Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands with supporters as he campaigns at Jet Machine, which supplies components for the defense, aerospace, and oil and gas industry, Thursday, Oct. 25, 2012, in Cincinnati, Ohio. At right is a U.S. Secret Service agent. (AP Photo/Charles Dharapak)

Photo by: Charles Dharapak

Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands with supporters as he campaigns at Jet Machine, which supplies components for the defense, aerospace, and oil and gas industry, Thursday, Oct. 25, 2012, in Cincinnati, Ohio. At right is a U.S. Secret Service agent. (AP Photo/Charles Dharapak)