From left: US President Barack Obama,US Vice President Joe Biden, Deputy Defense Secretary Ashton Carter and Chairman of the Joint Chiefs of Staff General Martin Dempsey take part in a ceremony to mark the return of the US Forces – Iraq colors December 20, 2011 at Andrews Air Force Base in Maryland. The event marks the end of the Iraq war after the last US combat troops rolled out of Iraq into Kuwait on December 18. AFP PHOTO/Mandel NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)