WASHINGTON - NOVEMBER 20:  Senate Armed Services Committee Chairman Carl Levin (D-MI) heads for a closed-door briefing with military officials in the Russell Senate Office Building November 20, 2009 in Washington, DC. The committee received a closed-door briefing from Army officials where they reviewed files about Maj. Nidal Hasan, the alleged perpetrator of the Fort Hood shooting. Getty Images logo Getty Images 2 months ago

WASHINGTON - NOVEMBER 20: Senate Armed Services Committee Chairman Carl Levin (D-MI) heads for a closed-door briefing with military officials in the Russell Senate Office Building November 20, 2009 in Washington, DC. The committee received a closed-door briefing from Army officials where they reviewed files about Maj. Nidal Hasan, the alleged perpetrator of the Fort Hood shooting.