Gen. David H. Petraeus leaves command of U.S. and NATO-led forces in Afghanistan to Gen. John Allen during Monday's change-of-command ceremony in Kabul. Gen. Allen assumes responsibility for drawing up exit plans for U.S. and allied forces from the nearly 10-year war zone. (Associated Press)

Gen. David H. Petraeus leaves command of U.S. and NATO-led forces in Afghanistan to Gen. John Allen during Monday's change-of-command ceremony in Kabul. Gen. Allen assumes responsibility for drawing up exit plans for U.S. and allied forces from the nearly 10-year war zone. (Associated Press)