Principles of Treaty Interpretation: Developed for and Applied by National Courts?

Abstract

More than 40 years after the Vienna conference on the law of treaties codified principles of interpretation in the Vienna Convention on the Law of Treaties, their practical operation remains contested and in flux. Neither the ratification of the VCLT by many (though not all) states, nor the general recognition that Articles 31-33 represent customary international law, has resolved the debate over the ‘correct’ approach to interpreting treaties, and international law in general. Debates in international law over the ‘correct’ interpretative approach mirror similar debates in domestic legal systems.Even though the VCLT’s role in treaty interpretation has been studied extensively, its use in how national courts interpret international law has received far less attention. This chapter examines whether the drafters of the VCLT drafted Articles 31-33 partly with national courts in mind, and how national courts in fact interpret treaties. In considering the practical application of the VCLT’s interpretive principles, the chapter largely leaves aside the normative question whether it is desirable for national courts to interpret treaties based on the VCLT, to the exclusion of domestic canons of interpretation.Section II sets the scene for treaty interpretation by national courts. It looks at the development of interpretive principles, and asks whether national courts are among their intended users. Section III considers national judges as members of diverse epistemic communities that influence treaty interpretation and explores the value of the VCLT’s minimum harmonisation of interpretive methods, particularly for uniform, private law-making treaties. Section IV considers the doctrinal question of whether national courts are formally bound by the VCLT’s interpretive principles and the empirical question of whether they routinely apply the VCLT even in the absence of a formal legal obligation to interpret treaties in accordance with the VCLT. Section V examines the persistent tendency for national courts to deploy non-VCLT methodologies such as contract and statutory imagery in interpreting treaties.