International Law, International Relations and Compliance

Commitments are a persistent feature of international affairs. Disagreement over the effect of international commitments and the causes of compliance with them is equally persistent. Yet in the last decades the long-standing divide between those who believed that international rules per se shaped state behavior and those who saw such rules as epiphenomenal or insignificant has given way to a more nuanced and complex debate. The proliferation and evolution of international legal agreements, organizations, and judicial bodies in the wake of the Cold War has provided the empirical predicate and a policy imperative for heightened attention to the role of international law. Across many issue-areas, the use of law to structure world politics seems to be increasing. This phenomenon of legalization raises several questions. What factors explain the choice to create and use international law? If law is a tool or method to organize interaction, how does it work? Does the use of international law make a difference for how states or domestic actors behave? These questions are increasingly of interest to theorists and policymakers alike. This chapter surveys recent developments in the study of compliance in both the international relations (IR) and international law (IL) literature. Part one defines the concept of compliance, distinguishing it from the related but distinct concepts of implementation and effectiveness. We also focus primarily on compliance with treaties, rather than with the broader categories of rules that international lawyers term 'customary international law.' Part two reviews the major theories advanced by IR and IL scholars through the 1990s, setting forth a chronological account. Part three situates these theories in the context of a typology of six different variables that scholars from both disciplines have identified as influencing the existence and degree of compliance. Part four reviews a range of more recent empirical studies of compliance, as well as the results of cognate analyses of regime design, legalization, and the choice of hard law versus soft law. Part five concludes by identifying a number of open questions.