Redefining Imminence: The Use of Force Against Threats and Armed Attacks in the 21st Century

3 1. Introduction To put it simply, and, I fear, through a banality it may not deserve, the message is that there must be limits to the exercise of power … and that when professional men and women engage in an argument about what is lawful and what is not, they are engaged in a politics that imagines the possibility of a community … allowing a meaningful distinction between lawful constraint and the application of naked power. (Marti Koskenniemi, The Gentle Civilizer of Nations, p. 503) Drafted at the conclusion of the most destructive war in history, the UN Charter sought to prevent aggressive war by eliminating virtually all uses of force between States, save in cases of self-defence against an armed attack or under authorization of the Security Council when there was a clearly identified threat to international peace and security. Six decades later, however, inter-state wars are no longer the main threat to the stability of the international system. Rather, asymmetrical warfare, launched by international terrorist organizations and hostile governments holding weapons of mass destruction,1 has been widely recognized as today’s most serious security risk. This mismatch between the contemporary threat environment and international legal rules on the use of force generated a degree of scepticism among statesmen and scholars as to whether the existing international rules are still applicable to the rapidly changing security context. Indeed, the law governing recourse to military force in international relations remains fundamentally stable even in the 21st Century, but some challenges have been posed. One of the most complex and controversial is the call for a more permissive approach to the use of force in self-defence in international law allowing the doctrine to adapt to the specific character of the modern security threats. The US National Security Strategy,2 released in September 2002, reflects precisely this challenge, proposing, in effect, two ways of adapting the law to the new circumstances: the first is to reformulate the traditional standard of imminence that arguably enables States to strike first at an adversary that is about to attack; the second is to drop it altogether. 1 The phrase ‘hostile governments’ refers in this paper to governments with weapons of mass destruction that manifest certain hostile intent and/or support the activities of terrorist groups residing within their territories. 2 The National Security Strategy of the United States of America (17 September 2002), <http://www.whitehouse.gov/nsc/nss.pdf>.