Then-CIA Director David Petraeus testifies on worldwide threats before the Senate Select Committee on Intelligence, on Jan. 31. Zhang Jun/Xinhua /Landov hide caption

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Then-Army Gen. David Petraeus (left) and Marine Corps Gen. John Allen in August, 2011. Chip Somodevilla/Getty Images hide caption

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Then-Gen. David Petraeus in mid-2011, just before he became CIA director. Barbara Sax/AFP/Getty Images hide caption

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U.S. Marines with 1st Platoon, Company I, 3rd Battalion, 5th Marines (3/5), Regimental Combat Team 2, in Afghanistan. (January 2010 file photo.) Corporal David R. Hernandez/3rd Battalion 5th Marines-RCT 2 hide caption

itoggle caption Corporal David R. Hernandez/3rd Battalion 5th Marines-RCT 2

Aug. 13: At Dover Air Force Base in Delaware, the remains of Marine Lance Cpl. Gregory T. Buckley are carried during a dignified transfer. He was killed in a "green on blue" attack. Mark Wilson/Getty Images hide caption

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