Why Treaty Interpretation and Adjudication Require ‘Constitutional Mind-Sets’

In numerous publications, John Jackson emphasized ‘the strong link between international law and national constitutional systems, which must be understood in order to understand the international economic system’.1 This short contribution in memory of John endorses—and elaborates on—Jackson's proposition that ‘international lawyers must morph into constitutional lawyers’ and adopt a ‘constitutional approach to international law’.2 John's regular visits to the World Trade Organization (WTO) at Geneva and the European Union (EU) institutions at Brussels, like his participation in trade law conferences all over the world, illustrated his ‘cosmopolitan commitment’ (as a ‘citizen of the world’) to building a stronger international legal and mutually beneficial trading community. Yet, his ‘constitutional mind-set’ remained rooted in the unique US constitutional law system rather than in rights-based ‘cosmopolitan constitutionalism’ or market-based ‘economic cosmopolitanism’.