Republican presidential candidate and former Massachusetts Gov. Mitt Romney campaigns with Sen. Rob Portman, Ohio Republican, in front of The Golden Lamb inn and restaurant in Lebanon, Ohio, Saturday, Oct. 13, 2012. (AP Photo/Charles Dharapak)
Republican presidential candidate and former Massachusetts Gov. Mitt Romney talks to supporters as he campaigns in Lebanon, Ohio, Saturday, Oct. 13, 2012. (AP Photo/Tom Uhlman)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney, speaks during a campaign rally at Shawnee State University, Saturday, Oct. 13, 2012, in Portsmouth, Ohio. (AP Photo/David Kohl)
** FILE ** In these Sept. 26, 2012, file photo, President Barack Obama and Republican presidential candidate Mitt Romney both campaign in the battleground state of Ohio. (AP Photos)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney walks with Sen. Rob Portman, R-Ohio, as he arrives in Richmond, Va., Friday, Oct. 12, 2012. (AP Photo/Charles Dharapak)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands during a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012 in Asheville, N.C. (AP Photo/ Evan Vucci)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands during a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012 in Asheville, N.C. (AP Photo/ Evan Vucci)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands during a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012 in Asheville, N.C. (AP Photo/ Evan Vucci)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands with supporters at a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012, in Asheville, N.C. (AP Photo/Matt Rose)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney gestures as he speaks during a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012 in Asheville, N.C. (AP Photo/ Evan Vucci)
Supporters of Republican presidential candidate, former Massachusetts Gov. Mitt Romney listen to him speak during a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012 in Asheville, N.C. (AP Photo/ Evan Vucci)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks during a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012 in Asheville, N.C. (AP Photo/ Evan Vucci)
Republican presidential candidate, former Massachusetts Gov. Mitt Romney waves as he arrives for a campaign rally at the U.S. Cellular Center on Thursday, Oct. 11, 2012 in Asheville, N.C. (AP Photo/ Evan Vucci)