‘What about Guantánamo?’ considers military commissions, which are a category of military tribunal. They are not courts-martial because they are not used to prosecute offenses committed by US military personnel. Traditionally, they have been used in three situations: where martial law has been declared, in occupied areas, and where permitted by the law of war. Hundreds of military commissions were conducted during and after the Civil War, and again after World War II to prosecute war criminals. They were revived after 9/11 by President George W. Bush to prosecute unlawful enemy combatants, with hundreds of captives transported from Afghanistan and other places to Guantánamo Bay, Cuba, where the vast majority were interrogated and simply imprisoned.