Self-Defence and Collective Security

Abstract This chapter examines the distinction between self-defence and collective security, the two principal exceptions to the prohibition of the use of force in international law. The exercise of the right of self-defence, which includes collective self-defence, is recognized by Article 51 of the UN Charter, while collective security measures are authorized by the UN Security Council under Chapter VII of the Charter. Drawing on an article by Derek Bowett published in 1994, the chapter considers the academic debate and confusion in 1990–1 concerning the distinction between self-defence and collective security. In particular, it looks at the controversy regarding the legal basis of the use of force over Korea in 1950. It also outlines six differences identified by Bowett with regard to collective self-defence and collective measures under Chapter VII.