The attack on the World Trade Center and the Pentagon on 11 September 2001 brought a revolutionary challenge to the doctrine of self-defence and its reassessment of the law in this area (Gray 2004, 940). This comment by Gray was made in light of the fact that although use of force in response to terrorist attacks on nationals abroad was already a contentious debate, it only attracted claims from Israel and the USA in declaring and exercising the right.
The topic “Use of Force” in International Law can be described as litigious. Issues surrounding the Use of Force in International Law have fired much debate since the official law was established in 1945 in the United Nations Charter. Much of this debate stems from people’s theoretical perspectives and explanations of how the international system is, or ought to be. If we examine the two original theories of International Relations we can note that the realists believe in military power being more important than economics and that war is necessary as it keeps a balance in the world order. On the other hand, the liberalists hold that reason and ethics can overcome international anarchy to create a more orderly and cooperative world.
Before 1945, the relation of war to the international system was stated by W.W. Hall in a well-known passage which stated “International law has no alternative but to accept war, independently of the justice of its origin, as a relation which the parties to it may set up if they choose, and to busy itself only in regulating the effects of the relation.” (Hall 1924, 82)
After 1945, the law regarding use of force had changed tremendously. The Charter of the United Nations was signed on 26 June 1945, in San Francisco, at the conclusion of the United Nations Conference on International Organization,