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.

This book revisits the theory of the sources of international law from the perspective of formalism. It critically analyzes the virtues of formalism, construed as a theory of law ascertainment, as a means of distinguishing between law and non-law. The theory of formalism is re-evaluated against the backdrop of the growing acceptance by international legal theorists of the blurring of the lines between law and non-law. At the same time, the book acknowledges that much international normative activity nowadays takes place outside the ambit of traditional international law and that only a limited part of the exercise of public authority at the international level results in the creation of international legal rules. The theory of ascertainment that the book puts forward attempts to dispel some of the illusions of formalism that accompany the delimitation of customary international law. It also sheds light on the tendency of scholars, theorists, and advocates to deformalize the identification of international legal rules with a view to expanding international law. The book seeks to revitalize and refresh the formal identification of rules by engaging with some tenets of the postmodern critique of formalism. As a result, the book not only grapples with the practice of law-making at the international level, but it also offers broad theoretical insights on international law, dealing with the main schools of thought in legal theory (positivism, naturalism, legal realism, policy-oriented jurisprudence, and postmodernism). The main theory of law ascertainment presented in this work remains however principally informed by a rejuvenated version of Herbert Hart's social thesis.

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.

Whilst the concept of jus cogens has grown increasingly more important in public international law, lawyers remain hugely divided both over what precisely confers a jus cogens status on a norm, and what this conferral implies in terms of legal consequences. In this ground-breaking book, Ulf Linderfalk clearly and succinctly explores the reasons for this divide in order to facilitate more rational and productive future discourse.