WASHINGTON (CNN) -- As the military investigates two reports of Marines in Iraq allegedly killing innocent civilians, Gen. Michael Hagee, commandant of the Marine Corps, left for Iraq on Thursday to talk about use of force. According to a statement released by the Marine Corps, Hagee is expected to address the core values of honor, courage and commitment, and "the risk of becoming indifferent to the loss of a human life." "We do not employ force just for the sake of employing force. We use lethal force only when justified, proportional and, most importantly, lawful," Hagee will tell the Marines,...