Extraterritorial Use of Force against Non-State Actors

This study assesses the rules of international law relevant to the use of force against non-State actors. The rules of international law on the use of force are the lynchpin of the project of international law for a more secure and peaceful world. Yet, as important as they are, the rules of international law on the use of force are also highly contentious. With the shift in the nature of conflicts from inter-State wars to conflicts involving non-State actors, and with the growth in the threat of global terrorism, the focus of the law on the use of force has shifted to the use of force against non-State actors. To assess the permissibility of the use of force against non-State actors, this study will focus on two grounds that have been advanced as bases for the extraterritorial use of force against non-State actors: the right of a State to act in self-defence and intervention by invitation. While there are other grounds that have been advanced for the extraterritorial use of force in international law, it is only in respect of these two grounds that the role of non-State actors has a significant influence on the legality or not of the use of force.

Table of Contents:
Prologue ........................ 13 Chapter I. The issues................. 14 A. Introduction................... 14 B. Policy considerations.............. 18 C. Outline ..................... 22 Chapter II. The prohibition on the extraterritorial use of force: the nuts and bolts and the methodology of international law.............. 24 A. Introduction................... 24 B. The methodological issues ........... 25 1. General.................... 25 2. The methodology for the identification of rules ..................... 27 (a) The methodology of treaty and custo mary international law ......... 27 (b) Peremptory status of the prohibition on the use of force ............. 35 C. The context of the prohibition on the use of force ....................... 46 1. Point of departure .............. 46 2. Collective security.............. 51 D. A survey of exceptions............. 58 Chapter III. Self-defence against non-state actors: the expansive approach .............. 62 A. Introduction................... 62 B. The extraterritorial use of force in self defence: A brief description .......... 64 C. The emergence of the permissive approach to self-defence against non-State actors .... 67 1. General.................... 67 2. The sources of support for the emergent permissive trend ............... 69 (a) The Chatham House Principles .... 72 (b) The Leiden Recommendations ..... 73 (c) The Bethlehem Principles ....... 75 (d) Authority for the propositions advanced in the policy instruments.... 77 D. The argument for an expanded approach ... 79 1. Literal reading of Article 51 ........ 79 2. Pre-existing customary international law. . 81 3. Contemporary State practice ........ 83 E. Concluding remarks .............. 94 Chapter IV. Evaluating the arguments for an expansive view of the extraterritorial use of force against non-state actors ........... 96 A. Introduction................... 96 B. The language of Article 51 .......... 98 1. The “inherent right” to self-defence .... 98 2. The meaning of the phrase “armed attack” 102 (a) “Armed attack” in the jurisprudence of the International Court of Justice ... 103 (b) Interpretation according to the Vienna Convention ............... 117 C. Other means of interpretation relevant to the meaning of “armed attack”........... 124 1. General practice ............... 125 2. 9/11-related practice............. 130 3. ISIS-related practice............. 136 4. Other rules of international law ...... 142 D. The level of attribution............. 143 Chapter V. Extraterritorial use of force against non state actors upon the invitation of the territorial state ......................... 146 A. Introduction................... 146 B. Intervention by invitation against non-State actors ...................... 148 1. Definitional issues.............. 148 2. Intervention by invitation and the prohibi tion on the use of force ........... 151 3. Limitation on intervention by invitation . . 157 4. Examples from modern practice on the application of these principles ....... 168 C. Conclusion ................... 177 Chapter VI. Concluding words ........... 181 A. Synopsis .................... 181 B. Between the restrictive and expansive approaches ................... 183 1. Self-defence against non-state actors: res trictive approach............... 183 2. Intervention by invitation against non-state actors: expansive approach ......... 185 C. Why the discrepancy? ............. 186 About the Author ................... 187 Biographical note.................. 187 Principal publications ............... 187