Two notions constantly re-emerge in present-day research on issues arising under the general heading of constitutionalization of international law: sovereignty and cosmopolitanism. The former is regarded as being rather an impediment to the projects of international constitutionalism, the latter as a distant future goal, but both to be reinterpreted and readapted to modern realities and aspirations of researchers engaged in the theorization of international constitutionalism.
The three books under review, which appeared during the last three years, represent an excellent illustration of the relationship and tensions existing between sovereignty, cosmopolitanism, and the project of a constitutionalization of international law. It is significant that the titles of two of these books are formulated as questions. Many uncertainties dominate the field. The first and one of the most important of these uncertainties relates to the notion of sovereignty. Ulrich Haltern in his book entitled What does sovereignty mean? (Was bedeutet Souveränität?) attempts to shed more light on some ways in which the notion of sovereignty continues to shape our understanding of the political and on reasons for the continuing relevance of sovereignty in the modern world, including international law.
Haltern describes his approach as a political theology of the notion of sovereignty (politische Theologie des Souveränitätsbegriffs) (at 10). He provides an explanation of one of the paradoxes at the core of the project of international constitutionalism, namely that between increased sophistication of theoretical arguments developed by international lawyers to demonstrate the relevance and force of international law beyond the mere will of states and the continuing political practice of the imposition of the will of dominant state(s) on the world contrary to international rules and prescriptions. Sometimes this paradox is explained in terms of the insufficiency of international law's enforcement mechanisms. This explanation is viewed by Haltern as too simplistic (at 8). �