On roller-coaster day, Gingrich braces for ex-wife interview while picking up Perry endorsement

In perhaps the most tumultuous day of his presidential bid, Republican contender Newt Gingrich faced chart-spanning highs and lows Thursday with a coveted endorsement from a former rival and accusations from his ex-wife that he sought permission to keep a mistress on the side.

As a string of new polls showed him in striking distance of Mitt Romney in South Carolina two days before that state's primary, Gingrich won the backing of Rick Perry, the one-time front-runner whose campaign fizzled after poor debate performances despite high expectations. Acknowledging he couldn't win, Perry dropped out of the race and threw his support to his longtime friend, the former House speaker.

Perry called Gingrich a "conservative visionary who can transform our country."

"I have no question that Newt Gingrich has the heart of a conservative reformer, the ability to rally and captivate the conservative movement, the courage to tell those Washington interests to take a hike if that's what's in the best interest of our country," Perry said.

But hours before Perry's forceful statement, Gingrich was already on alert for a coming interview in which ex-wife Marianne Gingrich, whom Gingrich divorced in 2000, claimed that her ex had wanted an "open marriage."

More On This...

"He was asking to have an open marriage and I refused ... that I accept the fact that he has somebody else in his life," Marianne Gingrich told ABC News. "That is not a marriage."

Gingrich, who in 2001 married Callista Bisek, the woman he was seeing at the end of his marriage to Marianne, said Thursday he would not speak about his ex-wife. A converted Catholic, he said that he has already sought the forgiveness he needs. His daughters also released a letter sent to ABC News saying that divorce takes an emotional toll on everyone involved.

"Anyone who has had that experience understands it is a personal tragedy filled with regrets, and sometimes differing memories of events. We will not say anything negative about our father's ex-wife," they said. "He has said before, privately and publicly, that he regrets any pain he may have caused in the past to people he loves."

Ahead of another presidential debate in a field that has now narrowed to four, Gingrich, unbowed by the revelations, was buoyed by fresh polling showing him decidedly on the upswing in South Carolina just two days before Saturday's primary.

At least four new polls, all taken following Gingrich's strong debate performance on Monday, showed Gingrich leading Romney by a narrow margin in the Palmetto State.

An American Research Group poll showed Gingrich with 33 percent in South Carolina, followed by Romney with 32 percent. The poll of 600 likely primary voters was taken Jan. 17-18 and had a margin of error of 4 percentage points.

A Rasmussen Reports poll Thursday showed Gingrich with 33 percent and Romney with 31 percent. The same poll showed Ron Paul with 15 percent and Rick Santorum with 11 percent.

"We're going to do everything we can do to convince every conservative voter in South Carolina to vote for me as the only practical way to stop a Massachusetts moderate," Gingrich said Thursday. "I think the increase in the polling indicates that I'm the only conservative who has a chance to beat Romney."

But with the day focusing on Gingrich's trials and tribulations, the other candidates also had their moments to shine Thursday.

The Iowa Republican Party released certified results from their caucuses showing Rick Santorum leading Romney in that contest, though Romney initially had been declared the winner. The Iowa GOP showed Santorum leading that contest by 34 votes though the party was still missing results from eight precincts and would not declare an official winner.

Romney called Santorum to congratulate him on the outcome, which Santorum's camp said it took as a concession, but the Romney camp described as merely a friendly gesture.

With Gingrich pitching himself as the conservative to beat Romney, Santorum is trying to muster a last-minute surge of his own, as he did in Iowa. Speaking before the Southern Republican Leadership Conference in Charleston, he described himself as a "conviction conservative" and someone "who can rally the base of our party."

"I have no apologies for the strong positions I've taken over the years, and they've been consistent," Santorum said.

He went on to take several shots at Gingrich and Romney, criticizing them for previously supporting the idea of a so-called individual mandate -- a requirement to buy health insurance, something neither candidate currently supports on the federal level.

"How are we going to differentiate ourselves on the major issues of the day if we nominate Tweedledum and Tweedledee?" he said. "South Carolina can speak loudly that we want clear, bold contrasts. ... We have one state under our belt, and now we have an opportunity to surprise again."

Santorum's campaign also rolled out the endorsement of social conservative leader James Dobson, founder of Focus on the Family. Dobson, in a statement, said Santorum "is the one who has spoken passionately in every debate about" family.

Elsewhere, The State newspaper, South Carolina's largest daily, endorsed Romney, after initially throwing its support behind Jon Huntsman, the former Utah governor who bowed out on Monday.

Paul, who placed second in the New Hampshire primary, held a rally with 800 students Thursday at the College of Charleston.

Former presidential candidate Herman Cain also revealed Thursday what he described as his "unconventional endorsement" -- for "the people."

"We the people of this nation are still in charge," he said. "I'm endorsing the people."