ABSTRACT
One of the most important, and consequently, most controversial subjects in public international law is the use of armed force. The use of force predominantly refers to military force; that is, where one or more State or international organisation uses military force against another State(s) or international organisation(s). Colloquially, the use of force refers to a State’s permissibility to go to war (also known as ‘armed conflict’ or ‘armed force’), and the laws governing the use of force are those which regulate when and under what conditions a State may (legally) go to war. Crucial to the rules on the use of force are the scope and extent to which it is prohibited. This chapter examines the prohibition of the use of force found in article 2(4) of the UN Charter and considers some of the exceptions to the prohibition. These include the right of individual and collective self-defence, UN Security Council authorisation, military assistance on request, humanitarian intervention, and the responsibility to protect. In so doing, the chapter provides an outline of the prohibition and regulation of resort to armed force in international law.
