Military Response to Terrorism and International Law on the Use of Force

In the post-Cold War security environment there have been factual developments and ambiguities that pose important challenges to the basic concepts, principles and rules of international law, especially concerning the use of force. The first part of this paper considers the option of multilateral employment of military force to prevent or to respond to acts of terrorism, and looks particularly at the Security Council's gradual enlargement of the notion of threat to international peace and security with respect to (international) terrorism. The second, and central, part of the paper then proceeds to examine the complex issue of a unilateral military response to terrorism, focusing on some its most murky features, such as: (a) the appropriate interpretation of the concept of ‘armed attack’ in the context of terrorist activities; (b) the requirement of attributability to States of terrorist attacks; and (c) the doctrines of anticipatory and preventive self-defence.