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Rick Santorum's banner election performance Tuesday night has exposed the risk in Newt Gingrich's plan to wait for the primary battle to come to him, as Santorum claims the momentum charging into the contests Gingrich needs for another surge.

"We felt it coming," Santorum told Fox News on Wednesday. "We've got a campaign that can attract folks from all across this country."

The Republican presidential candidate, a former Pennsylvania senator, later said his campaign has raised more than $400,000 in the last two days.

Santorum's three-for-three sweep Tuesday night puts the pressure on Gingrich to reassert his claim as the "conservative" alternative to Mitt Romney. Gingrich, since losing Florida in late January, has touted a strategy that hinges largely on the March 6 Super Tuesday contests, upcoming primaries in Southern states and the Texas primary in April -- when 155 delegates are at stake.

But Santorum's showing in Minnesota, Colorado and Missouri throws a wrench into those plans and could compel Gingrich to tweak his approach. The former House speaker does not want to see Santorum seize the anti-Romney mantle on the cusp of Super Tuesday, when 10 states hold contests.

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"That's always the big danger when you decide to sort of skip some states," Democratic strategist Joe Trippi said. "That's an opening."

Trippi said the ideal outcome for Gingrich on Tuesday would have been a split decision, with each of the three states going for one of his opponents, if not for him. Instead, Santorum won all three -- two by a decisive double-digit percentage margin.

"There's no way to un-ring that bell. Santorum is a much stronger force today than he was the day before last night," Trippi said.

Though there are still a few more contests before Super Tuesday -- in Maine, Michigan, Arizona and Washington -- Gingrich so far seems to be sticking to the plan. He campaigned Wednesday in Ohio, one of the big Super Tuesday prizes. Trippi said Gingrich would be best served to hunker down in a few of those states and absolutely commit his campaign to winning them.

Among those states would be Georgia, which the Gingrich campaign announced Wednesday the candidate would be visiting in a two-day swing next week. Gingrich represented Georgia in Congress and has the support of Georgia Gov. Nathan Deal.

Republican strategist Ed Rollins said that Tuesday was a bad night for Gingrich but added that the former House speaker is by no means out of the race.

The Gingrich campaign has touted its finances and says it raised about $2 million in Nevada, despite losing there to Romney last weekend. Gingrich also has fundraisers planned for California next week.

Gingrich, at a news conference in Nevada on the night of the caucuses last weekend, was unequivocal about his intent to battle Romney to the end for the nomination.

Gingrich said the notion of him withdrawing is the "greatest fantasy" of the Romney campaign.

But while Gingrich stays focused on Super Tuesday, Santorum is ceding no state to Romney.

On MSNBC, Santorum said he'd debate Romney in Arizona, the home of a sizable Mormon population and a key patron, Sen. John McCain, the GOP presidential candidate in 2008. Also on Santorum's travel schedule: Michigan, where Romney's father was governor.

A subdued Romney congratulated Santorum and said he'd press on.

"This was a good night for Rick Santorum," Romney told supporters in Denver on Tuesday. He offered a bit of forced optimism: "We'll keep on campaigning down the road, but I expect to become our nominee with your help."

The Associated Press contributed to this report.