Full of confidence and bombast, Newt Gingrich last week began an eight-day bus tour across Iowa, figuring that the picnic basket of “positive” ideas he has served crowds for months would be enough to stem his downward slide.

But that was before polls showed him dropping into fourth place and his message seeming to fall flat. It was before his opponents were done pummeling him with millions in attack ads. Then there were the tears when he talked about his mother and, finally, a vicious flu that left his eyes watery, his speech sluggish and his campaign fighting the perception that the candidate was limping to a disappointing Iowa finish.

Gingrich conceded as much at a farm exhibit here Monday morning when he told reporters, “I don’t think I’m going to win.” It was a bitter acknowledgment for a man who just a month ago boldly predicted that he would be the Republican nominee, with an assurance that left little room for doubt. Gingrich hasn’t given up on that just yet; he has made clear that he’s prepping for a serious counterattack against Mitt Romney, whose supporters’ ads have badly damaged the former House speaker’s chances.

But after surging to the top of the field weeks ago, the Gingrich of the past several days has come to understand that he was wrong about a few things, namely that there is only one story to Newt Gingrich. In fact, the other story took hold, too, leaving him open to attack and struggling to reposition himself.

Since he rolled into Iowa last week, the lurching has continued. In a basement community room at Mabe’s Pizza in Decorah, the crowd overflowed up the stairs into the main dining room, where families gathered for dinner could hear the approving cheers and applause through the floor.

The appeal? Gingrich’s brimming confidence and fluency on the issues. He is a conservative in the mold of Ronald Reagan and Barry Goldwater. He led the charge against Bill Clinton in the 1990s for lower taxes, smaller government and welfare reform. As one woman put it at a question-and-answer session in Ottumwa: “Your ideas are spectacular. Your brain is just inspiring.”

The story was similar at the Chocolate Season in Algona, where fans spilled out onto the chilly sidewalk. And Gingrich attracted more than 70,000 callers to a series of telephone town halls since Christmas. His spokesman, R.C. Hammond, became so well versed that he began cuing up three cellphones with different carriers so Gingrich could stay connected even when the call got dropped.

But at the Dubuque Golf and Country Club and the Heartland Acres Agribition Center in Walford, crowds listened politely but exhibited little enthusiasm. When asked if they’d seen any of the ads attacking Gingrich, the near-universal answer: “Of course!”

And although all the crowds applauded when Gingrich condemned the negative ads, it was clear that the refrain — that Gingrich is a Washington insider; that he was paid $1.6 million by federally backed mortgage giant Freddie Mac; that he was sanctioned for ethics violations when he was speaker — had taken a toll.

Retiree Ralph Davey, 60, who is undecided and came to hear Gingrich speak in Mason City, said: “I like Newt. He was way down in the polls. He bounced back and showed some resilience. And I like his conservative values.” Yet Davey still has reservations, he said, because of Gingrich’s baggage.

With Gingrich, the point had sunk in by week’s end. “I wouldn’t vote for the guy they’re describing!” he began quipping. He also began figuring out how to fight back. On his bus between stops in Mason City and Algona, Gingrich recorded a phone message to go to 100,000 homes denying a charge that he is not a strong supporter of gun rights.

And his barbs toward Romney have grown sharper by the day. “Somebody who will lie to you to get to be president will lie to you when they are president,” he said Sunday.

He is also trying to change the narrative. “Whatever I do tomorrow night will be a victory, because I’m still standing,” he told reporters. He is looking beyond Iowa, he said, to New Hampshire, South Carolina and Florida.

Gingrich has also altered his directive to stay positive. “No more” was his message on Monday, along with a preview of what’s to come — a brutal comparison of his conservative record with Romney’s history as a “Massachusetts moderate” who refused to sign the Contract With America and supported abortion rights.

“This is the first few minutes of the Super Bowl,” Gingrich said. “I think it’s been a good three minutes for us. I think we’ve begun to lay out the themes that will work. I think we’ve seen Romney do his most intense negatives, and we now have had time to think through how to respond.”

Whether that response will work is a question that will have to wait until after Iowa.