Southern heat

After a particularly wild day in the Republican presidential process, four candidates-Mitt Romney, Newt Gingrich, Rick Santorum, and Ron Paul-were left to face each other at the final debate before the South Carolina primary Saturday.

On Thursday morning, Iowa certified its caucus results, showing that Santorum, in fact, won the state, rather than Romney. Then around midday, Rick Perry announced he was withdrawing from the race and endorsing Gingrich. ABC News also released excerpts from an interview with Marianne Gingrich, Newt Gingrich's second wife, where she said that Gingrich had asked her for an "open marriage," in order to accommodate his ongoing affair with a congressional staffer, who is now his third wife, Callista. Marianne Gingrich said her husband told her, "You need to share me."

At Thursday night's debate in Charleston, S.C., CNN moderator John King asked Gingrich about the allegation first thing in the debate, and Gingrich spat fire in his response.

"I am appalled that you would begin a presidential debate on a topic like that," he said, adding that the question was "as close to despicable as anything I can imagine." Gingrich called the allegations "trash" and said, "The story is false." The audience cheered for the former speaker of the House and gave him a standing ovation, his second in two debates in the Palmetto State this week.

While the other three candidates didn't go directly after Gingrich on the allegations related to his marital infidelity, all three mentioned their longtime marriages-each to one wife. King asked Santorum about Gingrich's line that he has sought forgiveness though his faith.

"I am a Christian, too, and I thank God for forgiveness," Santorum said. "These are issues of character for people to consider."

Since the South Carolina Republican presidential primary began in 1980, the strongly evangelical state has always given victory to an evangelical candidate-and the eventual party nominee. But on Saturday the state will choose between two frontrunners who are either Catholic (Gingrich) or Mormon (Romney). Paul, the lone evangelical left standing, is polling slightly better than Santorum, the other Catholic in the race, but all the polls are less reliable now that Perry has dropped out.

Though Gingrich grabbed the most attention at the beginning of the debate, Santorum performed strongly throughout, hammering both Romney and Gingrich. Santorum went after Romney for the healthcare law he signed as governor of Massachusetts, then attacked Gingrich for supporting the individual mandate, a core feature of the federal healthcare law that requires all Americans to buy health insurance. Santorum said Romney and Gingrich were "playing footsie with the left."

Gingrich returned that if he could easily debate President Obama for three hours, Lincoln-Douglas-style, on such issues. "You can't run rings around the facts, Newt," Santorum said. "Grandiosity has never been a problem for Newt Gingrich."

"You're right, I think grandiose thoughts," Gingrich replied. "We need big leadership to take on big projects."

Then Santorum, formerly both a congressman and senator from Pennsylvania, went for Gingrich's jugular, accusing him of poor leadership in Congress, like doing little initially to prevent the banking scandal that rocked the House in 1992.

"I served with him, I was there," Santorum said. "It was an idea a minute. No discipline. No ability to pull things together."

Gingrich said, "Each of us has a selective history that fits our interest."

The foursome scuffled over the abortion issue, too. Santorum said Romney had a bad record as governor, that Gingrich had pushed social issues to "the back of the bus" in the 2010 Pledge to America, and that Paul was wrong to consider it a state issue, even if he believes life begins at conception.

Romney had one of his strongest lines of the night when he addressed the questions surrounding his income and his tenure at Bain Capital. "I'm not going to apologize for being successful," he said. "What I have, I earned."

But throughout the two-hour debate, he did his best to float above the fray, saying when King asked what he regretted in his campaign thus far, "I would take back every moment that I've spent talking about these guys on this stage and talk about Barack Obama. … Any one of them would be a better president than the one we've got."

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