Khalid Sheikh Mohammed and four alleged 9/11 co-conspirators faced a military tribunal at Guantánamo Bay on Saturday in what is their first public appearance in three years. The arraignment quickly devolved as the defendants did everything they could to disrupt proceedings. Mohammed refused to answer a judge's questions. A co-defendant, Walid bin Attash, was put in a restraint chair, but then was removed from it after he agreed to behave. The defendants are charged with 2,976 counts of murder.