The General Admission of Aliens under International Law

One often reads or hears that a state has a right to exclude all aliens from its territory unless a treaty obligation requires admission. Frequently, that proposition prefaces discussion of such issues as immigration quotas, expulsion and deportation of aliens, justiciability and procedural due process in litigation involving immigration questions, and the duty of states to protect aliens. Sometimes the proposition is colored by such words as “of course,” “no longer open to serious question,” or “unquestionably”—clues, at least, that some questions and doubts may be in order.