This chapter takes the frames involved in the conceptual metaphor coalition of the willing, and the ideas transmitted by these frames. In identifying the different instances where coalitions of the willing have played an important role, a genealogy of the catchphrase is traced, sketching an account of the distinct usages the term has experienced in international political and legal discourses. Special attention is thus paid to the legal doctrines related to coalitions of willing and able States acting in the framework or at the margins of collective security, i.e. the multinational forces authorized and unauthorized by the UN Security Council to use all necessary means to maintain or restore international peace and security. It then shows how the notion of ‘coalition of the willing and able States’ that emerged in the 1991/1992 Gulf War was further elaborated and refined as part of a US foreign policy and global governance strategy, but which has been appropriated by other States, mainly powerful ones and beyond the West. It shows that common to these evolving notions is the challenge to organized multilateralism centred on the UN and international law.