Republican presidential candidate and former Massachusetts Gov. Mitt Romney greets supporters May 10, 2012, during a campaign stop in Omaha, Neb. (Associated Press/Omaha World-Herald)

Photo by: Alyssa Schukar

Republican presidential candidate and former Massachusetts Gov. Mitt Romney greets supporters May 10, 2012, during a campaign stop in Omaha, Neb. (Associated Press/Omaha World-Herald)