Terrorism and the international law on the use of force

The chapter addresses the use of force against terrorists abroad. The use of force against non-state actors may be authorized by the UN Security Council. More controversial is the use of force against terrorists in self-defence. Reliance is sometimes placed on the ‘unable and unwilling test’ and on ‘anticipatory self-defence’; neither is (yet) accepted by states generally. It is submitted that the existing rules of international law on the use of force are adequate (and anyway are not going to change anytime soon). What is needed is a greater degree of common understanding among states as to the application of the jus ad bellum in the face of modern terrorist threats.