A Few Steps toward an Explanatory Theory of International Law

If any one sentence about international law has stood the test of time, it is Louis Henkin’s: “almost all nations observe almost all principles of international law and almost all of their obligations almost all of the time”. If this is true, why is this true? What makes it true? How do nations invent rules that then turn around and bind them?

Are international rules simply pragmatic and expedient? Or do they embody values such as the need for international cooperation? Is international law a mixed game of conflict and cooperation because of its rules, or do its rules make it a game of conflict and cooperation? It is hard to imagine a set of rules in all of human history that is more important and less understood than the rules of international law.