Legal and political science cannot merge, but they should, at the very least, 'listen to each other'. This working paper is a further step in an ongoing interdisciplinary cooperation which seeks to make sense out of Louis Henkin's famous admonition. This co-operation had begun with a research project on the European comitology system in 1995 and the publication, inter alia, of two articles on deliberative supranationalism in 1997. The present article is an effort to go beyond the scope of our original analyses and to explore the potential of our guiding ideas at a more general level of integration research. In Part I of this paper, Jurgen Neyer summarises strands of normative and positive political theory on which deliberative approaches to international and European governance can build. These approaches not only support coherence, social acceptance and normative recognition, they also have in important potential for the design of empirical studies. They seem to be particularly promising for the understanding of the institutional design and the political process in the EU. In Part II, Christian Joerges first summarises the objections against deliberative suprantionalism and comitology in legal science. He then presents a conflict-of-law's approach to European law which builds upon the 1997 articles and seeks to develop their normative-legal perspectives further. European law is interpreted as a new type of conflict of law which constitutionalises a European unitas in pluralitate. Comitology is interpreted as a cognitive opening of the legal system which institutionalises a second order of conflict of laws.