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.

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 would 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.

Newt 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 late Saturday found the former House speaker leading the GOP field with 25 percent support, ahead of Paul at 18 percent and Romney at 16.