By MICHAEL FALCONE ( @michaelpfalcone ) and AMY WALTER ( @amyewalter )

CHARLESTON, S.C. - Newt Gingrich clearly owned the night with a strong showing on the debate stage in Charleston, but whether he wins primary day in South Carolina remains the big question.

Even though political observers here agree that Gingrich has a shot at the top prize in the Palmetto State, Mitt Romney is still well-positioned to walk away with a victory after all the votes are counted tomorrow.

All of Romney's remaining rivals - Gingrich, Rick Santorum and Ron Paul - have vowed to carry their campaigns on in the next state to vote, Florida, but everyone knows that a Romney win in South Carolina would represent a devastating blow to the rest of the field.

Gingrich could still eke out a win here if, as some polls suggest, he is beginning to consolidate the anti-Romney vote. He will reap at least some benefits from Rick Perry's decision to quit the race and it also appears he is finding support from other segments of the Republican Party.

"I think in South Carolina, from what I'm hearing, a lot of the Tea Party people are behind Newt," Tea Party leader Jenny Beth Martin told The Daily Caller's Alex Pappas in an interview after last night's debate. http://thedc.com/yp2NJb

But a number of South Carolina politicos The Note spoke to within the last 24 hours insist that Romney is still best positioned to do well here and that the Perry vote is likely to be split among several of the candidates rather than flow to Gingrich directly.

The four candidates will crisscross the state at a feverish pace today - the final full day of campaigning before tomorrow's primary.  And for many voters, the memory of last night's debate will still be fresh in their minds when they cast their ballots.

Here are ABC News Political Director Amy Walter's winners and losers from the evening: http://abcn.ws/AsMqta

WINNERS:

-Santorum: This was his strongest performance of the entire campaign. He was confident, polished and substantive. He was determined to fight Newt Gingrich for the mantle of the "conservative alternative" to Mitt Romney.

-Gingrich: The former Speaker dominated the first five minutes of the debate with his scathing attack on CNN moderator John King. King opened the debate by asking Gingrich to respond to allegations made by Gingrich's ex-wife Marianne in an interview with ABC News and the Washington Post that Gingrich encouraged her to enter into an open marriage. The question was an invitation for Gingrich to do what he does best - chastise the media.

MEH:

-Romney: After a halting performance in the Myrtle Beach earlier this week, Romney was more confident and poised. But, his rambling response on releasing his tax records elicited audible boos from the audience. Given the fact that this issue has dominated the race for the last week, it is surprising that he has yet to come up with a solid answer on this. Moreover, he continues to look uncomfortable when he tries to downplay his considerable wealth.

LOSERS:

-Mainstream Media: There is no fatter and more appealing target to an audience of conservative Republicans than the mainstream media. And, John King opened the floodgates tonight with his opening question to Gingrich about accusations from his ex-wife. The question only helped to sow the seeds of distrust among conservatives about the intentions of traditional media organizations.

-Ron Paul: Even though there were only four candidates on the stage last night, Paul faded into the background. Even Santorum and Gingrich, who have enjoyed sparring with the Texas Congressman in previous debates, essentially left him alone tonight - a sign that his relevance in this state is much more limited.

-Foreign Policy: Iran - and its threat of close the Straits of Hormuz - has been a big talking point on the campaign trail and in Washington. Still, we didn't hear about Iran - or any other foreign policy issue of any sort last night.

ABC News political analyst Matthew Dowd weighs in on the latest developments in the race for the GOP nomination ahead of tomorrow's critical primary. WATCH: http://abcn.ws/wIH2mQ

PRIMARY PRIMER: ABC's Elizabeth Hartfield has the details about why tomorrow's contest is so significant and what to expect: "Since 1980, no Republican has won the Presidential nomination without first winning South Carolina," Chad Connelly, chairman of the South Carolina GOP, told ABC News. "Our motto is, 'We Pick Presidents.'" Twenty-five delegates are up for grabs in Saturday's contest. That number represents a 50% reduction of their original 50 delegates. The state was penalized for moving its primary date ahead of Feb. 1, a move made to preserve South Carolina's status as the first primary in the South after Florida jumped the line and moved its primary date to Jan. 31. As of Jan. 1, 2012, South Carolina counted 2,722,344 registered voters - 79% of the voting eligible population of 3,434,551. In South Carolina, voters do not register by party, so any registered voter can participate in the Republican primary. Polls open at 7 a.m. and close at 7 p.m. (EST). Voters across the state will cast their votes using machines called "direct recording electronic voting machines" or "DRE's."

