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Newt Gingrich and Mitt Romney battled into the final moments of the South Carolina primary Saturday, taunting each other with campaign stunts as the candidates anxiously awaited the verdict from the first-in-the-South contest.

The state has a reputation as a tie-breaker in the Republican primaries, often setting the winner on a relatively smooth course to the nomination. But Saturday's contest seemed likely to complicate things. If Newt Gingrich wins, there will have been three distinct winners in the first three contests. If Romney pulls out a victory, it almost certainly will be a close one -- sending the candidates into Florida and beyond in the fight for delegates.

Exit polling Saturday evening showed voters torn between the two leading candidates.

Those who made up their minds late were breaking for Gingrich, and those who had decided early mostly were backing Romney. Late deciders outnumbered early deciders, though, 53-46 percent. Gingrich also had the advantage among voters who viewed the debates as important, while Romney was leading among those who don't put much stock in them. And Gingrich was leading among those who say it's important that a candidate shares their religious beliefs. Romney, a Mormon, was leading among those who care less about a candidate's religious affiliation.

After seeing the exit polls, Romney aides were downplaying expectations. Aides to Ron Paul also told Fox News they are expecting a fourth-place finish.

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Primary day Saturday was marked by tough rhetoric on both sides, previewing the race ahead.

In the morning, Gingrich all but called Romney chicken after the former Massachusetts governor came and went at a campaign stop where both candidates were expected to meet.

"Where's Mitt?" Gingrich said mockingly, as he arrived at a Greenville diner just minutes after Romney's bus rolled out.

In a coincidence of scheduling, both Romney and Gingrich had booked events at Tommy's Ham House shortly before 11 a.m. The campaigns only realized the issue a day earlier, though insisted they would not change their schedules.

However, Romney showed up 45 minutes early. He gave a pep talk to the crowd, casting himself as the "real world" candidate running against a field of Washington insiders. Then he left, missing Gingrich.

When Gingrich arrived, he ribbed his rival.

"I thought he was going to stay and maybe we'd have a little debate here this morning," Gingrich said. "So I'm kind of confused."

Gingrich, sounding increasingly confident about his chances in the South Carolina contest as newly released polls show him surging ahead of Romney, went on to tell the crowd they have a chance to nominate a "genuine conservative who can debate and who can take it to Barack Obama."

Not to be outdone, Romney's campaign later put out a statement celebrating the "15th anniversary" of the House decision to reprimand Gingrich for ethics violations, during his days as speaker. The Romney campaign plans to deliver an anniversary cake to Gingrich's South Carolina headquarters to mark the occasion on Saturday.

A new poll released overnight from Public Policy Polling showed Gingrich leading Romney, 37-to-28 percent in South Carolina. The poll of 1,540 likely GOP primary voters was taken between Wednesday and Friday, which would cover Thursday's debate and the airing of an interview in which Gingrich's second wife claimed he sought an open marriage -- a claim he denied.

That poll, and another, suggest Gingrich was not heavily damaged by the allegation. An American Research Group survey taken Thursday and Friday of 600 likely primary voters showed Gingrich leading with 40 percent, followed by Romney with 26 percent.

In that survey, Paul pulled in 18 percent, followed by Rick Santorum with 13 percent.

Romney suggested Saturday morning in Greenville that he's girding for a drawn-out election, while sounding optimistic about his odds in the long run.

"We're going to work tirelessly to make sure we win this thing, not just (in South Carolina). We'd like to win here, of course, but we have a long way to go, so come join us in Florida, then in Nevada, Michigan, Colorado," he said. "We have a long way to go. We need to get 1,150 delegates, we're off to a good start."

On the final day, Gingrich and Romney sparred over each other's call to release detailed personal records.

Gingrich on Saturday rejected calls by Romney for him to release extensive information about the ethics investigation while he was House speaker. Gingrich dismissed the demand as a ploy to "divert" from the fact Romney has not committed to releasing his tax returns before April.

"Don't you sort of admire the arrogance and dishonesty of the Romney campaign?" Gingrich said. "They can't release their tax records. They're hiding. He can't even answer coherently (at) a debate. ... Until he files his tax returns, I'm not going to take anything he says seriously about being open."

While speaker, Gingrich was fined $300,000 for ethics violations, though he was cleared of many allegations. Though Gingrich said the ethics information is "out in the open" and has been for years, Romney's campaign suggested he should release more so voters can be confident there's no "October surprise" -- in other words, a cache of information that could be used against him by President Obama in a general election.

Romney acknowledged Friday that the race had tightened considerably. He said he's optimistic, but was not predicting victory.

Romney's fortunes have taken a sharp turn over the past week. He initially headed into South Carolina with a win in Iowa and New Hampshire under his belt, listening to political pundits talk about how he might wrap up the nomination in South Carolina.

Then the Iowa GOP announced that Rick Santorum, and not Romney, had actually won the Iowa caucuses -- party officials declared Santorum the winner late Friday night after giving a qualified announcement earlier in the week. Rick Perry also dropped out on Thursday, endorsing Gingrich.

And while Gingrich has deflected questions about the claims made by his second wife, Romney has struggled to explain why he won't release his tax returns in the near future.

Meanwhile, Santorum and Paul appear to be fighting for third place in the state.

Santorum, on Fox News, disputed Gingrich's description of himself as a "Reagan conservative."

He criticized Gingrich for his past support of an individual mandate -- the requirement to buy health insurance that is at the heart of the federal health care overhaul -- and of the financial industry bailout.

Santorum argued that neither Romney nor Gingrich is what the GOP needs in a nominee.

"Mitt Romney is a moderate, someone who is timid in his tax plan, timid in his approach to cleaning up Washington and reducing the budget deficit," he said. "And Newt Gingrich is, you know, unpredictable."

"We don't need either of those things," Santorum said. He added, in reference to his trademark attire, "We need ... the guy with the sweater vest that everybody trusts."