Newt Gingrich was last night on the brink of turning his late surge into a surprise victory in today's South Carolina Republican presidential primary.
The former House speaker overtook Mitt Romney in opinion polls after an explosive debate performance in which he dismissed discussion of his decade-old marital failings as "despicable".
His ascendancy saw Mr Romney's camp scrambling to lower expectations that the former Massachusetts governor could swiftly wrap up the contest to face Barack Obama in November's election.
Victory for Mr Gingrich (68), just days after Mr Romney's win in the Iowa Caucus was overturned following a recount, would re-open a contest that many had assumed was all but over.
Mr Gingrich appeared to have weathered the storm following the emergence of his second wife, Marianne, whose allegation that he requested an "open marriage" was met with a muted reaction by voters.
Asked to confront the charge at the start of Thursday night's televised debate, Mr Gingrich received a standing ovation after furiously attacking the moderator.
"I am appalled that you would begin a presidential debate on a topic like that," he told CNN's John King.
He said raising the issue shortly before the primary was "as close to despicable" as anything he could imagine.
Mr Gingrich eventually stated that the story was "false" but claimed "the elite media" were more interested in "protecting Barack Obama" than allowing Republicans to explain themselves.
Having been 10 points behind Mr Romney at the start of the week in South Carolina, Mr Gingrich now leads by one point, according to an aggregate of polls by RealClearPolitics.
Mr Romney played down hopes that he would wrap the contest up early. "I said from the very beginning that South Carolina is an uphill battle for a guy from Massachusetts," he said. "I knew that."
Stuart Stevens, Mr Romney's chief strategist, claimed it was "ridiculous" to describe defeat in socially conservative South Carolina as a blow to Mr Romney, a relative moderate. "It is amazing that he is in contention to win it," Mr Stevens said.
Mr Romney suffered another weak debate performance. For the first time in recent memory he was booed and heckled by the audience after ducking a question about whether he would agree to release several years' worth of tax returns.
"Maybe," Mr Romney said.
The former corporate buy-out chief, who has a fortune of $250m (€193m), repeatedly struggled to deal with the topic. He disclosed during the week that he paid income tax at 15pc -- a lower rate than most Americans.
Mr Romney also invited ridicule by claiming the country required a leader who had "lived on the real streets of America". He grew up in Bloomfield Heights, Michigan, one of America's five richest cities, and owns extensive properties in California and New Hampshire.
After today's primary, the candidates move on to Florida, which votes on January 31. (© Daily Telegraph, London)