President Barack Obama participates in a wreath laying ceremony during the September 11th Observance Ceremony at the Pentagon (September 11, 2012)

President Barack Obama participates in a wreath laying ceremony during the September 11th Observance Ceremony at the Pentagon Memorial in Arlington, Va., Sept. 11, 2012. First Lady Michelle Obama, Defense Secretary Leon Panetta, Mrs. Deanie Dempsey and Gen. Martin Dempsey, Chairman of the Joint Chiefs of Staff, stand behind the President. (Official White House Photo by Pete Souza)