How can social order beyond the level of the nation-state emerge, be maintained, or further develop under conditions of profound change? The changes occurring in world politics in the past few decades require a new mix between coercion, selfinterest, or legitimacy as the possible modes by which order can be established beyond the nation-state. These three modes of social order are not fully congruent with the categorization of power, interest, or knowledge as variables which are usually used for explaining outcomes and behavioral changes in world politics (Hasenclever, Mayer and Rittberger 1997; Levy, Young and Zürn 1995; Young and Osherenko 1993). This traditional categorization, however, seems no longer justified as far as the mode of knowledge is concerned. The more the character of politics in multi-level governance systems approximates, even though not fully equals, to the pluralist character of domestic politics, the less it remains plausible that studies of domestic or international order rely on partly different understandings with knowledge considered to become relevant on the international level and legitimacy to unfold mainly in domestic politics. Further on, the more international law will constrain the autonomy of political decision-making within the nation-state or will permeate the lifeworld of the people on the domestic level, the more will it become necessary to establish grounds based on social reason which justify to follow or implement international legal norms.1