Mercury Rising: How State Policy Diffusion Influences National Public Opinion

<p>This dissertation examines the relationship between state policy diffusion and related national public opinion over time. Specifically, I ask whether state-level policy activity can influence national opinion where a policy diffuses sufficiently to encompass a majority of citizens. Although scholars have identified the linkage between policy activity and public opinion at the national level and within the states, the dynamics of this relationship <i>across</i> levels within the American federal system remain largely unexplored. Consequently, our understanding of public opinion on a host of issues in politics – such as gay marriage, abortion, crime policy, and gun control – remains incomplete. There is reason to suspect, however, that where issues are acted upon at the national <i>and</i> subnational levels, related opinion is influenced by the policy activities of both systems. In this dissertation, I offer a new dynamic underlying public opinion change in the United States, the <i>diffusion-opinion-linkage</i>, which reveals the influence of state policy diffusion on related national opinion over time. I analyze this relationship by leveraging temporal and geographic variation in the passage of “shall-issue” concealed carry laws in the states from 1990-2010. I assess the effects of shall-issue debate, passage, and policy feedback on individual attitudes, state-level opinion, and national measures, finding a clear relationship between the diffusion of this policy and growing national gun policy conservatism over time. I conclude by discussing how this study contributes to the public opinion and diffusion literatures, with a recommendation that the individual and collective dynamics of the <i>diffusion-opinion-linkage</i> be considered when evaluating the connection between policy activity and public opinion in future work.</p>