NORTH CHARLESTON, S.C. (AP) — The race for the Republican presidential nomination took a turn toward the South Carolina surreal Thursday as Rick Perry dropped out, Newt Gingrich faced stunning allegations from an ex-wife and Mitt Romney struggled to maintain a shaky front-runner's standing.

An aggressive evening debate capped the bewildering day.

See also: Meet the GOP presidential candidates.

Former Sen. Rick Santorum played aggressor for much of the night, trying to inject himself into what seemed increasingly like a two-way race with little more than a day remaining until the South Carolina polls open on Saturday. He accused Gingrich and Romney of "playing footsies with the left" when it came to health care. Both men rejected the allegations.

The debate began a few hours after first word that Romney had been stripped of his Iowa caucus victory, only to be stung a few hours later by Perry's withdrawal and endorsement of Gingrich.

Gingrich, in turn, was accused by an ex-wife of seeking an open marriage so he could keep his mistress.

"Newt's not perfect, but who among us is," said Perry, abruptly quitting the race just before the first-in-the-South primary.

His decision to end a once-promising candidacy left Romney, Gingrich, Santorum and Texas Rep. Ron Paul the remaining contenders in the race to pick a Republican to challenge Democratic President Barack Obama this fall.

Nine hours after Perry exited one stage, the four remaining contenders walked onto another for a final pre-primary debate.

Gingrich angrily denounced the news media for putting his ex-wife front and center in the final days of the race. "Let me be clear, the story is false," he said. Santorum, Romney and Paul steered well clear of the controversy. "Let's get onto the real issues, that's all I've got to say," said Romney, although he pointed out that he and his wife, Ann, have been married for 42 years.

The audience gave Gingrich a standing ovation when he assailed the media, a reaction he can only hope is reflected in voter sentiment on Saturday.

All four remaining GOP candidates lustily attacked Obama, while Santorum in particular sought to raise his own profile.

Introduced to the audience at the outset, he mentioned his change of fortunes in Iowa, where an evident eight-vote defeat in caucuses on Jan 3 was belated transformed into a 34-vote advantage — though the Iowa Republican Party did not declare a winner.

Santorum jabbed at both Gingrich and Romney, but seemed to focus more attention on the former. If Gingrich is the party nominee, he said, "you sort of have that worrisome moment that something's going to pop. And we can't afford that in a nominee."

In a reflection of the complex political dynamics of the race, first Gingrich and then Santorum challenged Romney over his well-documented switch of position on abortion. Once a supporter of a woman's life to choose, he now says he is "pro-life."

Next: Gingrich could be the candidate with momentum.>>