CHARLESTON, South Carolina (Reuters) - Newt Gingrich hit back forcefully on Thursday at an allegation that he asked his second wife to tolerate an "open marriage", angrily denying the claim at a presidential debate in South Carolina.
"I'm appalled that you would begin a presidential debate on a topic like that," Gingrich told the debate moderator, John King of CNN.
Gingrich's wife said in an interview the Republican presidential candidate asked her to have an "open marriage" while he was having an affair with another woman in the 1990s, a statement that might damage his chances in South Carolina's primary vote.
Gingrich's wife Marianne spoke to ABC News' Nightline in an interview to be aired on Thursday.
Gingrich, former speaker of the U.S. House of Representatives, is rising in the polls ahead of Saturday's primary vote in South Carolina in which he is campaigning as the conservative alternative to front-runner Mitt Romney.
The former congressman has made the media's coverage a frequent target during the 2012 campaign.
Gingrich called the claim that he asked Marianne to allow him to have a mistress "false."
"I'm tired of the elite media protecting Barack Obama," Gingrich said.
His Republican opponents were asked whether Gingrich's past infidelity should influence the campaign.
"Let's get on to the real issues," said Romney, the former Massachusetts governor.
Former Pennsylvania Senator Rick Santorum, who is challenging Gingrich for the votes of social conservatives, talked about faith.
"This country is a very forgiving country," Santorum said.
(Editing by Philip Barbara)
(Reporting By Samuel P. Jacobs)