Customary International Law: A New Theory with Practical Applications

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Customary international law, although long recognized as a primary sources of international law, remains replete with enigmas, both conceptual and practical. These include how to determine the existence of opinion 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.

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Editorial Reviews

From the Publisher
"This volume occupies a unique niche in public international law theory: a superb treatment of sources of international obligation, as well as foundational ethics. Brian Lepard is as a leading moral philosopher of the field."
David J. Bederman, K.H. Gyr Professor of Private International Law, Emory University School of Law

"[T]his book presents an engaging, original and appealingly coherent contribution to the theory of CIL... Customary International Law is a valuable piece of scholarship worth reading for anyone interested in the conceptual problems raised by CIL."
Review in the Journal of International Law and Politics

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Product Details

Meet the Author

Brian D. Lepard is Law Alumni Professor of Law at the University of Nebraska College of Law and co-director of the university's Human Rights and Human Diversity Initiative. Professor Lepard has served as Chair of the International Legal Theory Interest Group of the American Society of International Law. His books include Hope for a Global Ethic: Shared Principles in Religious Scriptures (2005) and Rethinking Humanitarian Intervention: A Fresh Legal Approach Based on Fundamental Ethical Principles in International Law and World Religions (2002). His articles have appeared in such journals as the Duke Journal of Comparative & International Law and the Journal of Human Rights.

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Table of Contents

Figures xi

Acknowledgments xiii

Cases xv

part 1 The Enigmas of Customary International Law

1 The Need for a New Theory 3

2 Some Conceptual Enigmas 14

3 Some Practical Enigmas 30

part 2 Foundations of A New Theory of Customary International Law

4 Clarifying the Concept of Authoritative International Legal Norms 47

5 Fundamental Ethical Principles and Customary International Law 77

Part 3 Resolving The Conceptual Enigmas of Customary International Law

6 Toward a New Normative Theory of Customary International Law 97

7 A New Understanding of Opinio Juris 112

8 The Function of the State Practice Requirement 122

9 Ethics and Customary International Law 140

10 Democratic Principles and Customary International Law 151

11 The Relationship Between Customary International Law and General Principles of Law 162

Part 4 Resolving The Practical Enigmas of Customary International Law

12 General Sources of Evidence of Opinio Juris 171

13 The Role of Treaties as Evidence of Opinio Juris 191

14 The Role of United Nations General Assembly Resolutions as Evidence of Opinio Juris 208

15 The Role of Consistent State Practice 218

16 The Persistent Objector Exception 229

17 Defining Jus Cogens Customary Norms 243

18 Defining Erga Omnes Customary Norms 261

19 Resolving Conflicts with Treaties 270

20 Changing Customary International Law and the Role of International Organizations 277

Part 5 Some Applications of The Theory

21 International Rules on Allocating Income for Tax Purposes 285

22 International Human Rights Law in General 306

23 Determining the Customary Law Status of Specific Human Rights 331

24 The Right to Change One's Religion or Belief346

Part 6 The Future Of Customary International Law

25 Customary International Law as a Dynamic Process 371

Bibliography 381

Index 397

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