Republican presidential candidate and former Massachusetts Gov. Mitt Romney is seen in silhouette as he boards his campaign charter plane while the sun sets in Cleveland, Ohio, Friday, Sept. 14, 2012, after holding a campaign rally and fundraising events. (AP Photo/Charles Dharapak)
Republican presidential candidate and former Massachusetts Gov. Mitt Romney campaigns in the rain at Lake Erie College in Painesville, Ohio, Friday, Sept. 14, 2012. (AP Photo/Charles Dharapak)
** FILE ** Republican presidential candidate, former Massachusetts Gov. Mitt Romney, embraces his wife Ann before he boards his campaign charter plane in Jacksonville, Fla., Wednesday, Sept. 12, 2012. (AP Photo/Charles Dharapak)
Republican presidential candidate Mitt Romney makes comments Sept. 12, 2012, while speaking in Jacksonville, Fla., on the killing of U.S. Embassy officials in Benghazi, Libya. (Associated Press)
Republican presidential candidate Mitt Romney makes comments Sept. 12, 2012, while speaking in Jacksonville, Fla., on the killing of U.S. Embassy officials in Benghazi, Libya. (Associated Press)
Republican presidential candidate and former Massachusetts Gov. Mitt Romney arrives in Jacksonville, Fla., Tuesday, Sept. 11, 2012. (AP Photo/Charles Dharapak)
** FILE ** In this June 28, 2012, photo Republican presidential candidate Mitt Romney speaks about the Supreme Court's health care ruling near the U.S. Capitol. (AP Photo/Charles Dharapak)