Presidential hopefuls Michele Bachmann and Tim Pawlenty on Monday blamed President Barack Obama's spending policies for the downgrade in the nation's credit rating, seeking political gain days before a test vote by Iowa Republicans.

"We were able to get through the Great Depression and not see a credit downgrade. Only under this president have we seen a credit downgrade," Bachmann, a Minnesota congresswoman, said at an appearance here.

In Ames, Pawlenty, a former Minnesota governor, called the decision by Standard and Poor's to downgrade the U.S. credit rating "just one of many indications that our federal government is out of control, our economy is stumbling and the president's direction has been ineffective and wrong."

Both candidates were packing their daily campaign schedules with multiple events ahead of Saturday's Iowa straw poll, an important test of organizational strength as well as popularity. The stakes are high for the rivals from Minnesota; Bachmann hopes to keep her momentum going with a strong showing while a struggling Pawlenty is looking for a much-needed boost

"One has to beat expectations and one has to live up to them," said veteran GOP strategist Bob Haus, who is unaligned in the race.

Other candidates, to be sure, are on the ballot for the nonbinding vote in Ames. But some are competing more heavily than others.

Former Massachusetts Gov. Mitt Romney, the front-runner so far, along with former Utah Gov. Jon Huntsman and former House Speaker Newt Gingrich are bypassing the event even though they will be on the ballot.

Bachmann, a tea party favorite who has been running strong in polls since getting in the race earlier this summer, and Pawlenty, who has been building a campaign for more than a year but remains low in polls, arguably have the most on the line. They are seeking to reach as many GOP activists as possible over the next few days.

While the two largely focused their fire on Obama, Bachmann said her fight against the debt ceiling was unique; the congresswoman reminded Iowans that she voted against raising the debt ceiling.

"What sets me apart from the other candidates is that I have stood up time and time again," Bachmann said. She warned of more trouble ahead if the nation doesn't deal with its debt. "There's a one in three chance we could be downgraded again."

She added, "Clearly we can't afford the government that we have."

Pawlenty echoed that theme while in Ames, saying the decision by the rating agency makes it clear that the federal government is out of control and needs to be cut back. He also faulted Obama, saying: "These problems have been percolating for a lot of years _ both parties have to take some blame _ but it's also true that President Obama has made them exponentially worse."

Pawlenty has campaigned tirelessly in the state, only to see his polling numbers stuck in single digits. He argues that he's spent time patiently building a campaign organization, but he'll have to demonstrate that organization's ability to turn out backers on Saturday or many will see his campaign in trouble.

"Our goal is to move from the back of the pack toward the front of the pack and I'm confident we will do so as my message of cutting government and growing jobs and doing things like appointing conservative justices gets out," he said. "I don't think we need to win it, but I think need to show some good progress and I'm confident we will."

Bachmann's pitch to backers was more direct and upbeat _ she promoted her campaign's entertainment plans for Saturday's event _ as she looked to keep momentum on her side.

"I will guarantee you (that) you will have the time of your life," said Bachmann. "We're going to feed you and we're going to entertain you with Randy Travis. Sign up right here, we need your vote."