COUNTIES TO WATCH: Two key counties to watch out for in Saturday's primary are Greenville and Lexington. Located in the northwestern part of the state, Greenville is South Carolina's most populous county. The county has a history of favoring socially conservative candidates. George W. Bush dominated Greenville in 2000 with 58% of the vote, and Mike Huckabee carried it in 2008, with 29% of the vote to McCain's 26%. Romney received 17% of the votes in Greenville in 2008, and his performance in this cycle will be a telling mark of whether he's been able to successfully court the social conservative vote. Greenville will also provide a window into the Gingrich and Santorum battle, particularly in light of Rick Perry's recent departure from the race. The former Pennsylvania senator and the former House Speaker are both vying for that spot as the anti-Romney candidate around whom the socially conservative base coalesces.

THE BUZZ

GINGRICH'S EX-WIFE OPENS UP. "Newt Gingrich lacks the moral character to serve as President, his second ex-wife Marianne told ABC News, saying his campaign positions on the sanctity of marriage and the importance of family values do not square with what she saw during their 18 years of marriage," ABC News' Brian Ross and Rhonda Schwartz report. "In her first television interview since the 1999 divorce, to be broadcast tonight on Nightline, Marianne Gingrich, a self-described conservative Republican, said she is coming forward now so voters can know what she knows about Gingrich. In her most provocative comments, the ex-Mrs. Gingrich said Newt sought an 'open marriage' arrangement so he could have a mistress and a wife. She said when Gingrich admitted to a six-year affair with a Congressional aide, he asked her if she would share him with the other woman, Callista, who is now married to Gingrich. 'And I just stared at him and he said, 'Callista doesn't care what I do," Marianne Gingrich told ABC News. 'He wanted an open marriage and I refused.'" http://abcn.ws/xRwdon

NOTED: "Newt Gingrich's tax returns aren't the flashiest or the most complicated, but the former House speaker pulled in quite a few dollars in 2010," reports ABC's Chris Good. "Gingrich and his wife, Callista, made an adjusted gross income of $3,142,066 in 2010-most of it from one of Gingrich's companies, Gingrich Holdings, Inc., headquartered on K Street in downtown Washington, D.C.Gingrich's campaign released his 2010 returns during Thursday night's debate in South Carolina, after the candidate repeatedly called on Mitt Romney to release his 2010 returns during the latest leg of the GOP campaign." More highlights: http://abcn.ws/vZzim1

MITT ROMNEY ON HIS TAX RETURNS. "Mitt Romney suggested at yesterday's GOP presidential debate for the first time that he would 'probably' release his tax returns not only from 2011 but from previous years as well, but garnered boos from the crowd when he seemed to waver on the decision," ABC's Emily Friedman notes. "Romney's announcement came the same night that rival Newt Gingrich released his tax returns for 2010, showing he made $3.1 million, and paid 31 percent of his income on federal taxes. Romney has said he paid about a 15 percent tax rate. That is the rate for capital gains on investments. 'When my taxes are complete for this year, and I know that if I'm the nominee, the president is going to want to insist that I show what my income was this last year, so when they're completed this year in April, I will release my returns in April for his year, and probably for other years as well,' Romney said during the debate in Charleston, S.C., sponsored by CNN. But when pressed whether he'd follow the path of his father, George Romney, who released 12 years of taxes during his 1967 presidential bid, arguing that there might be a 'fluke' in just one year's results, Romney responded, 'Maybe.' 'I don't know how many years I'll release,' Romney said as the crowd booed. Romney paused and smiled." http://abcn.ws/wQsu6E

RICK SANTORUM'S RISE. "Rick Santorum arrived on Capitol Hill as a new member of Congress in January 1991, 32 years old and bristling with the impatience of a man looking to kick up a fuss. Eight months later, he got his chance when he learned of lawmaker overdrafts at the little-known House bank," The New York Times' Sheryl Gay Stolberg writes. "Over beers with rebellious Republican newcomers who became known as the Gang of Seven, Mr. Santorum helped plot a freshmen's revolt. They would take to the House floor, one by one, to shame Democratic leaders into releasing the check-bouncers' names. … That fight grew into 'Rubbergate,' a scandal that earned Mr. Santorum, who is now seeking the Republican nomination for president, a reputation as a reformer and helped land him in the Senate; there, he drew national attention as a pugnacious opponent of abortion and gay rights. … But a look at the arc of Mr. Santorum's political career, from his days as a fresh-faced College Republican to his bruising defeat for a third term in 2006, reveals a side of Mr. Santorum beyond that of reformer and abortion foe. He emerges as a savvy operator and sharp tactician, a climber who became a member of the Washington establishment that he had once railed against." http://nyti.ms/zc2O1J

