In the end, Bachmann won the 2011 Ames Straw Poll, a political carnival on the campus of Iowa State University that has become a media-swarmed early test of presidential candidates' strength.
Paul, a libertarian with a devoted following, finished a close second, followed by former Minnesota Gov. Tim Pawlenty, who had counted on the event to get traction. Santorum finished fourth.
"This was a wonderful down-payment on taking the country back," Bachmann, also of Minnesota, told ecstatic supporters as she stood in front of her campaign bus.
A bigger challenge looms for the first woman to win the straw poll, with 28.6 percent of the nearly 17,000 votes cast. Texas Gov. Rick Perry announced his candidacy Saturday in South Carolina, saying it was time to "get America working again," as voting was under way here. He appeals to the same combination of tea party activists and social conservatives who constitute Bachmann's base, and Texas has had the fastest rate of job growth in the country the last several years.
Bachmann could find herself edged out for the attention of the media, donors, and GOP activists pursuing the Next Big Thing.
Perry drew 718 votes in the straw poll as a write-in, outdrawing national frontrunner Mitt Romney, whose name was on the ballot but who did not mount a campaign for the poll.
Pawlenty, meanwhile, had hoped to make more progress in Iowa, where he'd spent the bulk of his recent campaigning time.
"Paul had the strong second-place finish that Pawlenty needed," said Dennis Goldford, a political science professor at Drake University in Des Moines. "That's a major stab in the gut. Is it mortal?" The answer, he said, will depend on whether Pawlenty can raise money over the next month.
Santorum was encouraged by his finish, after spending 18 days in the state with his family, hitting 68 Iowa counties and concentrating on small towns that don't often see candidates.
"I feel great," Santorum said. "The candidates who finished above us each spent more than $1 million and had big operations on the ground.. . . David went in with Goliath and didn't do too bad."
He predicted that he would age "like a fine wine" compared with the candidates who finished ahead of him.
The straw poll is a strange beast, founded to raise money for the Iowa Republican Party. Vote-buying is encouraged. Candidates pay tens of thousands of dollars for the tent space on the grounds, and buy $30 tickets for their supporters to attend and vote. The campaigns also provide bus rides from towns throughout the state; as people listened to the entertainment at candidates' tents, volunteers reminded them to vote and gave the departure times for the various bus routes.
Gov. Terry Branstad said the straw poll had helped finance the party's successful state legislative races in the past. "This is about the state Senate" in 2012, he said. Democrats now control the Iowa Senate, 26-24.
Agreeing that all politics is local, Iowa Democratic Chairwoman Sue Dvorsky said her party's effort to hold onto the Senate - the GOP has the House and the governor's office - would boost efforts to organize for President Obama in the general election.
Democratic activists want to avoid what happened in nearby Wisconsin, where GOP Gov. Scott Walker, with his party in control of the legislature, stripped collective-bargaining rights from public workers.
"This is not a matter of getting the old band together," Dvorsky said. "Iowa's Democratic base is ready to go. They're nervous."
Laurie Adams voted for Pawlenty, her hand marked with black Sharpie to indicate that her ID had been checked and that she had cast a ballot.
"He's the most electable," said Adams, who works for a campus ministry at Iowa State. "Governors tend to have a little more credibility than congressmen. I loved what Michele Bachmann had to say, though. It's unfortunate that they've been nipping at each other's heels."
Dennis Bahls was not going to attend the straw poll, but he decided to catch a ride with a friend who had turned him on to Paul.
"Ron Paul is a constitutional person," Bahls, of Elkader, a town in far northeast Iowa. "I agree with him that we have too many involvements with other countries. We need to take care of home first. There's so much government debt, I'm really afraid for my kids and grandkids."
John Harvey, 76, a retired teacher who advises homeschoolers, said he supported Bachmann because she's a "great grassroots lady with her head on straight." He added that she is "not afraid and doesn't budge."
Don Burtmier said he was most impressed by Bachmann's open evangelical Christian faith.
"She stands for the God who started this country, and that's what we need," said Burtmier, 64, of Des Moines. "We've lost God, and that's why we're going down.. . .She'll push for laws based on godly principles."
Already, Bachmann is moving to take on the newest Republican contender. On Sunday, she'll appear on five major morning news-talk shows, then make a dinner speech in her native Waterloo - the same dinner at which Perry will make his first Iowa campaign visit.
Contact politics writer Thomas Fitzgerald at 215-854-2718, email@example.com, or @tomfitzgerald on Twitter. Read his blog, "The Big Tent," at www.philly.com/BigTent