Gingrich surging, but faces tough questions

Newt Gingrich has made an incredible surge to become the frontrunner in South Carolina after finishing fourth in Iowa and fifth in New Hampshire, but in Thursday's debate he was under siege.

The very first question was about ex-wife Marianne Gingrich's allegation that the former House speaker wanted an open marriage.

"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. And I am appalled that you would begin a presidential debate on a topic like that," he said, slamming CNN, which hosted the debate.

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"Let me be quite clear. The story is false. Every personal friend I have who knew us in that period says the story was false."

The other candidates declined to pile on but the hit Gingrich hard on his record.

"You talk about all the things you did with Ronald Reagan and the Reagan revolution and the jobs created during the Reagan years and so forth. I looked at the Reagan diary. You're mentioned once in Ronald Reagan's diary," Mitt Romney said.

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Rick Santorum, who served under Gingrich in the House, attacked his leadership in Congress.

"It was an idea a minute, no discipline, no ability to be able to pull things together."

During the debate, Gingrich's campaign released his tax returns showing he made $3.1 million in 2010.

Romney also took some shots over his tax returns, which he said he would release in April. Earlier this week, he revealed that he pays an effective tax rate of around 15 percent since most of his income is investment-generated.

"I know the Democrats want to go after the fact that I've been successful. ... I'm not going to apologize for being successful," he said.

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    Jan Crawford is CBS News Chief Political and Legal Correspondent. She is from "Crossroads," Alabama.