This chapter discusses compliance and soft law, followed by a review of perspectives from comparative politics and international relations regarding what makes individual states choose to comply with soft law instruments. The book appears to mean two things by 'soft law'. One is a process of establishing authoritative judgments and establishing collective aspirations. The second is a set of public commitments which lack clear mechanisms for enforcement. The chapter argues that compliance is a matter of state choice, and that that choice is often subject to institutional and constructivist forces. While there may be more compliance than skeptics believe, there is also probably less than many international lawyers and international relations scholars would prefer. Finally, the chapter considers the possibility that exposure to withdrawned international inducements over time may lead to new habits on the part of states, and that they would comply even with the removal of institutional incentives to comply.