ABSTRACT
This chapter traverses the developments that occurred in relation to the ius ad bellum in the inter-war period, from the formation of the League of Nations in 1919 until 1944, immediately prior to the formation of the United Nations. This period witnessed a gradual progression from attempts at preventing war to prohibiting war outright, via binding, multilateral treaties as well as bilateral, arbitration and non-aggression agreements. The League of Nations Covenant was a major development in the limitation of the resort to war by states. It was a major turning point in the development of international law relating to the recourse to force because, by virtue of its procedures for the pacific settlement of disputes, it created a clear legal distinction between legal and illegal wars. The chapter explains the law regarding the resort to force by states, as it stood immediately prior to the adoption of the UN Charter.
