Rick Perry, Iowa Straw Poll Turn Republican Presidential Race Upside Down

Bachman's victory, Tim Pawlenty's exit change the dynamics of GOP race.

WASHINGTON, Aug. 14, 2011— -- It was a dramatic reset to the Republican race for president this weekend with a big victory for one candidate, the exit of another and the entrance of a third.

Making the rounds on the morning talk shows today, Michele Bachmann took a victory lap in Iowa this morning after winning the Ames Straw Poll, but the political fight for Iowa's attention has just begun.

"Obama is my strategy," Bachmann said on ABC's "This Week." "I intend to be the nominee of the Republican Party and to take him on and to defeat him in 2012."

Former Minnesota Gov. Tim Pawlenty announced today that he is dropping out of the presidential contest, after a disappointing third-place finish in the straw poll.

"We needed to get some lift to continue on and have a pathway forward," Pawlenty said this morning in an exclusive interview on "This Week." "That didn't happen, so I'm announcing this morning on your show that I'm going to be ending my campaign for president."

Perhaps the bigger game changer in the Republican presidential field Saturday happened 1,200 miles away from Iowa with Texas Gov. Rick Perry announcing his candidacy at a Republican gathering in South Carolina.

"It is time to get America working again, and that's why with the support of my family and unwavering belief in the goodness of America, I declare to you today as a candidate for president of the United States," Perry said.

Perry, who will now challenge Bachmann for the social and Christian conservative vote, made his first appearance as a presidential candidate in Iowa tonight.

Perry's first stop in Iowa was in Bachmann's hometown of Waterloo. And in an apparent challenge to protect her territory, Bachmann changed her schedule and stopped at the same dinner in Waterloo that Perry attended.

As Perry and Bachmann prepare for a political showdown in the Republican presidential primary, the crossing of the two candidates' paths makes for political theater.

"It is almost uncanny that we are having a battle of Waterloo, because in the end only one of these folks is going to be able to survive," ABC News Political Director Amy Walter said.

Although they shared the same room at the event, Perry and Bachmann never met.

Perry sat through Bachmann's speech, which lasted nearly a half-hour, staying until the very end when the Minnesota congresswoman handed out an apple pie to a 100-year-old audience member.

They were about one table-length away from each other the entire time

But Perry rushed out through a back entrance after her remarks, while Bachmann shook hands with the crowd. Bachmann was not in the room when Perry spoke, choosing instead to wait for several minutes after his remarks were finished to enter the ballroom.

Notably, the Bachmann campaign specifically requested that event organizers change the lighting in the ballroom here for her speech. They were much brighter during her remarks that for Perry's.

Bachmann campaign manager Ed Rollins told reporters after the event that there would be "plenty of opportunities" for the two to meet in the future.

While Iowa has been full of Republican presidential hopefuls in recent days and weeks, it's about to get more crowded yet with President Obama hitting the campaign trail Monday.

Coming off a week of downgrades and stock market uncertainty, President Obama is preparing to push back against the Republican candidates who have been picking apart his economic record by kicking off a three-day bus tour tomorrow.

"Over the coming weeks, I'll put forward more proposals to help our businesses hire and create jobs," Obama said Saturday in his weekly address.

The president's bus tour begins Monday in Minnesota and then will move through Iowa. At the same time the president will criss-cross Iowa in his bus, Perry will be cruising the Iowan interstates in his own bus tour.

As Perry seeks to gain the approval of Iowans after bypassing the straw poll, Obama will work to re-connect with voters and refocus his message.

"This is a president that needs to get back on his feet, change the discussion, change the focus from all the things that Washington is doing wrong and take it directly out to the people," Walter said.

ABC News' Michael Falcone and Arlette Saenz contributed to this report.