COLUMBIA, S.C. -- Newt Gingrich, whose candidacy was left for dead in June and then again earlier this month, scored a stunning victory over Mitt Romney here that has reshaped the Republican presidential primary and called into question Romney's ability to win the nomination.

Gingrich crushed Romney, winning 40 percent of the vote to Romney's 28 percent, and taking 43 of the state's 46 counties. Former Sen. Rick Santorum (R-Pa.) received 17 percent and Rep. Ron Paul (R-Texas) came in fourth at 13 percent, according to the Associated Press.

"Thank you South Carolina! Help me deliver the knockout punch in Florida," Gingrich tweeted soon after the race was called, directing people to where they could give money to his campaign.

Later Gingrich used his 23-minute victory speech to build on the themes that drove his popularity through the roof in this Southern state: deep resentment among conservatives of the influence of liberals in the press and other cultural institutions.

"The American people feel that they have elites who have been trying for a half century to force us to quit being American," Gingrich said.

"The elites in Washington and New York have no understanding, no care, no concern, no reliability, and in fact, do not represent them at all," he said.

Gingrich did not mention Romney by name and referred to him only twice, once to praise him as "a good example of America," and a second time to point out that Romney has a much better financed campaign.

"People power with the right ideas beats big money," Gingrich said.

The primary now appears to be a two-man race. Gingrich, who was until very recently something of a one-man campaign, is riding a wave of genuine momentum that is buffeting the Romney machine. Gingrich has emerged as the fighter that many Republican voters want to see defeat President Obama. Former Massachusetts Gov. Romney has looked weak and uninspiring.

Former Sen. Bob Smith (R-N.H.), a surrogate for Gingrich, said his win would "set in motion a real conservative surge now that will take us through the primaries."

"This is a movement," Smith said. "This is a cause to change the direction of America and get back to the conservative values of Reagan."

The crowd at Gingrich's victory rally in the downtown Columbia Hilton was caught off-guard by how quickly the results were announced, but cheered enthusiastically. An hour later, as Romney was shown giving his concession speech on one wide-screen TV in the corner of the room, the crowd chanted, "Nah nah nah nah, nah nah nah nah, hey hey hey, goodbye!"

Gingrich's win in South Carolina capped off a remarkable week in politics that saw the former House Speaker from Georgia decimate Romney's 10-point lead in the state in just five days. The breath-taking turn of events was sparked by Gingrich's racially charged exchange with Fox News debate moderator Juan Williams on Monday night in Myrtle Beach.

From the moment that Gingrich slapped down Williams' questions about his attitude toward low-income blacks, and thousands in the debate hall stood and roared their approval -- several voters this week told The Huffington Post that Gingrich "put him in his place" -- Gingrich was on fire. By Tuesday morning, Gingrich knew something big was happening.

Gingrich pinpointed the Monday debate and another on Thursday -- where he rebuked CNN's John King for asking about accusations by his second ex-wife that he asked her for an "open marriage" -- as key moments in the week.

"In the two debates that we had here ... where people reacted so strongly to the news media, I think there was something very fundamental that I wish the powers that be in the news media would take seriously," Gingrich said.

"It's not that I am a good debater. It's that I articulate the deepest-felt values of the American people."

But the immediate question now is whether Gingrich's momentum continues in Florida. His win will undoubtedly reduce Romney's lead in the polls, which is currently 40 percent to Gingrich's 22 percent in the Real Clear Politics average.

But Florida is the first big primary state that requires vast amounts of money to reach voters through advertising, and which can logistically test even the best run campaigns. In addition to the polling, Romney has a decided edge going into Florida.

His campaign ran their first TV ad in the state on Jan. 3. Eight of Florida's 18 Republican members of Congress have endorsed Romney. And Romney himself will begin campaigning immediately in Florida on Sunday, holding an afternoon rally in Ormond Beach, just north of Orlando.

More than $7 million has already poured into Florida on Romney's behalf this month: $2.5 million in TV ads from his campaign, $1 million in mail, and a reported $3.6 million in TV from a super PAC supporting Romney. The super PAC, Restore Our Future, has also spent an unknown amount on mail in Florida.

One of the five main categories on the group's website is a "Florida Vote Center" that helps voters find their polling place or sign up for an absentee ballot.

In addition, about five percent of Florida's 4 million registered Republicans, almost 200,000 in all, have already voted by absentee ballot or in early voting. Gingrich's very recent rise didn't influence their vote. He has yet to go on TV in Florida and has done little in terms of mail and radio advertising.

"We're now three contests into a long primary season," Romney said in his concession speech. "We've still got a long way to go."

"I will compete in every single state."

However, Gingrich's strategy so far has been to provoke his way to earned media exposure, since he has not had the money to pay for it. And while risky, he has connected with Republican voters here in the Palmetto state in a way that advertising cannot.

And Romney has, against his wishes, been forced by Gingrich's rise to agree to two more debates between now and Florida's primary. The first is Monday, giving Gingrich an immediate opportunity to score points against Romney in front of Florida Republican voters.

Romney previewed the argument he'll make against Gingrich in Florida in his concession speech. In short, he said that Gingrich is like Obama.

"Our party can't be led to victory by someone who also has never run a business or a state," Romney said, comparing Gingrich's lack of private sector and executive experience to Obama's, prior to becoming president.

Romney aligned himself with "those who believe in prosperity," and indicated that Gingrich was on the side of "those who believe in government."

Romney's nightmare scenario is one in which Gingrich wins Florida and becomes the frontrunner. Yet even if that were to happen, the month of February will present new challenges for Gingrich. The Romney campaign hopes February will be a Newt-grinder.

Four states will hold caucuses in early February: Nevada on Feb. 4, Colorado and Minnesota on Feb. 7, and Maine's Republicans will hold caucuses for a week with the results being announced on Feb. 11. Caucus states require higher levels of organization to win, and only Romney and Rep. Paul (R-Texas) have done so in those states. Other than Missouri's non-binding Feb. 7 primary, there is nothing else until Feb. 28, when Arizona and Michigan have their primaries.

Washington caucuses on March 3. And then 11 states will hold primaries or caucuses on Super Tuesday, March 6.

During that roughly three-week stretch of dead time, the Romney campaign is confident that it can undermine Gingrich and persuade Republicans that the volatile politician is what they have argued he is this week: an unreliable and unpredictable human being who cannot be trusted with the presidency. They fully expect Gingrich to help them make that case, by making comments or behaving in a way that demonstrates his lack of discipline.

"He is a ticking time bomb," said Henry Barbour, a top Republican party fundraiser from Mississippi who moved his support to Romney from Texas Gov. Rick Perry after Perry dropped out on Thursday.

"He won't last. He's great for a cable news show, but when does he blow up?" Barbour told HuffPost. "Romney has the plan, infrastructure and resources to win a quick or protracted campaign. Gingrich and Santorum will have a very hard time managing this as the pace quickens beyond their ability to execute in all the places they need to campaign. It's a brutal process."

But in politics, momentum can be an overwhelming force, and for now, Gingrich has plenty of it.

Updated second paragraph on Jan. 22 at 10:40 a.m. with further details on election results.