DES MOINES - In her first foray to Iowa as a potential presidential candidate, Rep. Michele Bachmann, R-Minn., painted an unabashed portrait of America under siege.

"Will America endure? And I don't say this melodramatically. ... Tonight, I think the answer is in grave doubt," Bachmann told hundreds at an Iowans for Tax Relief event on Friday night. "There is doubt in the minds of Americans that we will continue as this great, exceptional nation."

Whether the Stillwater congresswoman will promote that message as a presidential candidate is unclear. But just three weeks after she let it be known that she might be interested in the top spot, she has ignited a fire.

Throughout the crowd, Iowans said they came to see Bachmann, whom many had already seen on TV or read about on the Web, for themselves. But they already had their impressions -- "inspirational," one said. "Dynamic," said another. "She's a little fireball," said a third.

"I have respect for anyone who is willing to stand up and speak for what they believe," said Roger Rowland of West Des Moines. But he is far from picking a favorite in the 2012 race.

Nearly 50 journalists showed up for her speech in the early presidential caucus state, where she also was inundated with face-time requests from politicos.

The Iowa speech was one of a flurry of high-profile events for the three-term congresswoman.

On Friday, she met with Iowa Gov. Terry Branstad, Iowa Republican Party Chairman Matthew Strawn and lawmakers in a clear signal that she's ramping up efforts there. The speech to the tax relief crowd was attended by many potential caucus-goers, as well as Branstad, his wife and the Iowa lieutenant governor.

On Saturday, she will speak at an anti-abortion rally at Minnesota's State Capitol. On Monday, she'll speak at the national Right-to-Life March in Washington, D.C. Later that day she'll host Supreme Court Justice Antonin Scalia at a Constitution class she organized in Washington, and that evening she'll deliver the keynote speech at the March for Life Rose Dinner. She will cap the stretch on Tuesday night with her own State of the Union rebuttal, live-streamed by the Tea Party Express.

Decrying 'bondage of debt'

While the spotlight shines more brightly on Bachmann these days, she has been a politician to watch since she burst onto the Minnesota scene nearly 20 years ago.

Democrats deride her as a factually challenged, over-the-top, self-serving firebrand. But Bachmann has shown she is not to be taken lightly.

"She would be a stick of dynamite" if she ran, University of Virginia political science Prof. Larry Sabato wrote in describing the dramatic impact she could have.

Bachmann knows how to work a crowd, raise funds and organize grass-roots conservatives like few others. In Minnesota, her organization has been particularly effective among the evangelical right -- a possibly potent advantage among the activist-dominated, churchgoing Iowa caucus crowd.

"In the Republican Party in Iowa, they are a substantial vote," said Cary Covington, a political science professor at the University of Iowa. Connecting with Christian evangelicals helped 2008 GOP presidential candidate Mike Huckabee win in Iowa.

Steve Scheffler, Iowa Faith & Freedom Coalition President and a Republican National Committee member, said Bachmann has his respect for her "ability to articulate the issues" and not flinch when criticized. He has invited her -- and a host of other potential candidates, including former Minnesota Gov. Tim Pawlenty -- to a March 7 Faith & Freedom forum.

Bachmann also brings a strong cadre of followers from the Tea Party. "She is one of the top leaders in the movement," said Brian Darling, director of government relations for the Heritage Foundation.

On Friday, she largely avoided the specific political statements that have won her attention. Instead, she stayed in storyteller mode, winding a tale of America, her family's immigration and threats she sees. It was not a speech that packed applause lines; the audience was hushed, listening.

But she did throw out some strong opinions, saying that the federal government owns half of the country's mortgages, that the Medicare trust fund will go "flat broke" in six years and that Barack Obama has accumulated more debt in one year than all past presidents combined. She also likened the "bondage of debt" and the "bondage of decline" to slavery.

Bachmann vs. Pawlenty

Iowa GOP Chairman Strawn said Pawlenty has been well received in Iowa. But, he said, Republican activists also have "a great interest to learn a little bit more about Congresswoman Bachmann."

Pawlenty has meticulously taken steps to set up a national fundraising committee, show up at conservative gatherings and write the obligatory bio book. He ventures often to Iowa and has already spoken to the antitax group that Bachmann addressed on Friday.

"For somebody like me, you have to do very well, win or do very well, in Iowa," he said on Fox News last weekend. He will stop in the early primary state of New Hampshire on Monday and return to Iowa at month's end as part of his book tour.

While the critique of Pawlenty is that he is likable but not exciting, Bachmann generates excitement from those who loathe and love her.

Bachmann has not done as much work or made her interest in the presidency as clear as Pawlenty has. But on Friday she offered a profile for the next president -- "a bold, strong, constitutional conservative" -- that sounded a lot like her.

Bachmann, who frequently reminded Iowans that she grew up in Iowa, already has the presidential candidate flirtation down. She told the crowd that she wouldn't keep them in suspense, that she would announce ... "It's really good to be home." The pre-declaration joke got a good laugh.

Both Bachmann and Pawlenty will return to Iowa to speak as part of a "presidential lecture series" organized by the Family Leader group in the coming months.

Staff writer Jeremy Herb contributed to this report.