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.

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 necessary and proportional. Against the background of these recent armed conflicts, this book offers the first comprehensive assessment of the twin requirements of necessity and proportionality 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 hold a firm place in the international law governing the use of force by states, as well as in the law of armed conflict. However, the precise contours of these two requirements are uncertain and controversial. The aim of Necessity and Proportionality in International Peace and Security Law is to explore how necessity and proportionality manifest themselves in the modern world under the law governing the use of force and the law of armed conflict, and how they relate to each other. The book explores the ways in which necessity and proportionality are applied in practice and addresses pressing legal issues in the law on the use of force, including the controversial "unwilling and unable" test for the use of force in self-defense, drones and targeted killing, the application of this legal regime during civil war, and the need for further transparency in states' justification for the use of force in self-defense. The analysis of the role of military necessity within the law of armed conflict on the modern battlefield focuses on the history and nature of the principle of military necessity, the proper application of the principle of proportionality, how commanders should account for mental harm in calculating proportionality, and the role artificial intelligence and autonomous weapons systems may play in proportionality analysis. The book concludes with a discussion of the potential role of proportionality in the law governing post-conflict contexts.

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.

The book examines in detail one of the most controversial topic in current international law, namely the scope and extent of the right of individual self-defense. The book carefully traces the paths which have been followed in the developing legal debate on self-defense. The author uses numerous case-studies of incidents involving the use of force in alleged self-defense (such as the Entebbe Incident 1976, the Nicaragua Case 1986 or the Israeli-Lebanese conflict of 2006) which have formed the central point of scholarly debate. The author's conclusions are based not only on thorough analysis of academic discussions but also of the practice of States and international bodies, especially of the United Nations Organization. At the outset of the book the author reviews the historical context and the customary evolution of the right of self-defense. Reference is made to the famous Caroline Case of 1837, which set the necessary conditions of lawful exercise of self-defense. Next, the author examines the concept and legal nature of self-defense, carefully assessing the customary conditions of necessity, proportionality and immediacy derived from the Caroline Case. As the occurrence of an "armed attack" is a conditio sine qua non of lawful invocation of self-defense, several modalities of an armed attack are attentively evaluated such as its constituent elements, beginning or scale. The author explores, whether reactions to acts of international terrorism committed by a non-State may be based on the right of self-defense. In times of global terrorist networks it is highly desirable to attach special attention to use of force in self-defense as a remedy against serious acts of terrorism. Thorough analysis of State practice is shown on several examples from recent history - the U.S. air raid on Libya in 1986 and on Baghdad in 1993 and relatively recent air strikes on Sudan and Afghanistan in 1998. Reference is also made to the most striking example - the Al-Qaeda attack on the United States in 2001. The validity of claims of anticipatory/preventive self-defense is examined on a theoretical level and then applied to the specific details of the Israeli air strike on the Osiraq Nuclear Reactor in 1981. The two main approaches to preventive self-defense - "restrictive" and "traditional" - are then discussed in detail. Brief analysis is also devoted to the nature of the so-called - pre-emptive - self-defense indicating its current position under international law.

Determining the earliest point in time at which international law authorises a state to exercise its inherent right of self-defence is an issue which has been debated, but unsatisfactorily reasoned, by scholars and states since the 1960’s. Yet it remains arguably the most pressing question of law that faces the international community. This book unravels the legal and factual complications which have obscured the answer to this question. In contrast to most other works, it takes an historic approach by tracing the evolution of the rights, rules and principles of international law which have governed the use of force by states since the 16th century. Its emphasis on self-defence provides the reader with a new and complete understanding of how and why the international legal framework limits defensive force to repelling an imminent threat or use of offensive force which is directed at the territory of a state. Taking an historic approach enables this book to resurrect an understanding of the human defensive instinct which has guided the formation of the international law of self-defence. It also explains the true legal nature and scope of the inherent right of self-defence, of anticipatory self-defence and provides a definition of the legal commencement of an armed attack for the purpose of Article 51 of the Charter. Finally, the reader will receive a unique source of research materials and analysis of state practice and of scholarly works concerning self-defence and the use of force since the 16th century, which is suitable for all readers of international law around the world.

By any measure, Judith Gardam has accomplished much in her professional life and is rightly acknowledged by scholars throughout the world as an expert in her many fields of diverse interest — including international law, energy law and feminist theory. This book celebrates her academic life and work with twelve essays from leading scholars in Gardam’s fields of expertise.

The right of States to use force extraterritorially is conditioned by requirements of necessity and proportionality. This book provides a much-needed detailed analysis of those requirements, and a coherent and up-to-date account of the applicable contemporary international law in this field.

This book explores the large and controversial subject of the use of force in international law. It examines not only the use of force by states but also the role of the UN in peacekeeping and enforcement action, and the increasing role of regional organizations in the maintenance of international peace and security. The UN Charter framework is under challenge. Russia's invasion of Georgia and intervention in Ukraine, the USA's military operations in Syria, and Saudi Arabia's campaign to restore the government of Yemen by force all raise questions about the law on intervention. The 'war on terror' that began after the 9/11 terrorist attacks on the USA has not been won. It has spread far beyond Afghanistan: it has led to targeted killings in Pakistan, Somalia, and Yemen, and to intervention against ISIS in Iraq and Syria. Is there an expanding right of self-defence against non-state actors? Is the use of force effective? The development of nuclear weapons by North Korea has reignited discussion about the legality of pre-emptive self-defence. The NATO-led operation in Libya increased hopes for the implementation of 'responsibility to protect', but it also provoked criticism for exceeding the Security Council's authorization of force because its outcome was regime change. UN peacekeeping faces new challenges, especially with regard to the protection of civilians, and UN forces have been given revolutionary mandates in several African states. But the 2015 report Uniting Our Strengths reaffirmed that UN peacekeeping is not suited to counter-terrorism or enforcement operations; the UN should turn to regional organizations such as the African Union as first responders in situations of ongoing armed conflict.