The chapter examines the role of the UN Charter in shaping the Cold War’s ideological and legal landscape. The chapter begins with Winston Churchill’s 1946 ‘Sinews of Peace’ speech, which highlighted the duality of the post-war world: the creation of the United Nations and the emerging division between East and West. The UN Charter, while promoting sovereign statehood and universality, also formalised the Amero-Soviet rivalry, embedding ambiguities that allowed ideological contestation within a lawful framework. The Charter’s emphasis on sovereign statehood and the nation-state form provided a template for decolonisation, yet left space for rival interpretations and political agendas, particularly from Latin American, African and Asian states. The chapter explores how the Charter’s ambiguities facilitated US–Soviet competition, focusing on representation, intervention and self-determination. It highlights the Charter’s role in enabling covert US–Soviet rivalry and its impact on global order, decolonisation and the stabilisation of property ownership. The chapter concludes by setting the stage for the next chapter, which will explore the Amero-Soviet project of world-making through the UN Charter and its broader geopolitical implications.