The day after sparring heatedly in a televised debate, Republican candidates vying for the 2012 presidential nomination popped from breakfast gatherings to campaign rallies to the celebrated Iowa State Fair — a must-do for presidential hopefuls who share the spotlight with a cow sculpted from butter and deep-fried candy bars.

The new urgency among the candidates had everything to do with Saturday’s Ames Straw Poll, an early test of organizational strength that could hasten departures for those who don’t perform well. In particular, former Minnesota governor Tim Pawlenty was in overdrive to draw supporters to the event and turn around a campaign that has struggled to raise money and gain traction in the polls.

By all accounts, the outcome of the straw poll remained unusually up for grabs in an uncertain and still-growing field of candidates, with Pawlenty, fellow Minnesotan Rep. Michele Bachmann and Texas Rep. Ron Paul all in position to perform well after weeks of building support across the state.

Just what the outcome will mean is equally uncertain, however, given the list of candidates not competing in it. Texas Gov. Rick Perry, who is expected to announce his candidacy Saturday morning, and former Alaska governor Sarah Palin, who visited the state fair Friday, will not be on the straw poll ballot even though both could soon be in the race.

Similarly, former Massachusetts governor Mitt Romney and former Utah governor Jon Huntsman Jr. will not participate in the poll, with both heading to events in New Hampshire.

“It’s probably as unpredictable a straw poll as we have had,” said Matt Strawn, chairman of the Iowa Republican Party. “I think some of that goes to the fluidity of the race and the late-developing nature and the notion that most Iowa caucus-goers are still at the dating phase of the caucus process. They perhaps haven’t married the candidate they will see all the way through the caucus.”

Pawlenty took to the Des Moines Register’s “soapbox” at the fair, as did Paul and Bachmann — his two main rivals in the straw poll. Like the rest of the Republican field, Pawlenty spent most of his time criticizing the man he hopes to challenge next year, President Obama.

“Tell Barack Obama he has had his chance and it isn’t working,” Pawlenty said.

A win for Pawlenty could give him the momentum he needs, while a loss, depending on its severity, could doom his ability to draw crucial donors heading into the fall. Bachmann hopes to show that she can sustain her catapult to the top of the standings in Iowa since declaring her candidacy in June. Paul is hoping that a strong showing will grow his base beyond a narrow band of Republicans who are attracted to his libertarian and isolationist views.

For candidates lower in the standings, such as former Pennsylvania senator Rick Santorum and businessman Herman Cain, a good showing could provide a much-needed boost, and a poor one could doom their chances.

Amid the livestock shows, carnival rides and fried delicacies of the state fair, Palin attracted the most attention with a midday stroll through the exhibits and a private lunch with her husband, Todd. Palin said she has made no decision on running but doesn’t want to keep her supporters waiting “in perpetuity.”

Bachmann, meanwhile, rolled her road show across Iowa on Friday, deploying crisp one-liners and savvy stagecraft to rally supporters to the straw poll.

With Elvis blaring through a parking lot at her final rally of the day, in Ames, the Minnesota congresswoman bounded out of her campaign bus, grabbed her husband, Marcus, and began dancing the jitterbug before unleashing a flurry of attacks on Obama.

“Iowa is the place that launched Barack Obama, and Iowa will be the place that gets to put that presidency to an end,” she told a cheering crowd of about 150 people at Iowa State University, where the straw poll will be held Saturday.

When she finished her remarks, she wrapped up by tossing popcorn balls into the crowd.

At the straw poll, passersby can walk through a series of tents that are positioned and sized according to how much the candidates paid. The campaigns ply supporters with free tickets, free shuttle rides and free barbecue — hopeful that their efforts will pay off with the few thousand votes it will take to win the contest.

For weeks, Pawlenty has focused on winning the straw poll, crisscrossing Iowa with scores of stops and collecting hundreds of names, numbers and e-mail addresses to draw supporters to Ames. Even on Thursday, in the moments before Fox News started its broadcast of the debate, a dozen or so volunteers at his Iowa headquarters in Urbandale were working the phones.

“I can give you so many options!” one volunteer said enthusiastically into his cellphone, pacing the carpeted office. “We have a bus leaving Wal-Mart. We have a shuttle running all day long between Ankeny and Ames. It’s going to start at 9 o’clock and run all day back and forth. So you can park anytime at the middle school and then you can get on the shuttle and come back when you want and you’re done. Is that something you’d like to do?”

Pawlenty’s organizational firepower goes up against the more dramatic energy that both Bachmann and Paul have drawn from supporters.

Paul paid $31,000 for the prime tent spot just outside the Hilton Coliseum where voting will take place. And to encourage voter loyalty, Paul’s campaign is helping to pay the $30 straw poll ticket price. Other campaigns are paying the full freight, but the idea is that a voter who chips in $10 is more likely to show up and vote for Paul.

“We’ve picked up a number of volunteers because a lot more people know him and support him,” said Gary Howard, a spokesman for Paul. “Last time around, there was no tea party. Now there is.”

Staff writers Chris Cillizza and Philip Rucker contributed to this report.