There has been considerable debate in the international community as to the legality of the forceful actions in Kosovo in 1999, Afghanistan in 2002 and Iraq in 2003 under the United Nations Charter. There has been consensus, however, that the use of force in all these situations had to be both proportional and necessary. Against the background of these recent armed conflicts, this 2004 book offers the first comprehensive assessment of the twin requirements of proportionality and necessity as legal restraints on the forceful actions of States. It also provides a much-needed examination of the relationship between proportionality in the law on the use of force and international humanitarian law.

"Necessity and proportionality occupy a firm place in the international law governing the use of force by states. Perhaps most importantly for practical purposes, the exercise of the right of self-defense, as recognized in Article 51 of the United Nations Charter, is subject to the requirements of necessity and proportionality, as the International Court of Justice determined in the Nicaragua case. Necessity and proportionality are also firmly anchored in the international law governing armed conflicts. In its Nuclear Weapons Advisory Opinion, the International Court of Justice even referred to one articulation of the idea of necessity, that directed against the causing of unnecessary suffering, as one of two "cardinal principles" of this body of law. However, beyond statement in such general terms, the realms of uncertainty and controversy soon begin. It is far from clear, for example, how to distinguish with precision between necessity and proportionality in the international law on self-defense and, in immediate connection herewith, what it means precisely to say that forcible action taken in the exercise of self-defense must be proportionate. It is all the less clear what legal significance, if any, necessity and proportionality possess in other contexts of the international law governing the use of force"--

States invariably justify using force extraterritorially by reference to their right of self-defence. In doing so, they accept that the exercise of this right is conditioned by the customary international law requirements of necessity and proportionality. However, these requirements are notorious for being normatively indeterminate and operationally complex. As a breach of either requirement renders ostensibly defensive action unlawful, increased determinacy regarding their scope and substance is crucial to how international law constrains military force. This book examines the conceptual meaning, content, and practical application of necessity and proportionality as they relate to the right of self-defence following the adoption of the UN Charter in 1945. It provides a coherent and up-to-date description of the applicable contemporary international law and proposes an analytical framework to guide its operation and appraisal. This book argues that necessity and proportionality are conceptually distinct and must be applied in the foregoing order to avoid an insufficient 'catch-all' description of legality or illegality. Necessity determines whether defensive force may be used to respond to an armed attack and where it must be directed. Proportionality governs how much total force is permissible and prohibits excessive responses. Both requirements are shown to apply on an ongoing basis throughout the duration of an armed conflict prompted by self-defence. Compliance with necessity and proportionality ensures that the purposes of self-defence are met, and nothing more, and that defensive force is not unduly disruptive to third party interests and to international peace and security.

In NATO Rules of Engagement, Camilla Guldahl Cooper offers clarity on a topic prone to confusion and misunderstanding. NATO rules of engagement (ROE) are of considerable political, strategic and operational importance, yet many of its concepts lack clarity. The resulting ambiguity may be detrimental for people involved and for mission accomplishment. Through a thorough analysis of the concept, purpose, development and use of NATO ROE, Cooper contributes to improved understanding and implementation of NATO ROE. The book covers all use of force categories and relevant law relating to the use of force during armed conflicts, including the complex concepts of hostile act and hostile intent, direct participation in hostilities, and the increasing reliance on self-defence during armed conflict.

The Use of Force and International Law offers an authoritative overview of international law governing the resort to force. Looking through the prism of the contemporary challenges that this area of international law faces, including technology, sovereignty, actors, compliance and enforcement, this book addresses key aspects of international law in this area: the general breadth and scope of the prohibition of force, what is meant by 'force', the use of force through the UN and regional organisations, the use of force in peacekeeping operations, the right of self-defence and the customary limitations upon this right, forcible intervention in civil conflicts, the controversial doctrine of humanitarian intervention. Suitable for advanced undergraduate and postgraduate students, academics and practitioners, The Use of Force and International Law offers a contemporary, comprehensive and accessible treatment of the subject.

Tallinn Manual 2.0 expands on the highly influential first edition by extending its coverage of the international law governing cyber operations to peacetime legal regimes. The product of a three-year follow-on project by a new group of twenty renowned international law experts, it addresses such topics as sovereignty, state responsibility, human rights, and the law of air, space, and the sea. Tallinn Manual 2.0 identifies 154 'black letter' rules governing cyber operations and provides extensive commentary on each rule. Although Tallinn Manual 2.0 represents the views of the experts in their personal capacity, the project benefitted from the unofficial input of many states and over fifty peer reviewers.

1. Introduction 2. What is Proportionality? 3. Proportionality: A Multiplicity of Meanings 4. Proportionality in the Just War Tradition 5. Proportionality in International Humanitarian Law 6. Proportionality in Human Rights Law and Morality 7. The Uniqueness of Jus in Bello Proportionality 8. Countermeasures and Counterinsurgency 9. Human Shields and Risk 10. Targeted Killings and Proportionality in Law: Two Models 11. The Nature of War and the Idea of "Cyberwar" 12. Thresholds of Jus in Bello Proportionality Bibliography Index.

Praise for previous edition: “...a comprehensive, meticulously-researched study of contemporary international law governing the use of armed force in international relations...' Andrew Garwood-Gowers, Queensland University of Technology Law Review, Volume 12(2) When this first English language edition of The Law Against War published it quickly established itself as a classic. Detailed, analytically rigorous and comprehensive, it provided an indispensable guide to the legal framework regulating the use of force. Now a decade on the much anticipated new edition brings the work up to date. It looks at new precedents arising from the Arab Spring; the struggle against the "Islamic State" in Iraq and Syria; and the conflicts in Ukraine and Yemen. It also reflects the new doctrinal debates surrounding recent state practice. Previous positions are reconsidered and in some cases revised, notably the question of consensual intervention and the very definition of force, particularly, to accommodate targeted extrajudicial executions and cyber-operations. Finally, the new edition provides detailed coverage of the concept of self-defense, reflecting recent interpretations of the International Court of Justice and the ongoing controversies surrounding its definition and interpretation.

This book examines to what extent the right of self-defence, as laid down in Article 51 of the Charter of the United Nations, permits States to launch military operations against other States. In particular, it focuses on the occurrence of an 'armed attack' - the crucial trigger for the activation of this right. In light of the developments since 9/11, the author analyses relevant physical and verbal customary practice, ranging from the 1974 Definition of Aggression to recent incidents such as the 2001 US intervention in Afghanistan and the 2006 Israeli intervention in Lebanon. The notion of 'armed attack' is examined from a threefold perspective. What acts can be regarded as an 'armed attack'? When can an 'armed attack' be considered to take place? And from whom must an 'armed attack' emanate? By way of conclusion, the different findings are brought together in a draft 'Definition of Armed Attack'.

Berenika Drazewska’s book offers a comprehensive scholarly analysis of the current meaning of military necessity in the international legal framework for the protection of cultural heritage during armed conflicts.