The due process rights of suspected terrorists have played a major role in the debate about how best to engage terrorist entities after September 11, 2001. Does citizenship or immigration status have a bearing on the treatment of terrorists? Does location within or outside the United States matter? This Article explores the connection between citizenship and alienage, enemy status, allegiance, and due process rights against a backdrop of international law. It surveys the application of due process to citizens and aliens based on the location of misconduct within or outside the territory of the United States and notes the expansion of criminal law to cover ever more extraterritorial conduct, including that of noncitizens who otherwise have no connection to the United States. It concludes by suggesting that the fairness of a particular exercise of extraterritorial criminal jurisdiction might be determined by looking at the nature of the obligation that a defendant owes to the state based on international law.