Re-engaging with the Pure Theory of Law developed by Hans Kelsen and the other members of the Viennese School of Jurisprudence, this book looks at the causes and manifestations of uncertainty in international law. It considers both epistemological uncertainty as to whether we can accurately perceive norms in international law, and ontological problems which occur inter alia where two or more norms conflict. The book looks at these issues of uncertainty in relation to the foundational doctrines of public international law, including the law of self-defence under the United Nations Charter, customary international law, and the interpretation of treaties. In viewing international law through the lens of Kelsen’s theory Jörg Kammerhofer demonstrates the importance of the theoretical dimension for the study of international law and offers a critique of the recent trend towards pragmatism and eclecticism in international legal scholarship. The unique aspect of the monograph is that it is the only book to apply the Pure Theory of Law as theoretical approach to international law, rather than simply being a piece of intellectual history describing it. This book will of great interest to students and scholars of public international law, legal theory and jurisprudence.

One of the most challenging elements during any armed conflict and its aftermath is the need to determine the fate of the missing and to support families dealing with uncertainty. Another layer of complexity is added in cases where a missing person might have been involved in criminal activity. This book examines how international law meets these two distinct, but intertwined, needs. It shows that the duty to account for missing persons is cross-cutting in nature, requiring measures needing implementation before, during, and after armed conflict. At the same time, those measures cannot substitute any required to establish responsibility for IHL/IHRL violations and international crimes. Exploring specific examples, the book examines the role that international law plays in the international community's attempts to articulate humanitarian and accountability-driven efforts when dealing with the missing. By so doing, it suggests how linkages between such efforts can be established, both through legal and policy avenues.

Increasingly, international legal arrangements imagine future worlds or create space for experts to articulate how the future can be conceptualized and managed. With the increased specialization of international law, a series of functional regimes and sub-regimes has emerged, each with their own imageries, vocabularies, expert-knowledge, and rules to translate our hopes and fears for the future into action in the present. At issue in the development of these regimes are not just competing predictions of the future based on what we know about what has happened in the past and what we know is happening in the present. Rather, these regimes seek to deal with futures about which we know very little or nothing at all; futures that are inherently uncertain and even potentially catastrophic; futures for which we need to find ways to identify, conceptualise, manage, and regulate risks the existence of which we can possibly only speculate about. This book explores how the future is imagined, articulated, and managed across the various fields of international law, including the use of force, maritime security, international economic and environmental law, and human rights. It investigates how the future is construed in these various areas; how the costs of risk, risk regulation, risk assessment, and risk management are distributed in international law; the effect of uncertain futures on the subjects of international law; and the way in which international law operates when faced with catastrophic or existential risk.

An exploration into how uncertainty and political and ethical biases affect international law governing the use of force.

Reexamining Customary International Law takes on the complex issues and controversies surrounding the history, theory, and practice of customary international law as it reexamines customary law's increasingly important role in world affairs. It incorporates the expertise of distinguished authors to probe many difficult issues that remain unresolved concerning the doctrine of customary law. At the same time, this book engages in a profound exploration of the practical role of customary international law in a variety of important fields, including humanitarian law, human rights law, and air and space law.

Uncertainty abounds in international law and customary international law is no exception. This article seeks to delineate this uncertainty and explain its causes. Not only is there uncertainty surrounding the exact nature of the two elements considered necessary for custom-formation - state practice and opinio juris - we also do not know how custom-formation works. It is not clear what precisely 'state practice' is, nor do we know how we can have a belief that something is already law in order to create it. The particular uncertainties of customary international law point directly to systemic uncertainties at a higher level. Article 38 of the Statute of the International Court of Justice is convenient, but is it authoritative? What is the basis of our knowledge regarding customary law-making? This article argues that two commonly used approaches to provide a theoretical underpinning - deduction and induction - are fundamentally flawed in their pure forms. Their problems are alleviated, but not solved, by combining them. Without a dominant legal culture and without a written constitution to blind us to other possibilities, not even a pragmatic outlook can save us from uncertainty. However, even where the law is not disputed, it remains an ideal, not real. Law is based on the fiction that it exists.

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.