ABSTRACT
International law prohibits the threat of, and the use of, force in international relations. This principle which has acquired the status of ius cogens has developed over many centuries. These developments and their effects are examined in this chapter. The prohibition is not, however, absolute. The UN Charter itself recognises the right to selfdefence. Other exceptions, outside the UN Charter, have been established under international law-for example, the use of force by people in the exercise of their right to self-determination. Furthermore, states have invoked a number of justifications for the use of force, some of which have gone unchallenged by the international community. This constitutes a strong presumption in favour of their legitimacy.
