An Interpretive Theory of International Law: The Distinction Between Treaty and Customary Law

The author begins with an explanation of the importance of the distinction between treaty and customary law. The author then presents six alternative principles currently used to inform that distinction (dichotomy, overlap, relativity, interdependence, equivalence, and indeterminacy) and evaluates the application of these principles according to their theoretical coherence, practicability, reconcilability, and resolving power. The author concludes that each of the alternative principles is unsatisfactory in at least one respect and proposes a superior interpretive approach that does not define customary law in terms of treaty, but rather according to its own independently defining attributes. Finally, the author suggests that this approach, called sub-referential threshold relativity (STR), may be applied to other key distinctions in legal doctrine and scholarship.