Republican U.S. presidential candidates former U.S. Senator Rick Santorum (L), Louisiana Governor Bobby Jindal (C) and U.S. Senator Lindsey Graham talk at the conclusion of a debate between the lowest polling candidates held before the second official Republican presidential candidates debate of the 2016 U.S. presidential campaign at the Ronald Reagan Presidential Library in Simi Valley, California, United States, September 16, 2015. REUTERS/Lucy Nicholson