Policy Innovation and Diffusion Through Policy Typologies

In recent years, the legalization of medical marijuana in states has been a controversial topic. Despite conflicting with the federal government ban on marijuana use, 28 states and D.C. have legalized medical marijuana by the year 2016 and other states are currently considering adopting the law every year. Why do some states adopt medical marijuana laws and others do not? This study lays out an approach that explains what and how the predictors of the adoption of medical marijuana laws affect legalizing medical marijuana in a state, using a mixed methods approach. In the quantitative research, this study examines the diffusion of medical marijuana laws by analyzing policy adoption from a morality and economic development perspective through three policy typologies such as morality policy, economic policy and multidimensional policy. For the qualitative research, this study uses short case studies of three states (California, Colorado, and Illinois) based on news reports to draw out the politics surrounding the issues and reasons why the policies were adopted. This study finds that the morality policy characteristics as policy diffusion factors -- religious groups, citizens’ liberal ideology, and a ballot initiative process -- have a significant effect on the adoption of a medical marijuana law. Economic indicators -- fiscal capacity growth, incarceration, and cost of justice system -- also have a significant effect on the adoption. As internal characteristics, a major proponent group (number of marijuana users) and state regulatory environment (mandatory minimum sentences for drug offenses and the size of the regulatory bureaucracy) are important predictors of diffusion. Overall, this study shows that the diffusion of a medical marijuana law is mainly determined by the citizens’ opinion rather than elected officials’ political ideology or government's fiscal health conditions. Also, we demonstrated that a multidimensional policy model provides a superior explanation for predicting when a state will adopt medical marijuana policy; policy typologies are still a useful framework for clarifying and understanding characteristics of each policy type and its unique politics pattern. These findings contribute to the literature of diffusion, and they have important implications for the diffusion of multidimensional policies that transcend classical typological boundaries. Moreover, in terms of practical implication, this study provides policy makers and American civil society useful information about which factors impact medical marijuana adoption and why.