Adm. Mike Mullen administers the oath of office to Army. Gen. Martin E. Dempsey
Outgoing Chairman of the Joint Chiefs of Staff Adm. Mike Mullen, left, administers the oath of office to Army. Gen. Martin E. Dempsey, as the 18th chairman of the Joint Chiefs of Staff during the change of responsibility ceremony at Summerall Field, Joint Base Myer-Henderson Hall, Va., on Sept. 30, 2011.