President Obama speaks to a crowd in Cannon Falls, MN, August 15, 2011.
People watch from the side of the road as US President Barack Obama's motorcade passes through Postville, Iowa, August 16, 2011.
President Barack Obama's black bus moves in a motorcade, Monday, Aug. 15, 2011, on the road to Decorah, Iowa.
Staff sits outside the Stephens Auditorium before the Republican presidential debate at Iowa State University in Ames, Iowa, Aug. 11, 2011.
Former Alaska Gov. Sarah Palin takes a photo with Jessica Pray, Miss Iowa 2011, during a stop on the re-launch of her "One Nation" bus tour, at the Iowa State Fair in Des Moines, Iowa, August 12, 2011.
Former Alaska Governor Sarah Palin's toes are painted black with white polka dots while visiting the Iowa State Fair August 12, 2011 in Des Moines, Iowa.
A water glass, its cover featuring the seal of the President of the United States, and a microphone used by Obama at a town hall event are pictured on a stage in Atkinson, IL, August 17, 2011.
Republican presidential candidate and Texas Governor Rick Perry poses with a cutout of SGT James Benal of the Nebraska National Guard at the Iowa State Fair August 15, 2011 in Des Moines, Iowa. Benal's mother poses the cutout in various setting and sends the pictures to her son who is deployed in Afghanistan.
Rep. Ron Paul's campagin set up a tent for free hot dogs outside the Hilton Coliseum, where voted in the Iowa Straw Poll, August 13, 2011 in Ames, Iowa.
President Obama chants "Win the day" with players from the Silver Streaks football team at Galesburg High School, Illinois August 17, 2011.
Newt Gingrich, former House Speaker and Republican presidential candidate, left, orders food at the Iowa State Fair in Des Moines, Iowa, Aug. 11, 2011.
Texas Governor Rick Perry waits offstage as he is introduced to give his speech to announce his campaign for President of the United States during the RedState Gathering at the Francis Marion Hotel in Charleston, SC, Saturday, August 13, 2011.
Republican presidential candidate and former Minnesota Governor Tim Pawlenty talks to voters at the Des Moines Register's Soapbox, August 12, 2011 at the Iowa State Fair in Des Moines, Iowa.
President Obama's dog Bo is led onto Air Force One before Obama's departure from Andrews Air Force Base in Washington to begin his vacation on Martha's Vineyard, Massachusetts, August 18, 2011.
Members of the Secret Service keep watch as President Obama speaks during a town hall meeting at the Country Corner Farm Market in Alpha, IL, August 17, 2011.
After a campaign stop at the Iowa State Fair, Republican presidential candidate Michele Bachmann waves to attendees while leaving, Des Moines, Iowa, August 12, 2011.
President Obama steps on stage to speak in Alpha, IL, August 17, 2011.
Republican presidential candidate, Rep. Ron Paul, waits to be interviewed live at the Republican Party's Straw Poll in Ames, Iowa, August 13, 2011.
Michele Bachmann dances with her husband Marcus Bachmann during a rally with supporters on the campus of Iowa State University in Ames, Iowa, August 12, 2011.
A volunteer for Republican presidential hopeful Ron Paul ties balloons to a barrier at the Iowa Republican Straw Poll on August 13, 2011 in Ames, Iowa.
Republican presidential candidate Michele Bachmann and her husband Marcus Bachmann ride from the the Hilton Coliseum on a golf cart at Iowa State University, August 13, 2011.
Attendees of the Ames Straw Poll at Iowa State University in Ames, Iowa, leave a rally for Republican presidential candidate Michele Bachmann, August 13, 2011.