This chapter firstly contends that in Oakeshott's political philosophy there are considerations pertaining to the evolution of the international order based on the theory of civil association. In particular, these observations concern war, colonialism, and the evolution of international society. Secondly, the chapter explores and defends the notion of practical association as first presented by Terry Nardin. In particular, it contends that international society may be considered as an association between states constituted by a set of non-instrumental rules that reflect shared moral values, values that represent the shared premises of institutional moral reasoning. Finally, the chapter shows that this approach illuminates the normative nature of customary international law and its relations with international morality.