KABUL, AFGHANISTAN - SEPTEMBER 30:  Afghan National Security Advisor Hanif Atmar (Front R) and US Ambassador to Afghanistan James Cunningham (Front L) exchange documents after signing the bilateral security agreement as Afghan President Ashraf Ghani (3rd R), vice President Abdul Rashid Dostum (2nd R), chief executive Abdullah Abdullah (3rd L) and former President Sebghatullah Mujadidi (2nd L) look on at the Presidential Palace in Kabul, Afghanistan, on September 30, 2014. (Photo by Afghan Presidency Press Office/Anadolu Agency/Getty Images)