Necessity and Proportionality in International Peace and Security Law

Abstract

Abstract Necessity and proportionality hold a place in the international law governing the use of force by states and in the law of armed conflict (LOAC). However, the precise contours of these two requirements are uncertain and controversial. This book explores in 5 parts how necessity and proportionality manifest under the law governing the use of force and the LOAC. First, the book introduces the reader to how necessity and proportionality factor in the debate about the interaction between morality and law in the use of military force. Second, the book addresses the issue of how proportionality in the law governing the use of force relates to proportionality in the LOAC. Third, the book addresses a number of pressing legal issues including: how proportionality and necessity are linked under international law, the controversial “unwilling and unable” test, drones and targeted killing, their application during civil war, and the need for further transparency in states’ justification for the use of force in self-defense. Fourth, the book analyzes the role of military necessity within the LOAC on the battlefield. This includes discussions about 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 a proportionality analysis. Finally, the book concludes with a discussion on the potential role of proportionality in the law governing post-conflict contexts.