Is international law "Europeanized"? If so, what are the implications of such "Europeanization" for the unity and coherence of international law? This paper claims, first, that the application of international law by domestic courts in Europe does not threaten the unity of international law. There may be good reasons for domestic courts not to give effect to international law, based on democratic legitimacy, internal balance of powers or reciprocity with other nations. Yet, the risk of fragmentation or inconsistent interpretations is not one of them. Second, the definition and pursuit of a European agenda or European approach to international law does not threaten the unity of international law. Europe must shed its reluctance to define, and aggressively pursue, such agenda based on European values and interests. Third, and most importantly, when scratching the surface of today's conventional wisdom of Europe as the defender of international law and America as its antithesis, the attitudes, mental framework and reflexes as well as prevailing concerns are strikingly similar across the Atlantic. Most differences in approach are explained not by inherent, substantive disagreements between Europe and the US, but rather by relative power positions and internal constitutional features.
Joost H. B. Pauwelyn, Europe, America and the “Unity” of International Law (2005)