The Rule of Necessary Implication

Abstract

This chapter examines the so-called 'rule of necessary implication' in treaty interpretation by considering international judicial decisions in three different contexts: implied powers as reflected in decisions of the International Court of Justice and the International Criminal Court; implied jurisdiction in investment treaty arbitration; and necessary implication in the dispute settlement system of the World Trade Organization. In our view, the rule of necessary implication does not form part of customary international law per se but rather reflects treaty interpretation as contained in the Vienna Convention on the Law of Treaties and other customary rules of interpretation. Terms may be implied in a treaty, for example, pursuant to the principle of effectiveness, to give effect to the object and purpose of the treaty, to avoid an absurd result, or to conform with the intentions of the treaty parties.

Keywords: treaty interpretation, treaty law, public international law, international investment law, World Trade Organization, International Court of Justice

JEL Classification: K33