Secrecy Paramount on Obama Kabul Mission in 36 Hours of Darkness

Secrecy Paramount on Obama Kabul Mission in 36 Hours of Darkness

Mandel Ngan/AFP/Getty Images

President Barack Obama is greeted by Lieutenant General Curtis Scaparrotti, left, and US Ambassador to Afghanistan Ryan Crocker upon arrival at Bagram Air Field, in Afghanistan, on May 1, 2012.