COLUMBIA, S.C. – As the time for attacks and stump speeches and bus fumes nears an end in South Carolina, the two leading contenders for Saturday's Republican presidential primary here sought a final surge of Palmetto State magic.

Newt Gingrich and Mitt Romney, one of whom will almost certainly emerge Saturday night with a crucial victory, dealt with a variety of crises while also trying to make closing arguments to voters in a conservative state. While Romney seemed to have the state locked up just a week ago, Gingrich has made a furious push to take a slim lead according to a pair of South Carolina polls released Friday. Both surveys showed at least 20 percent of Republican voters remain undecided, making Friday one of the most pivotal days yet in the Republican race for president.

Gingrich, the former Georgia congressman and speaker of the U.S. House, was still glowing from a pair of fiery debate performances this week. He kept up the heat on Romney.

“Tell your friends and neighbors that if we get every conservative to decide Newt Gingrich is the right person to stop a Massachusetts moderate, we will win by a surprising margin," Gingrich told nearly 500 supporters in Orangeburg, about 45 minutes southeast of the state capital.

Romney kept his public focus on President Barack Obama while speaking in the rain to nearly 300 people in Gilbert, a 30-minute drive west of Columbia.

"Three years ago [Obama] was on the ‘Today' show and said if I can't get this economy turned around in three years I'm looking at a one-term proposition," Romney said to huge cheers at Harmon's Tree Farm. "He is. We're taking it back. This is a president that failed."

After retreating from the elements, Romney acknowledged the tightening race.

"Frankly, to be in a neck-and-neck race at this last moment is kind of exciting," Romney told reporters.

Meanwhile, South Carolina's reputation as a haven for political dirty tricks reared its ugly head. An email, purported to be an official CNN breaking news alert, surfaced that claimed Marianne Gingrich, the candidate's second ex-wife, alleged he "forced her to abort a pregnancy conceived during the affair that preceded her marriage to Gingrich," according to a copy of the message obtained by The Atlanta Journal-Constitution.

CNN said on air Friday the email was a fake.. The AJC also obtained a copy of a second fake e-mail sent to Gingrich supporters that appears to be a message from Gingrich confessing to the charge.

“It is an unfortunate fact that there are elements in American politics who are negative, dishonest and, I will use the word, despicable… If we could find out who they are, I would urge the government to prosecute," Gingrich said.

Marianne Gingrich's Thursday ABC News interview, in which she claimed Gingrich wanted an "open marriage," remained a topic of conversation.

Gingrich angrily denounced the allegations in Thursday's debate and said the couple's friends at the time said it was not true.

In Orangeburg, several voters said they still support Gingrich despite the allegations from his ex-wife.

“He has asked for forgiveness and I am a Christian and I believe in giving him forgiveness,” said Karen Roquemore, of Orangeburg. “Let’s cut that issue and go on to something else.”

But voters who braved the rain to see Romney had differing views.

"It affected me," Robert Parrott, 55, of Columbia, said. "He said there are friends of his that can vouch for it. I kind of don't believe it. Were they there when it took place? I doubt it."

Parrott is supporting Romney, the former governor of Massachusetts and financier.

But as the most recent polls showed many South Carolina voters still undecided, Romney was unable to close the deal with at least one on Friday.

Glenda Dieterly, 42, of nearby Lexington, said she braved the weather to hear Romney. She said before Romney spoke that she was undecided.

After listening to Romney, Dieterly said she was ... still undecided.

"I thought he was very personable. I liked the way he presented himself," she said. "I’m still undecided though."

Dieterly said Gingrich's background of three marriages and allegations of affairs gives her pause.

"A pattern of behavior in their life and their marriage is something that concerns me as well about Newt Gingrich," she said.

Bob Horton, of North Charleston, was at a Gingrich event and said he almost wished the two candidates could be merged.

“Romney is my business man,” he said. “Newt is my foreign policy man.”

Gingrich made his first campaign stop at the Children’s Hospital in Charleston. He spoke with the medical staff there and watched his wife, Callista Gingrich, read her children’s book, “Sweet Land of Liberty,” to some of the young patients in a bright and airy atrium. More than 50 journalists crammed into the atrium to report on the event.

At one point, Gingrich looked up and smiled brightly at some of the doctors and nurses gazing at him through a window. They had posted a handwritten sign on the window that said: “Newt we love you.”

Among the people Gingrich spoke with was Dr. Scott Russell, the medical director of the pediatric emergency department. Russell, who grew up in Norcross, said he likes Gingrich because he supports funding medical research. He also praised the former congressman’s performance in Thursday’s debate.

“His debate skills are pretty legendary,” Russell said. “I thought he did a good job. That is his forum that he succeeds in.”

Gingrich and Romney kept up a serve-and-volley of attacks and responses throughout the day. Romney told reporters that Gingrich should ask that documents from the congressional ethics investigation into his actions in the 1990s should be released.

“He was pushed out of the House by his fellow members,” Romney said. “I think over 80 percent of Republican congressmen voted to reprimand the speaker of the House for the first time in history.”

Gingrich scoffed at Romney's charge.

Romney, Gingrich said,  “could have today released his tax records so the voters of South Carolina could discover something. I refuse to take seriously any request by the Romney campaign to disclose anything.”