WASHINGTON – A day after Herman Cain shuttered his Republican candidacy for president, struggling GOP hopefuls looked to pick up the fallen candidate’s tea party following and upset a primary dynamic that has pushed Mitt Romney and Newt Gingrich to the forefront.

Reps. Ron Paul of Texas and Michele Bachmann of Minnesota said Sunday they expected Cain supporters would fall in line behind them because of their messages on limited government, despite their low standing in the polls. Meanwhile, last-place rival Rick Santorum predicted he now had a good chance of winning the Iowa caucus.

While such brazen predictions are likely overstated, the 11th-hour press comes at a crucial time and could upset an already volatile race for the GOP endorsement.

A month before the first vote is cast in the Iowa caucus and five weeks before the New Hampshire primary, most GOP candidates were looking to a week of heavy campaigning in Iowa ahead of the next debate, scheduled for Saturday. The stakes are possibly the highest for Mitt Romney, who could be hurt the worst if Cain supporters rally behind Gingrich.

“A lot of Herman Cain supporters have been calling our office and they’ve been coming over to our side,” Bachmann said. “They saw Herman Cain as an outsider, and I think they see that my voice would be the one that would be most reflective of his.”

Likewise, Paul said he was optimistic that Cain’s departure would reinvigorate his campaign.

“We’re paying a lot of attention to that, because obviously they’re going to go somewhere in the next week or so,” Paul said of Cain’s supporters.

Santorum predicted that his campaign will pick up steam in coming days.

“We have a very strong, consistent conservative message that matches up better with Iowans than anybody else. And we think we’re going to surprise a lot of people,” he said.

Once surging in the polls, Cain dropped out of the race Saturday after battling allegations of sexual harassment and a claim that he had a 13-year extramarital affair. The Georgia businessman has denied the accusations.

Gingrich, the former House speaker from Georgia, has so far been the biggest beneficiary of Cain’s slide. A Des Moines Register poll conducted Nov. 27-30 and released Saturday found Gingrich leading the GOP field with 25 percent support, ahead of Paul at 18 percent and Romney at 16.

A separate NBC News/Marist poll showed Gingrich beating Romney, 26 percent to 18 percent, among Republican caucus attendees in Iowa.

Gingrich also is enjoying national popularity that could give him the momentum he needs to overcome deficiencies in the organization of his campaign. At the same time, Gingrich says he knows his surge in the polls could disappear if his opponents stage a comeback.

“I’m not going to say that any of my friends can’t suddenly surprise us,” Gingrich said at a recent town hall meeting in New York sponsored by tea party supporters.

Meanwhile, Romney is running strong in New Hampshire, which holds the nation’s first primary Jan. 10. Romney is also seen by most conservatives at this point as having the greatest chance of defeating President Obama next year.

But Romney continues to be viewed with suspicion by many conservatives who say he has changed his stance on critical issues such as abortion and health care. Santorum acknowledged Sunday that Romney has embraced more conservative positions on issues.

“The question is, you know, what’s the sincerity of the move and whether he can be trusted,” Santorum said.

Bachmann said it was too soon to declare anyone a true front-runner because the dynamic in the race was constantly changing.

“We’ve got 30 days,” she said. “That’s an eternity in this race.”