Accompanied by U.S. Secret Service agents, Republican presidential candidate, former Massachusetts Gov. Mitt Romney greets supporters as he campaigns at Integrity Windows in Roanoke, Va., Thursday, Nov. 1, 2012. (AP Photo/Charles Dharapak)

Photo by: Charles Dharapak

Accompanied by U.S. Secret Service agents, Republican presidential candidate, former Massachusetts Gov. Mitt Romney greets supporters as he campaigns at Integrity Windows in Roanoke, Va., Thursday, Nov. 1, 2012. (AP Photo/Charles Dharapak)