In Chapter 3, it was demonstrated that the weakness of the League Covenant’s concept of aggression as a moral trigger for collective security action led to efforts by members to define aggression, with a view to creating an unambiguous, legally proscribed act. In the end, however, no consensus on a definition of aggression emerged, and the League was eventually destroyed by the onset of World War II. Despite this early lack of success – and Wilson’s prior rejection of legal approaches to aggression – from the 1940s onward the idea re-emerged of making more precise through legal definition what state aggression comprises. Attempts towards this goal were made over a thirty-year period; yet three separate political struggles prevented any progress from being made. The first struggle, which took place during the UN Charter negotiations, existed initially among the great powers, all of whom sought to promote a new international security organisation in their own, individual self-interests. From the initial plans discussed among the great powers, it is evident that they were divided on the role of aggression. Once the broad outline of the new organisation had been thrashed out among the great powers, a second struggle emerged, this time between the great powers collectively on the one hand and the small and middle powers on the other. The great powers’ division over aggression was resurrected, with the small and middle powers pushing for a definition of aggression to be included in the founding document of the new organisation as a way of subjecting the great powers to the force of law, both compelling and limiting their actions. Although the small and middle powers lost this battle, the issue of defining aggression continued in the post-Charter period. While UN committees consistently approached the problem of aggression as simply a question of legal definition, the disputes played out in these committees reflected a third political struggle: the Cold War conflict between the USA and the Soviet Union, as well as their respective allies. Once again, it is revealed in this chapter that the narrow self-interest of states acts as a significant constraint on broader cosmopolitan goals such as the further development of international law. This chapter shows this to be true even in relation to those basic values which attract universal condemnation, such as aggression. Thus, the significance of favourable political conditions as a necessary foundation for cosmopolitan progress cannot be underestimated. Before examining attempts to define aggression in the UN period, it is important first to understand

how the notion came to be included in the UN Charter, particularly after the controversy it generated in relation to the League.