Empirical research lends support to the idea of a, "multi-speed globe," of differentiated (fragmented) constitutionalisation, rather than a fully-fledged integrative constitutional process. "Variable geometry," on the global scale could acknowledge irreconcilable differences between nation states.A prominent candidate for one fragment of this variable global constitutionalisation is the World Trade Organization (WTO). Constitutionalisation of the WTO means an evolution from constitution to constitutionalism within this organisation.A core constitutional issue is the public interest. The concept of, "public interest," can be used in various ways. Exception and limitation clauses play an important role in the constitutionalist reconstruction of international law.The WTO is so far only modestly constitutionalised, but could and should be further constitutionalised. Further constitutionalisation of the WTO should comprise the following reforms: upgrading non-trade concerns such as the environment in the treaty language itself, liberalisation in trade sectors in which poor countries can compete, empowerment of individuals by enabling at least indirect participation in secondary law-making (parliamentary dimension) and dispute settlement (direct effect), streamlining of the decision-making and law-making processes by reviving the legally available options for majority voting and judicial review of WTO acts.