Global action and regulation is increasingly the result of the interplay between formality and informality. From the management of State conduct in international security to the coordination of national policies in climate change, international organizations work ever closer with coalitions of the willing. This book carefully describes this dynamic game, showing that it consists of transformative orchestration strategies and quasi-formalization processes. On the institutional plane, coalitions of the willing turn into 'durable efforts', while international organizations perform as 'platforms' within broader regime complexes. On the normative level, informal standards are framed in legal language and bestowed with the force of law, while legal norms are attached to multilayered schemes of implementation, characterized by pragmatic correspondences, persuasion tactics, and conceptual framing. Understanding how this interplay alters the notion of 'international legality' is crucial for the necessary recalibrations of the political ideals that will inform the rule of law in global governance. 'It has by now become clear that the world’s two major powers - a declining hegemon as well as an emerging one - are poised to shun multilateral international organizations and instead are experimenting with various types of 'coalitions of the willing'. Rodiles offers a comprehensive theoretical and historical analysis of this strategy and demonstrates its benefits for those powers who lead them, such as the US and China, as well as its costs for all the rest and for the ideals of inclusive multilateralism and the rule of law. His sensitive and convincing account is crucial for understanding the contemporary trajectories of international law and politics.' Eyal Benvenisti, University of Cambridge An analysis of the role of the interplay between formality and informality in shaping the current state of international law. Alejandro Rodiles is an Associate Professor of International Law at Instituto Tecnológico Autónomo de México, Mexico City. He undertook his doctoral studies at Humboldt-Universität zu Berlin and is a member of the International Law Association's study groups on UN sanctions, and on cities and international law. In addition to his academic pursuits, he has extensive diplomatic experience, including as legal advisor of Mexico's Mission to the United Nations, as sous-sherpa to the Nuclear Security Summit, at the Office of the Legal Advisor, and at the Policy Planning Staff of the Foreign Minister.