This book examines the evolution of customary international law (CIL) as a source of international law. Using the International Criminal Tribunal for the former Yugoslavia (ICTY) as a key case study, the book explores the importance of CIL in the development of international criminal law and focuses on the ways in which international criminal tribunals can be said to change the ways in which CIL is formed and identified. In doing so, the book surveys the process and substance of CIL, as well as the problematic distinction between the elements of state practice and opinio juris. By applying an inclusive positivist approach, Noora Arajarvi analyses the methodologies of identification of CIL in selected cases of the ICTY, and their normative foundations. Through examination of the case-law and the reasoning of courts and tribunals, Arajarvi demonstrates to what extent the court's chosen method of identification of CIL affects the process of custom formation and the resulting system of norms in general. The book will be of great value to researchers and scholars of international law, international relations, and practitioners with interests in customary international law.

Although customary international law (CIL) has been central to international law from its inception, it is often misunderstood. This edited volume remedies that problem by tracing the history of CIL and provides an in-depth study of its theory, practice, and interpretation. Its chapters tackle the big questions which surround this source of international law such as: what are the rules that regulate the functioning of CIL as a source of international law? Can CIL be interpreted? Where do lines between identification, interpretation, application, and modification of a rule of CIL lie? Using recent developments, this volume revisits old debates and resolves them by proffering new and innovative solutions. With detailed examples from international and national courts, it places CIL in a range of settings to explain, explore and reflect upon this developing and highly significant field. This title is also available as Open Access on Cambridge Core.

This book examines the evolution of customary international law (CIL) as a source of international law. Using the International Criminal Tribunal for the former Yugoslavia (ICTY) as a key case study, the book explores the importance of CIL in the development of international criminal law and focuses on the ways in which international criminal tribunals can be said to change the ways in which CIL is formed and identified. In doing so, the book surveys the process and substance of CIL, as well as the problematic distinction between the elements of state practice and opinio juris. By applying an inclusive positivist approach, Noora Arajarvi analyses the methodologies of identification of CIL in selected cases of the ICTY, and their normative foundations. Through examination of the case-law and the reasoning of courts and tribunals, Arajarvi demonstrates to what extent the court's chosen method of identification of CIL affects the process of custom formation and the resulting system of norms in general. The book will be of great value to researchers and scholars of international law, international relations, and practitioners with interests in customary international law.