(Corrects size of poll lead in paragraph 14, changes wording of 2nd paragraph, bullet point)
* Gingrich still on top but some polls show tight race
* Georgia has most delegates of Super Tuesday
* Was top of pack only a month ago
By Deborah Charles
ATLANTA, Feb 25 (Reuters) - Only a month ago, Newt Gingrich was atop the Republican presidential race. Now he is in a fight for a win even in his home state of Georgia as his campaign stakes its future on the Super Tuesday primaries.
Two polls out of three in recent days show Gingrich running a close race in the state with either Mitt Romney or Rick Santorum, who is making inroads with the large number of evangelical Republicans in Georgia. But he will take hope that one of those polls gave him a healthy lead of 13 percentage points over Santorum and 19 over Romney.
A loss in Georgia, the biggest of the 10 states holding contests on Super Tuesday on March 6, would deal a severe blow to any chance Gingrich has of winning the Republican nomination.
"It's incredibly important to Gingrich to win Georgia if he hopes to launch his 'Southern strategy,'" said Merle Black, professor of politics at Emory University in Atlanta.
Gingrich has put Georgia at the heart of his strategy to win southern states and come back from a dramatic fall since his big win in the South Carolina primary on Jan. 21. The former House of Representatives speaker went on to lose badly to Romney in Florida and suffered from the rise of Santorum as the more conservative choice among Republicans.
Gingrich decided to forgo campaigning heavily for Tuesday's primaries in Arizona and Michigan, the next states to vote in the Republican nominating process to decide who will face President Barack Obama in November's presidential election.
He launches a two-day bus tour of Georgia on Tuesday to try to shore up support after Santorum made waves in the state last Sunday with a visit to a megachurch where 3,000 worshippers gave him a standing ovation.
Polls show Santorum and Gingrich are vying for support of voters who identify themselves as "somewhat conservative" or "very conservative," Merle said.
Kathy Hildebrand, the Georgia field director for Santorum, said the church event surpassed expectations and generated hundreds of new volunteers.
"Three weeks ago there was no structure for a campaign for Santorum in Georgia," said Hildebrand.
A poll early this week by Insider Advantage set off alarm bells for Gingrich, who was at 26 percent support, followed by Romney 2 percentage points behind and Santorum another point down. That was a dramatic change from earlier polls that gave Gingrich a double-digit lead.
"It is possible that Gingrich could lose his own congressional district," said Mark Rountree, a Republican political consultant and pollster. "He has to win his congressional district and the state."
Romney, a former Massachusetts governor, is strong in Atlanta's northern suburbs, part of the congressional district that Gingrich represented for around 20 years.
But Gingrich can take hope from a Landmark-Rosetta Stone poll done on Thursday that showed him with a 13-point lead in Georgia over second-placed Santorum. A Rasmussen poll released the same day had Gingrich in the lead over Santorum by 5 percentage points.
Often criticized for being irascible, the former history professor has toned down and, when asked in a CNN debate to chose one word to describe himself, chose "cheerful."
Gingrich is in a trap of his own making after telling Fox News before the latest polls were released that if any of the candidates lost their home state they would have "very, very badly weakened candidacies." Romney is struggling to stay ahead of Santorum in a tight race in Michigan, where he was born and his father served as governor.
Many voters in Gringrich's own home state may be waiting to see who wins in Michigan and Arizona before committing to the former speaker.
"I like him, but he's not a front-runner," said one woman in northern Atlanta, who refused to give her name. "So I'll vote for Romney or Santorum, I'm just not sure which yet."
SUPER PAC ATTACK
Hammering on a message he hoped would help him muscle back into the race, Gingrich has been the most vocal of the Republican candidates on a key voter concern: gasoline prices that have soared to almost $4 a gallon.
"I'm pretty sure I can get you between $2 and $2.50 through the free market without being dishonest," he told voters in Washington state. President Barack Obama on Friday described Republican promises of lower gas prices as "phony."
Much of Gingrich's fall from the top of the pack was due to negative TV and online ads sponsored by the Restore Our Future "Super PAC," or political action committee, that supports Romney.
Ads portraying Gingrich as a Washington insider and supporter of big government helped Romney bring him down in the Florida primary.
While attacking Santorum in other states, the Romney Super PAC is sticking with an anti-Gingrich ad in Georgia and has bought some $1.1 million worth of air time through Super Tuesday. The group has also reported spending around $82,000 in the state on Internet advertising against Gingrich.
Matt Towery, a former Gingrich campaign adviser from the 1990s but no longer affiliated with him, said Gingrich needed to counter negative ads against him by airing his own in Georgia.
"The barrage of negative ads that Gingrich is sustaining in Georgia is having an effect on his otherwise natural likelihood to win the state," said Towery.
"I think there will be a natural settling point but it's going to be problematic for him if he doesn't get on the air."
One hope for Gingrich to win in Georgia is that Santorum fails to take Michigan, giving the former speaker a chance at rebounding as the conservative alternative to Romney.
"It's possible Newt could get another look as the anti-Romney. I think there are probably some more twists and turns here," said Republican strategist Matt Mackowiak. (Additional reporting by Andy Sullivan and Alina Selyukh; Editing by Alistair Bell and Eric Walsh)