Is Treaty Interpretation an Art or a Science? International Law and Rational Decision Making

Although treaty interpretation is undoubtedly an activity governed by international law, and by Articles 31–33 of the 1969 Vienna Convention on the Law of Treaties (VCLT) in particular, some commentators continue repeating the pre-Vienna adage that treaty interpretation is a matter of art and not science, the implication of which is that no understanding of a treaty provision can ever be explained rationally. As the present article argues, this idea of interpretation must be rejected. While, sometimes, an assumed meaning of a treaty cannot be justified based on international law simpliciter, many times it can still be explained based on the structural framework of Articles 31–33 of the VCLT. Consequently, any characterization of treaty interpretation in the abstract as either art or science is misplaced. Whether treaty interpretation is an art or a science remains a question of fact inextricably tied to the approach taken by each and every law-applying agent in particular cases.