International Constitutional Law

Abstract

The notion “international constitutional law” refers to norms of public international law with a constitutional character or function. Thus understood, international constitutional law can be divided into three broad subcategories: (1) fundamental norms which serve a constitutional function for the international legal system at large, (2) norms which serve as constitutions of international organizations or regimes, and (3) norms which have taken over or reinforce constitutional functions of domestic law. Already the fundamental rules of the Westphalian state system that allocate competences and delineate spheres of state jurisdiction could be referred to as constitutional law of the international legal order. Since then, new layers of constitutional law have been added in the course of a long-term process, changing international law from an interstate order into an order which is also committed to the international community and to the individual. These added contents of international law restrain free “state will” and strengthen the autonomy of international law vis-a-vis state sovereignty. Figuratively speaking, modern international law no longer is solely the product of state consent but has a constitution of its own. Still, compared to domestic constitutions, the participation of individuals, their status activus in international legal processes, is extremely underdeveloped. The constituent instruments of international organizations constitute a second category of international constitutional law. They establish international organizations as legal entities; define their purposes, powers, and fundamental principles; establish rules on the admission of new members; and set up special procedures and majority rules for amendment. A “constitutional” understanding of institutional law is ambivalent. On the one hand, this understanding characterizes founding treaties as “living instruments” and thereby justifies a dynamic interpretation of their powers. On the other hand, it may restrict the ambitions of international organizations in the light of human rights concerns or based on constitutional doctrines such as institutional balance or separation of powers. Finally, certain norms of international law may be qualified as constitutional because they function as a supplementary constitutional law in the domestic context. This is particularly obvious for international human rights law, which constrains state action that risks violating those norms. Also, beyond human rights, international law regulates domestic governance to an unprecedented extent. For example, it prescribes that new states can only come into being if they are organized in a democratic fashion. Some regard WTO law as a “second line of constitutional entrenchment” to grant economic freedoms of market actors. In general, some authors distinguish global constitutional law from international constitutional law by its inclusion of private lawmaking actors, while others use these terms interchangeably.