The Political Structure of Policy Diffusion

Unlike the U.S. Constitution, many state constitutions include provisions for regulating and legislating specific policy issues. Embedding policy proscriptions in state constitutions may impact the rate and likelihood of policy diffusion. To examine how the amendment process influences diffusion resulting from geographic competition, we estimate a well‐known policy diffusion model, using state‐sponsored lotteries as a case study. Our mixed model of survival analysis separately estimates amendments and lottery adoptions allowing for different covariates and baseline hazards in each model. We find that there are different diffusion effects for constitutional amendments and policy adoptions, that the two‐step process requires a more professionalized legislature, and that amending the state constitution influences the timing of the adoption process. Once we take into consideration the two‐step process of lottery diffusion, we find a conditional diffusion effect that is over twice as large as previous estimates, and an overall diffusion that is larger than estimates from event‐history estimation, suggesting that the constitutional hurdle is an important determinant of policy adoption. These effects occur over the entire policy adoption phase (1961–2009), over multiple specifications of the baseline hazard, for alternate measures of diffusion, and for alternate model specifications, thereby suggesting that the constitutional hurdle is an important element of state policy, and it should be empirically considered in future models of policy diffusion.