Ames, Iowa ? The 2012 Republican presidential race lurched into a new phase Saturday as Iowans weighed in for the first time on their expanding field of presidential hopefuls, picking Michele Bachmann as their top choice for the GOP nomination. Halfway across the country latecomer Texas Gov. Rick Perry formally entered the race, declaring: “America is not broken. Washington, D.C., is broken.”

Together, the events were certain to reshuffle the race to face President Barack Obama. Exactly how was anybody’s guess, as the candidates sought an early validation that they have widespread appeal, with those further behind in the pack hoping to gain momentum and avoid increased questions over their campaign viability.

A slew of Republicans are seeking the chance to challenge Obama next fall for the leadership of a country facing a recent downgrade in its credit rating, high unemployment and Wall Street tumult. And, from Iowa to South Carolina on Saturday, several of those candidates used their perches before GOP activists in two critical early voting states to castigate the Democratic incumbent and offer themselves as the answer to an ailing America.

“We are going to make Barack Obama a one-term president,” Bachmann declared to cheers on the campus of Iowa State University during a daylong political festival. A few hours later, she learned she won the Iowa straw poll and said: “This is the very first step toward taking back the White House!”

Bachmann, the tea party favorite with a following among evangelicals who make up the GOP base in Iowa and elsewhere, got more than 28 percent of the 17,000 votes cast in the nonbinding exercise. It provides clues about each candidate’s level of support and campaign organization five months before the Iowa caucuses kick off the Republican primary season.

Texas Rep. Ron Paul, who has support among libertarian-leaning voters, came in a close second. Former Minnesota Gov. Tim Pawlenty was looking for a strong showing to boost his struggling campaign, but fared a distant third, raising questions about the future of his candidacy.

“We have a lot more work to do,” Pawlenty said, suggesting he wasn’t dropping out despite the disappointing finish. “We are just beginning.”

Former Pennsylvania Sen. Rick Santorum was fourth, followed by businessman Herman Cain. Perry, who wasn’t on the ballot but was written in by supporters, came in sixth, just ahead of GOP front-runner Mitt Romney, the former Massachusetts governor who didn’t compete in the straw poll. Also on the ballot but barely registering support: former Utah Gov. Jon Huntsman and former U.S. House Speaker Newt Gingrich of Georgia.

The results are hardly predictive of who will win the state’s winter precinct caucuses but the outcome can shape the race for the months ahead.

With the victory, Bachmann is all but certain to get a jolt of momentum just as Perry seeks to infringe on her base of tea party and evangelical support. She also made clear that she has a strong get-out-the-vote operation and a wide volunteer base in a state whose caucuses require those elements.