Supremacy Lost: International Law Meets Domestic Constitutional Law

Abstract

The paper is structured as follows: Part A shows that state constitutons increasingly refer to international law and offers some explanations for this trend. Part B demonstrates how international and domestic constitutional law are more and more converging, which also implies that the diverse state constitutions share more and more commonalities. Part C deals with the spreading practice of constitutional interpretation in conformity with international law. Part D argues that in some constitutional orders, international human rights norms assume a para-constitutional function by serving as a standad for judicial review even where constitutional review is not allowed. Part E analyses the supremacy of international law. While the international courts and tribunals claim supremacy over all domestic law, including constitutional law, this claim is rejected by more and more domestic actors. At the same time, more and more domestic courts claim the competence to scrutinize whether international rules and court decisions are in conformity with the domestic constitution.

The survey of constitutional provisions and case law reveals that although domestic constitutions have, especially in the recent decades, been intensely shaped by international law, many constitutional actors, especially constitutional courts, are rejecting international law’s claim to supremacy over domestic constitutional law. Overall, the attitude of domestic constitutional actors towards international law is ambivalent and frequently inconsistent. On the one hand, a ‘vertical’ and ‘horizontal’ convergence of fundamental (and in that sense constitutional) norms relating to human rights, the rule of law, and democracy is visible. On the other hand, a simple hierarchy between international law and national constitutional law, visualised as a pyramid of norms with international law at its apex, is not generally accepted by all players.

This twofold descriptive finding supports the normative suggestion, formulated in Part F, to give up the model of a hierarchical relationship between international law and domestic constitutional law, because this model is on the one hand too far away from the legal practice of the relevant actors and in that sense utopian, and on the other hand not (or no longer) necessary to secure fundamental global values.

Keywords: International Law, Constitutional Law, Domestic Constitutional Law, Pluralism

JEL Classification: K33