1 Social Norms2.0. Word-count: 11,602.

Social norms, defined as shared expectations about appropriate behavior, are ubiquitous in world politics. Regulatory norms, which prescribe appropriate behavior for state and non-state actors, exist in a variety of issue-areas. Yet these regulatory norms are so closely linked to interests, and so frequently conflict with one another, that the causal impact of norms is often ambiguous. In world politics, norms need advocates, but it is difficult to disentangle the effects of advocacy and interests from those of the norms themselves. The weakness of customary international law, which lacks clear agency, reinforces the conclusion that the significance of regulatory social norms in world politics depends on strategic agents whose interests, whether shaped by norms or not, impel them toward promoting the norms. Acknowledgements: I thank Peter J. Katzenstein and Charles Beitz for helpful comments on earlier versions of thi