Based on vital terms such as ""action"" and ""system"", this volume has conducted an investigation into the ""auspices"" or the fundamental international sociological conditions over which international law is built, and accordingly, into how international law can control global relations.;The significance of this work lies in its aim of showing, by the application of a consistent logic, how complex observed phenomena can be explained and understood on the basis of certain shared fundamental perceptions drawn from common experience. By asking how a state acts in a complex system that consists of at least two subsystems having different goals and different logics, two specific issues are discussed: the relationship between domestic and international law, namely, that between Article 9 of the Constitution of Japan and the UN Charter (especially the provisions for a collective security system as mentioned in chapter VII); and the relationship between international law and international politics, namely, the relationship between the prohibition of the use of nuclear weapons and the logic of nuclear deterrence.