Diffusion research often characterizes the role of the federal government in innovation adoption as a supportive one, either increasing the likelihood of adoption or its speed. We examine the adoption of medical marijuana laws (MMLs) from 1996 to 2014 to shed light on what motivates states to adopt innovations that are in explicit defiance of federal law. Furthermore, we examine whether federal signals have any influence on the likelihood of adoption. In doing so, we utilize implementation theory to expand our understanding of how the federal government's position impacts state policy innovation adoption. We find mixed evidence for the influence of federal signals on the adoption of MMLs. The results suggest that medical marijuana policies are much more likely to be adopted in states when proponents have the political or institutional capital, rather than a medical or fiscal need. Moreover, this political capital is sufficient independent of the federal government's real or perceived position.

A comparative approach to studying the spread of policy innovations has recently yielded new and interesting results, as well as theoretical advancements, for policy diffusion research. Specifically, punctuated equilibrium theory has been offered as an explanation for why some policies spread quickly, while others do so normally, and still others are adopted very slowly. Studies of adoption speed, however, currently rely on careful case selection or a dichotomous categorization of adoptions as fast or slow to test why policies diffuse at different speeds. Building on this foundational work, I propose a method for measuring adoption speed as a continuous concept, so that it can be modeled directly as an important outcome of interest to diffusion scholars. I then use the new measure to evaluate how adoption speed varies across time and policy domain. I further demonstrate the utility of the measure as a dependent variable by replicating past results, including the interactive effect of complexity and salience on adoption speed and positive effect of federal incentives, as well as finding preliminary evidence that policy clusters spread more rapidly than the average stand-alone policy.

Efforts to correct energy deficiency, which in turn may promote reproductive health, are warranted in order to address the unique contributions of energy status versus estrogen status to bone health.

States adopt policy innovations within the confines of a dynamic American federal system, but our study of policy diffusion tends to be fairly static. Single-policy studies incorporate temporal variation, but for only one innovation. Macro-level analyses examine broad patterns, but often by completely pooling across policy and time. This makes it difficult to identify how diffusion patterns change over time, though Walker's early work explicitly identified such temporal instability. This study specifically examines how neighbor and ideological cues change in importance over time using a dataset of 556 policies adopted from 1960 to 2014. While the findings demonstrate the generality of many key internal, external, and policy-level determinants of adoption, there is variation in these effects across time. Most important is the relative stability of ideological similarity between adopters and declining influence of contiguous neighbors. Further, political polarization plays a role in conditioning neighbor and ideological cues.

This essay discusses how scholarship on state politics and policy, intergovernmental relations, and federalism provides necessary context for understanding governmental responses to COVID-19. It also highlights how observing those responses can further push the bounds of existing scholarship and theory regarding policy innovation and cooperative and conflictual federalism. It argues that there is a space for mutual learning and sharing between scholars and practitioners.