Diffusion dynamics result not only from differences in the attributes of the innovation, but also from variations in the internal characteristics of those states encountering, responding to, and adopting new public policies. That state regulatory, morality, and governance policies each produce different patterns of policy diffusion revives a series of interesting questions regarding the diffusion of policy innovations in American states. What explains state receptivity to innovation? Why are some states receptive to innovation though others appear policy-resistant? Are states equally responsive across types of public policy, or does state receptivity to innovation shift depending on the characteristics of the agent of innovation?

The diffusion dynamics identified in Chapter 3 suggest the interesting possibility that state receptivity to innovation changes in response to the characteristics of policy innovation. Just as epidemiologists have discovered that populations with certain genetic or behavioral traits suffer from elevated risks for contracting a particular disease, states with particular political, economic, or ideological attributes are especially receptive to different classes of innovation. This expectation matches common explanations for variation in state policy making. For example, states with the initiative process are responsive to innovations that regulate the behavior of elected government officials, as they have the institutional means available to pursue governance reforms (Tolbert 2002). Religious and ideologically conservative states are more responsive to morality policies that regulate behaviors deemed “socially deviant” (Haider-Markel 2001).