FILE - In this Oct. 11, 2012, file photo, Democratic Senate candidate Heidi Heitkamp, left, listens to Republican opponent Rick Berg, right, speak at a North Dakota Chamber of Commerce

 

              FILE - In this Oct. 11, 2012, file photo, Democratic Senate candidate Heidi Heitkamp, left, listens to Republican opponent Rick Berg, right, speak at a North Dakota Chamber of Commerce
FILE - In this Oct. 11, 2012, file photo, Democratic Senate candidate Heidi Heitkamp, left, listens to Republican opponent Rick Berg, right, speak at a North Dakota Chamber of Commerce forum on health care and energy at a hotel in Bismarck, N.D. North Dakota’s competitive Senate race is coming down to ticket splitters. Republican presidential hopeful Mitt Romney is expected to easily win the state, which is now enjoying a boom in energy development. But in the race for retiring Democrat Kent Conrad’s seat in the U.S. Senate, GOP Congressman Berg is locked in a bitter battle with the state’s former Democratic attorney general, Heitkamp. (AP Photo/Dale Wetzel, File)