U.S. Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, talks to American service members with the International Security Assistance Forces in Kabul, Afghanistan, on Monday, Aug. 20, 2012. (AP Photo/D. Myles Cullen, Department of Defense)

Photo by: D. Myles Cullen

U.S. Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, talks to American service members with the International Security Assistance Forces in Kabul, Afghanistan, on Monday, Aug. 20, 2012. (AP Photo/D. Myles Cullen, Department of Defense)