Along with treaties, custom is one of the sources of international law. It is known to consist of two elements: state practice and opinio juris. While many studies have looked at traditional questions of how to identify customary law, this book takes a new and original approach. It looks instead at the structure of thought that lies beneath the arguments about customary international law. By examining these structures, the book uncovers surprising conclusions, and demonstrates what the author describes as the 'discursive splendour' of customary international law. The book guides the reader through an analysis of eight distinct performances at work in the discourse on customary international law. One of its key claims is that customary international law is not the surviving trace of an ancient law-making mechanism that used to be found in traditional societies. Indeed, as is shown throughout, customary international law is anything but ancient, and there is hardly any doctrine of international law that contains so many of the features of modern thinking. It is also argued that, contrary to mainstream opinion, customary international law is in fact shaped by texts, and originates from a textual environment. This book provides an engaging account of customary international law, whilst challenging readers to rethink their understanding of this fundamental part of the discipline.

This book sets out to articulate a comprehensive theory of customary international law that can effectively resolve the conceptual and practical enigmas surrounding it. It takes a multidisciplinary approach and draws insights from international law, legal theory, political science, and game theory. It is anchored in a sophisticated ethical framework and explores the interrelationships between customary international law and ethics.

Offers a new perspective on international law and international legal argumentation: to what event is international law a belief system?

This book comes out at a time of grave uncertainty about the content and the very existence of international legal restraints on the use of force, in the international community as well as among legal scholars. The time is therefore ripe for an in-depth analysis on the methodological issues which constitute the basic bricks on which the legal discourse about the state of the law must be built. By offering the result of an open and frank discussion about the methodology of determining the law on the use of force "at a time of perplexity", this timely book constitutes an invaluable contribution to legal analysis.

Some legal rules are not laid down by a legislator but grow instead from informal social practices. In contract law, for example, the customs of merchants are used by courts to interpret the provisions of business contracts; in tort law, customs of best practice are used by courts to define professional responsibility. Nowhere are customary rules of law more prominent than in international law. The customs defining the obligations of each State to other States and, to some extent, to its own citizens, are often treated as legally binding. However, unlike natural law and positive law, customary law has received very little scholarly analysis. To remedy this neglect, a distinguished group of philosophers, historians and lawyers has been assembled to assess the nature and significance of customary law. The book offers fresh insights on this neglected and misunderstood form of law.

This book has the ambition to enlighten the methodological issues which constitute the basic bricks on which the legal discourse about the state of the law must be built. By offering the result of an open and frank discussion about the methodology of determining the law at a time of perplexity, this book may constitute a valuable contribution for legal analysis of the use of force.

A collection of essays on the various aspects of the legal sources of international law, including theories of the origin of international law, explanation of its binding force, normative hierarchies and the relation of international law and politics.

Customary international law, although long recognized as a primary source of international law, remains replete with enigmas, both conceptual and practical. These include how to determine the existence of opinio juris, the function of the state practice requirement, the definition of jus cogens customary norms, and the relationship between customary international law and ethics. In part because of these enigmas, the subject has generated a wide-ranging literature. However, no recent book-length work has attempted to articulate a comprehensive theory of customary international law that can effectively resolve these questions. This book sets out to accomplish this goal. Its approach is unique in a number of ways. For example, it is multidisciplinary and draws insights from fields such as legal theory, philosophy, political science, and game theory. In addition, it is anchored in a sophisticated ethical framework and explores at length the interconnections between customary international law and ethics.

Provides an in-depth study of the theory, history, practice, and interpretation of customary international law.