Republican presidential candidate, former Massachusetts Gov. Mitt Romney meets with workers as he campaigns at Acme Industries in Elk Grove Village, Ill.,Tuesday, Aug. 7, 2012. (AP Photo/Charles Dharapak)

Mitt Romney

Republican presidential candidate, former Massachusetts Gov. Mitt Romney campaigns at Acme Industries in Elk Grove Village, Ill.,Tuesday, Aug. 7, 2012. (AP Photo/Charles Dharapak)

Republican presidential candidate, former Massachusetts Gov. Mitt Romney leaves the stage after speaking at Acme Industries in Elk Grove Village, Ill.,Tuesday, Aug. 7, 2012. (AP Photo/Charles Dharapak)

Republican presidential candidate, former Massachusetts Gov. Mitt Romney gets a hug as he campaigned at Acme Industries in Elk Grove Village, Ill.,Tuesday, Aug. 7, 2012. (AP Photo/Charles Dharapak)

Republican presidential candidate, former Massachusetts Gov. Mitt Romney meets workers as he campaigns at Acme Industries in Elk Grove Village, Ill.,Tuesday, Aug. 7, 2012. (AP Photo/Charles Dharapak)

Republican presidential candidate, former Massachusetts Gov. Mitt Romney steps off his charter plane in Chicago before campaigning at Acme Industries in Elk Grove Village, Ill.,Tuesday, Aug. 7, 2012. (AP Photo/Charles Dharapak)

Republican presidential candidate, former Massachusetts Gov. Mitt Romney and Dutchie Caray, widow of famed baseball announcer, Harry Caray, look at the Steve Bartman foul ball which was blown up, and a pair of Harry Caray's glasses after a private fundraising event at Harry Caray's Italian Steakhouse restaurant in Chicago, Tuesday, Aug. 7, 2012. (AP Photo/Charles Dharapak)