HERMAN CAIN'S 'UNCONVENTIONAL' ENDORSEMENT. "Herman Cain gave his blessing Thursday to another force in the GOP race for president. But it wasn't another candidate," reports Politico's Emily Schultheis. "In a keynote speech here at the Southern Republican Leadership Conference, Cain finally unveiled his 'unconventional endorsement' - the people who will decide the race. The endorsement is a fitting coda to a candidacy that was nontraditional to begin with, but it's unclear what kind of traction such an announcement will give Cain in his bid to coalesce an enduring movement. 'Here is my unconventional endorsement: not a candidate seeking the nomination, not someone that's not running. My unconventional endorsement is the people,' he said. The former Godfather's Pizza CEO said he plans to continue advocating for his 9-9-9 tax plan because it was so popular among his supporters." http://politi.co/ze2J01

CONFESSIONS OF A CAMPAIGN OPERATIVE. Former Huntsman campaign spokesman Tim Miller pens an Op-Ed for Real Clear Politics this morning offering an assessment of "how strong of a campaign Governor Romney ran, and how he did it at a time that uniquely suits his background and character." Among Miller's insights about Romney and his campaign:  "He took his biggest potential hurdles - Romneycare and the flip-flopping tag - head on. He didn't apologize for his record or try to rewrite history. Instead he clearly and succinctly explained how his view on health care differed from President Obama's. … A favorite trope of political analysts each cycle is that technology has so changed the political landscape that the same old rules of politics no longer apply. The reality is just the opposite. Not only do they still apply; they are more important than ever. You can't win a campaign with Facebook posts. You can't win a campaign without negative television ads. You can't win a campaign while on a book tour or through satellite Fox News hits. You need to manage your message through television ads and traditional media in addition to on Fox and the web. The Romney campaign had a clear message across all mediums and quickly dispensed with any threats to that message." http://bit.ly/z0cshl

WHO'S TWEETING?

@OKnox : Romney pens "open letter" to South Carolina voters…campaign does another conf. call attacking Gingrich… #notworriedatall

 @2chambers : Chaffetz, Flake, Campbell blasting Gingrich's record on Romney camp conf call; claim he's "father of modern earmarks"

  @dgordon52 : 6 US troops were killed yesterday in Afghanistan. It is shameful that CNN didn't ask 1 question about the 10+ yr war at the debate.  #p2

@morningmoneyben : Wish there were cameras on all candidates all day and I had multiple screens to watch em. Its a popcorn-popping day in politics.

@pfeiffer44 : I have worked for President Obama for 5 years and until last night, I had no idea that he could sing

POLITICAL RADAR:

-Newt Gingrich starts his day addressing the Southern Republican Leadership Conference at the College of Charleston in South Carolina. Later, Gingrich will hold three town halls in Charleston, Orangeburg, and Mount Pleasant.

-Rick Santorum campaigns in Lexington, Fort Mill, and Boiling Springs with three "Faith, Family, and Freedom" town halls. Santorum heads to Charleston, South Carolina Friday night to address the Citadel's Patriot Dinner and receive the Patriots Award from the college.

-Mitt Romney is on the trail in Gilbert, South Carolina where he'll hold a rally to discuss jobs and the economy. He will appear with Virginia Gov. Bob McDonnell in Charleston and Romney will end his day in Greenville with a "Get out the Vote" event.

-Ron Paul will travel from Charleston to Columbia on Friday with seven events scheduled. Paul will make three  stops at area airports including the Greenville Downtown Airport and the Florence Regional Airport.

-Stephen Colbert and Herman Cain are getting in on the action in South Carolina with a "Rock Me Like a Herman Cain" rally at the College of Charleston.

-ABC's Josh Haskell (@HaskellBuzz)

 

DISPATCHES FROM THE TRAIL.   Check out our new political website OTUSNews.com ( www.Otusnews.com)  The Note ( http://abcnews.go.com/blogs/politics/the-note/) and ABC News/Politics ( http://abcnews.go.com/politics)  and follow our reporters in the field on Twitter:

Newt   Gingrich:  ABC's Elicia Dover ( @EliciaDover)

Jon   Huntsman:  ABC's Susan Archer ( @TheOnlyArcher)

Ron   Paul:  ABC's Jason Volack ( @Jason_Volack)

Rick   Perry:  ABC's Arlette Saenz ( @ArletteSaenz)

Mitt   Romney:  ABC's Emily Friedman ( @EmilyABC)

Rick   Santorum:  ABC's Shushannah Walshe ( @shushwalshe) and ABC's Russell Goldman ( @GoldmanRussell)

 

Check out The Note's Futures Calendar:  http://abcn.ws/ZI9gV

 

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