Secretary Gates and Adm. Mike Mullen testify at a hearing of the Senate Armed Services Committee. Secretary of Defense Robert M. Gates and Chairman of the Joint Chiefs of Staff Adm. Mike Mullen testify at a hearing of the Senate Armed Services Committee on operations in Libya at the Dirksen Senate Office Building in Washington, D.C., on March 31, 2011. SHARE: Download: Full Size (0.04 MB) Credit: VIRIN: 007231-V-WTH39-104.jpg Photo Gallery