In the debates about whether to take constitutionalism beyond the state, the European Union invariably looms large. One element, in particular, that invites scholars to grapple with the analogy between the European Union and global governance is the idea of legal pluralism. Just as the European legal order is based on competing claims of ultimate legal authority among the European Union and its member states, so, too, the global legal order, to the extent that we can speak of one, lacks a singular, uncontested hierarchy among its various parts. To be sure, some have argued that the UN Charter provides for a basic ordering of the international legal system akin to a constitutional charter. Others urge us to view the World Trade Organization as the foundation for global constitutional order. And yet legal and institutional fragmentation among the various regimes in the international arena broadly persists, as in the unsettled relationship among, say, trade, environmental, and human rights regimes. Moreover, with regard to the basic normative hierarchy as between domestic and international legal orders, the old debate between monism and dualism has run its course and the practical result is a tie. The international legal order claims autonomy from, and authority over, the state, whereas the state, in turn, claims primacy in the creation, direction, and implementation of international law.
With regard to the European Union itself, some take the lack of conclusive ordering as a sign of the absence of constitutionalism.