Intergovernmental Policy Diffusion: National Influence on State Policy Adoptions Pamela Clouser McCann University of Michigan Charles R. Shipan University of Michigan Craig Volden The Ohio State University April 7, 2010 Paper prepared for the 2010 Midwest Political Science Association Meeting. ABSTRACT: National political institutions, such as Congress and the president, can influence state-level policymaking by adopting laws that specifically direct the states to take certain actions, or by providing financial incentives to take certain actions. But can these national institutions also influence state-level adoptions by drawing attention to an issue, and by providing information about it, even when these activities do not produce laws? In other words, do policy ideas diffuse from the national government to the states? In this paper we explore the influence of national policymaking activities on state-level adoptions. More specifically, we examine whether hearings and the introduction of bills in Congress stimulate state level adoptions. Furthermore, we examine whether this effect varies systematically according to characteristics of the state, and also investigate whether national activities affect state-to-state policy diffusion. Our findings reveal some support for the idea that national policymaking activities influence state-level adoptions.