International regimes are continuous two-dimensional negotiations for the purpose of resolving a problem of coordination under uncertainty among sovereign states. This characterization contains a number of important propositions, some pointing out new aspects of regimes and others taking a position in the ongoing debate on the subject, while at the same time building on many aspects of the work already done on regimes. The main thrust of this work is to correct the “one-time” image of regimes as something that is decided through a process but that then remains relatively fixed, inviting analysis of ratification, compliance, and effectiveness. It is a profound misunderstanding of the regime-building process to believe that it is merely a matter of legislation and compliance. Regimebuilding is ongoing negotiation.