FILE - This Oct. 24, 2012 file photo shows President Barack Obama gestures while speaking to supporters during a campaign stop at The Mississippi Valley Fairgrounds in Davenport, Iowa. President Barack Obama and Republican rival Mitt Romney are on guard for anything that could tip a presidential race that polls show is close. An autumn surprise is just that, making most late-breaking events tough to plan for. (AP Photo/Charlie Neibergall, File)
