A Canadian citizen who has been held at Guantánamo since he was 15 years old will appear before a military commission hearing today. Omar Khadr is the first prisoner at Guantánamo to be arraigned since a military appeals court found they had the right to assign the label “unlawful enemy combatants” to detainees last June. Khadr’s attorneys say he has been repeatedly tortured, threatened with rape and tied up for hours in painful positions. Khadr told his attorneys that U.S. military guards once used him as a human mop to clean urine on the floor.