The most traumatic loss the U.S. military has suffered to date in the war with Iraq may, ironically, have been inflicted not by Iraqi Republican Guards, regular army units or irregular "Fedayeen." Rather, it may have come at the hands of an American servicemen. Early Sunday morning Kuwait time, a sergeant assigned to an engineering brigade of the 101st Airborne Division allegedly attacked three tents in which many divisional commanding officers were sleeping on the eve of their unit's jump-off into Iraq.