Vice President Biden and his Republican opponent, Rep. Paul Ryan of Wisconsin, participate in the vice presidential debate at Centre College in Danville, Ky., Thursday. Charlie Neibergall/AP hide caption

itoggle caption Charlie Neibergall/AP

Sen. Lloyd Bentsen (D-Texas) shakes hands with Sen. Dan Quayle (R-Ind.) before their vice presidential debate at the Omaha Civic Auditorium in Omaha, Neb., on Oct. 5, 1988. Ron Edmonds/AP hide caption

itoggle caption Ron Edmonds/AP