INDEPENDENCE, Iowa — Republican presidential hopeful Newt Gingrich all but conceded defeat on Monday in Iowa, a day before the state becomes the first state to weigh in on the White House race.

"I don't think I'm going to win," Gingrich said early in the day.

By nightfall, he was offering a more upbeat assessment after one of his precinct captains complained during a telephone town hall that he was dispirited by the prediction.

"We may pull off one of the great upsets in the history of the Iowa caucuses," Gingrich said in Davenport, urging supporters to help him.

The former House speaker, who tumbled from front-runner to also-ran in recent weeks, was working to rebound after polls showed him sliding in recent days.

Even as he raced through a final blitz of appearances in eastern Iowa on Monday, Gingrich said he was warming up a more potent counterpunch for New Hampshire and South Carolina, the next stops for the Republican presidential contest.

Gingrich said he should have responded more forcefully to negative TV ads that he says distorted his record. And he pledged to draw a sharper contrast with his rivals, notably Mitt Romney, in the days to come.

Just a few weeks ago, Gingrich sat atop the polls in Iowa. Now, he says he will take solace in surviving after being battered by a wave of brutal attack ads.

"Whatever I do tomorrow night will be a victory because I am still standing," Gingrich said in Independence, one of four campaign stops he made on the eve of Iowa's first-in-the-nation caucuses.

Gingrich's pitch to voters is framed on experience, even as he has simultaneously tried to claim the mantle of Washington outsider.

"I'm the only candidate who has an actual track record — twice with (Ronald) Reagan and then as speaker — of actually changing Washington," he said. "Everybody else would be an amateur in the Obama tradition who would not know what they are doing or how to do it if they won."

Cribbing from Reagan's playbook, Gingrich has been emphasizing lower taxes, fewer regulations and an American energy policy.

After being hammered by millions of dollars in negative ads, Gingrich also has a new rival: independent political action committees spending big money on attack ads. The tirade against the "junk on TV" regularly earns Gingrich sustained applause on the campaign trail.

While Gingrich has not run negative ads — and has promised not to — he hasn't been shy about waging a ground war. On Sunday, he said Romney, a millionaire many times over, "would buy the election if he could."

Supporters who flocked to his crowded campaign stops said they were attracted to Gingrich's vast constellation of ideas.

"I think his baggage actually makes him a better candidate," Tim Burrack, of Arlington, said Monday. "If you never try anything you never make mistakes."

Gingrich was set to fly to New Hampshire Tuesday night after the results in Iowa come in. But, already, he has his sights set on South Carolina, the first Southern primary, on Jan. 21.

Gingrich is quick to note that no GOP candidate has won the party's nomination without claiming South Carolina. He's hoping his Southern roots as a congressman from neighboring Georgia will translate into favorite-son status.

"I think New Hampshire is a good place to start the debate for South Carolina," Gingrich said.