Treaties and Subsequent Practice

Under the relevant rules of international law, treaties are interpreted in accordance with the ordinary meaning of the language they use, their object and purpose, and the intention of the drafters, but also in light of the subsequent practice of its parties. This subsequent practice can shed light on articles whose meaning is ambiguous and subsequent agreement can even alter the meaning of treaty provisions. At a time when many of the most important international treaties are more than fifty years old, subsequent practice plays an increasingly important role in their interpretation.

Treaties and Subsequent Practice discusses the role and relevance of this subsequent practice in the process of dynamic treaty interpretation. The book provides a comprehensive treatment of this topic by eminent commentators, combining contributions which focus on practical cases with chapters examining the theoretical underpinnings of treaty interpretation. The concept of subsequent practice is situated in the more general context of treaty law and international law, looking at different cases and doctrinal questions to assess its policy dimensions. The book addresses the question of whether subsequent practice plays a more or less significant role in different areas of international law, and whether it can be employed as a partial substitute for formal treaty amendments. It also includes two previously unpublished reports issued by the International Law Commission's Study Group on this topic.

Georg Nolte is Professor of International Law at the Humboldt University in Berlin. He is a member of the UN's International Law Commission and the chair of the Commission's Study Group on Treaties over Time. He has published widely in the field of general international law, and he is one of the co-editors of our Commentary on the UN Charter (3rd edition, 2012).

1. Introduction
Part 1: Subsequent Practice Among the Different Means of Interpretation
2. Subsequent Agreements and Practice within the Vienna Convention, Luigi Crema
3. Keeping Subsequent Agreements and Practice in Their Right Limits, Marcelo G. Kohen
4. Subsequent Agreements and Practice from a Consensualist Perspective, James Crawford
5. Some Problems Arising in Connection with Subsequent Agreements and Practice, Bruno Simma
Part 2: The Significance of Subsequent Practice in Different Areas of International Law
6. Subsequent Practice, Practices and 'Family Resemblance': Towards Embedding Subsequent Practice in its Operative Milieu, Laurence Boisson de Chazournes
7. The Relevance of Subsequent Agreements and Practice for Treaty Law to Date and in the Future, Sean D. Murphy
8. Subsequent Practice: The Battle over Interpretive Power, Anthea Roberts
9. TBC, Campbell McLachlan
Part 3: Subsequent Practice Between Interpretation, Informal Modification, and Formal Amendment
10. Subsequent Agreements and Practice: Between Interpretation, Informal Modification, and Formal Amendment, Gerhard Hafner
11. Subsequent Practice Between Interpretation, Informal Modification, and Formal Amendment: A Comment, Jose E. Alvarez
12. Law, Time and Change: The Self-Regulatory Function of Subsequent Practice, Andrea Bianchi
Part 4: Subsequent Practice and the Domestic Level
13. Domestic Constitutional Concerns with Respect to the Use of Subsequent Agreements and Practice at the International Level, Stefan Kadelbach
14. Subsequent Agreements and Practice: Domestic Constitutions, Courts, and Legitimacy, Helene Ruiz Fabri
15. Treaty Interpretation, Subsequent Agreements and Practice, and Domestic Constitutions, Ingrid Wuerth
Part 5: ILC Study Group on Treaties Over Time
Introductory Report of the Study Group on Treaties over Time
Second Report of the ILC Study Group on Treaties over Time