was saying, 'It's inevitable that I'm going to win the election, I'm destined to do it.' I don't want a nominee that I have to worry about going out and getting the picture the next day and I have to worry about what he's going to say next. That's what I think we're seeing here.

"Newt's a friend, I love him, but at times you've just got, you know, sort of that worrisome moment that something's going to pop. We can't afford that in a nominee," Santorum said.

Gingrich responded by embracing Santorum's critique.

"You're right. I think grandiose thoughts," Gingrich said. "This is a grandiose country of big people doing big things. And we need leadership prepared to take on big projects."

The Romney campaign immediately sent out a research document titled, "I think grandiose thoughts." It chronicled Gingrich's past comparisons of himself to historical figures, including Ronald Reagan, Margaret Thatcher, Abraham Lincoln, Woodrow Wilson, Henry Clay, Charles de Gaulle, William Wallace, Pericles, the Duke of Wellington, Thomas Edison, Vince Lombardi, the Wright Brothers, and Moses.

Elise Foley contributed to this report.

Background on Newt Gingrich's campaign: