President Obama listens to questions during a Monday town hall meeting in Decorah, Iowa. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

Supporters take photos of President Obama at a fundraising kickoff event in Chicago in April. During the heated debate over the debt ceiling, the president canceled several fundraisers in order to focus on negotiations. Nam Y. Huh/AP hide caption

itoggle caption Nam Y. Huh/AP

Republican presidential candidate Michele Bachmann (R-MN), greets Ellie Joy Matthews, 11, of Kansas City, Mo., as she and her family hold signs supporting a balanced budget amendment on Monday, just before the House would vote to pass debt legislation. Jacquelyn Martin/AP hide caption

itoggle caption Jacquelyn Martin/AP

Republican presidential hopeful Rep. Michele Bachmann of Minnesota speaks to the Christian Chamber of Commerce at Christ Central Ministries in Columbia, S.C., on Monday. Brett Flashnick/AP hide caption

itoggle caption Brett Flashnick/AP

While campaigning for president in 2007, Barack Obama, then a senator from Illinois, drove a bumper car with his daughter Sasha at the Iowa State Fair. Scott Olson/Getty Images hide caption

itoggle caption Scott Olson/Getty Images

President Obama greets patrons at Ross' Restaurant in Bettendorf, Iowa, on Tuesday. In 2008, the president's unexpected victory in the state helped propel his campaign. Saul Loeb/AFP/Getty Images hide caption

itoggle caption Saul Loeb/AFP/Getty Images

U.S. Rep. Michele Bachmann greets Irene Blom before speaking at a Presidential Lecture Series sponsored by The Family Leader, April 11, 2011 in Pella, Iowa. Bachmann, along with Herman Cain, Newt Gingrich, Gary Johnson and Rick Santorum, are expected to drop in on a Tea Party Bus Tour making its way through Iowa. Charlie Neibergall/AP hide caption

itoggle caption Charlie Neibergall/AP

Then-Democratic presidential hopeful Barack Obama waves during a May 24, 2008, campaign stop in San Juan, Puerto Rico. Keeping a campaign promise, Obama returns Tuesday. Brennan Linsley/AP hide caption

itoggle caption Brennan Linsley/AP

Republican presidential hopeful, former Mass. Gov. Mitt Romney meets with entrepreneurs at Bizdom U in Detroit on Thursday. Bizdom U is a business development center to help entrepreneurs start up businesses in the state. Carlos Osorio /AP hide caption

itoggle caption Carlos Osorio /AP

Corn is big business in Iowa, which has usually made anything but support for ethanol subsidies off-limits for presidential hopefuls. Steve Pope/AP hide caption

itoggle caption Steve Pope/AP

Former Massachusetts Gov. Mitt Romney focuses on a key issue — corn — in Ankeny, Iowa, on Friday, as he prepares to launch his 2012 presidential bid. Charlie Neibergall/AP hide caption

itoggle caption Charlie Neibergall/AP

George Romney with his wife, Lenore, and teenage son Mitt, after announcing he would seek the Republican nomination for governor of Michigan at a press conference in 1962. AP hide caption

itoggle caption AP

Republican Sen. Rand Paul of Kentucky sharply criticized the Obama administration's decision to intervene in Libya. Brendan Hoffman/Getty Images hide caption

itoggle caption Brendan Hoffman/Getty Images

In a photo released by NBC News, Secretary of State Hillary Clinton and Secretary of Defense Robert Gates discuss Middle East policy on Meet the Press. William B. Plowman/AP hide caption

itoggle caption William B. Plowman/AP