© 2004 by British Institute for International and Comparative Law
Terrorism and International Law
1 Judge and former President of the International Court of Justice
Terrorism traditionally meant ‘terror organized by a State’ before becoming ‘terror directed against a State’. Its development during the second half of the twentieth century prompted States, starting in 1963, to marshall international cooperation with a view to preventing and condemning this type of criminal act. For a long time States did so without using the word ‘terrorism’ as such. However, under pressure from politicians, the media and NGOs, the word ‘terrorism’ began appearing in international conventions and United Nations resolutions — mostly without being defined. Things did not change significantly following the events of 11 September 2001, which did, however, trigger a new determination to ensure the universal application of existing measures. In this respect, they led the Security Council to play a truly legislative role.
Action taken against States participating in acts of terrorism also developed: when dealing with such wrongful acts, States relied sometimes on the law of State responsibility. But they also resorted to various forms of pressure, ranging from counter-measures to the use of armed force. In this context, the action taken by the United States and its allies in Afghanistan after 11 September 2001 raised a number of highly sensitive issues regarding selfdefence and the treatment of prisoners held in Guantanamo.
Overall, these events have propelled States to the forefront of the international arena. They represent the best defence against terror. But States must act in conformity with international law. That is the underlying condition for the legitimacy of their action.