The model includes a linear time variable to account for broader trends like growth in lobbying from distributed solar. I estimate multilevel models with random effects at the firm, state, and year levels to account for the hierarchical structure of the data. In column of Table 2, the outcome variable is a binary measure of whether a firm lobbied in a particular state-year .In column , the outcome variable is the total number of lobbying registrations attributed to a particular firm . For this specification, I estimate a negative binomial model since the outcome is an over dispersed count variable . Finally, in column , the outcome is logged lobbying expenditures for the limited sample of states for which these data are available. Across specifications, results, presented in Table 2, indicate that firm lobbying in a state is increasing in its installed TPO capacity in that state and its installed capacity in other states . The coefficients in column indicate that a doubling of in-state capacity is associated with an 8-percentage point increase in the likelihood of an installer lobbying, while a doubling of out-of-state capacity is associated with a 5-percentage point increase likelihood of an installer lobbying in any particular state. Results from the negative binomial model also indicate that both in-state and out-of-state capacity matter for lobbying. The coefficient of .47 in column suggests that a 1 percent increase in in-state capacity installed for a firm is associated with a .47 percent increase in number of retained lobbyists in that state ; the coefficient of .48 indicates that a 1 percent increase in out-of-state capacity is associated with a .48 percent increase in number of retained lobbyists in a given state . I recover consistent results in the limited sample of states using logged lobbying expenditures as the outcome in a linear model. The coefficients suggest that a doubling of in-state capacity is associated with a 71 percent increase in lobbying expenditures,hydroponic shelf system while a doubling of out-of-state capacity is associated with an 85 percent increase in lobbying expenditures in any particular state.

By showing that firm lobbying in any particular state depends on firm economic strength both within that state and across the states, these findings also suggests that policy in one state affects lobbying in another. That’s because state policy affects installer business growth , which in turn drives installer lobbying across the states due to the horizontal mobilization of firms. A particularly important case of cross-state feedback is where firms apply growth in states with favorable policy environments to seek to shape policy in potential new markets. To examine this dynamic, I track the economic and political presence across the states over time for the two largest and most politically active rooftop solar firms over the period: Sunrun and SolarCity. As illustrated by Table 3, both firms significantly expanded their political and economic presence from 2014 to 2016. While there is certainly significant overlap in the states where the firms were economically and politically active, both firms hired lobbyists in a number of states in which they were not selling systems. In 2016, for instance, SolarCity lobbied in 10 states in which it was not actively selling systems; Sunrun lobbied in 11 states where it did not have an economic presence. In many cases, these firms hired lobbyists in advance of economic expansion to particular states . To summarize, I have shown that: 1) favorable rooftop solar policy leads to rooftop solar industry growth, 2) rooftop solar industry growth leads to greater lobbying from rooftop solar industry both in the states where growth takes place as well as in other states, 3) rooftop solar firms have in a number of cases sought to influence policy in states where they are not yet active, and 4) installer lobbying is associated with more favorable policy, particularly in places where the industry has less of an economic presence. Taken together, the empirical analyses trace out a causal process whereby adoption of favorable rooftop solar policies in leading states affected the interest group politics—and ultimately policy decisions—in other states. Of course, the empirical analysis is not without its limitations. In particular, establishing causal inference in policy feedback and interest group influence research is a major challenge . In this case, neither policy enactment nor interest group lobbying is randomly assigned, nor are there apparent natural experiments to leverage.

Yet, by bringing together a multitude of both state- and firm-level data, this paper provides evidence in support of the proposed theoretical framework, and an empirical setup on which scholars working across different policy areas can build. In addition, the evidence presented does not rule out that traditional diffusion mechanisms of learning and competition have also shaped state-level rooftop solar policy and politics. It clearly demonstrates, however, that these traditional mechanisms are not the whole story. An analysis of interdependent policy making in this case that failed to consider the effects of state policies on the resources installers had at their disposal to engage politically in other states would be incomplete. Moreover, it is likely that the dynamics of cross-state policy feedback on interest group politics studied here can also serve to facilitate mechanisms of learning and competition. For instance, when installers lobbied in states where they had yet to establish an economic presence, they likely initiated a learning process among state lawmakers. Future research building on this paper might seek to refine methods for distinguishing the types of policy feedback spillovers explored here from traditional diffusion mechanisms. The standard policy diffusion designs are limited in their ability to parse mechanisms , and the feedback dynamics studied here will not always lead to diffusion in a strict sense. Broadly speaking, studying intergovernmental policy feedback in a federal context requires close attention not just to patterns of policy adoption in different units, but also to the political engagement of organized interests across the federal system. Scholars might pay particularly attention to two particular types of groups: first, groups with federated structures that can swiftly leverage resources from one jurisdiction to influence policy in another; and second, business interests seeking to expand. Studying the intergovernmental effects of policies on interest group politics also likely requires examinations over longer periods of time than conventional policy diffusion approaches. Diffusion mechanisms like learning and competition might manifest quickly—since they depend only on the beliefs of lawmakers—while the intergovernmental feed backs studied here depends on long-run shifts to interest group systems.

Indeed, the case of rooftop solar examined here is likely an outlier in the speed by which state policies gave rise to new interests. By adopting this empirical approach, scholars can further extend the theoretical framework developed in this paper. A natural extension is vertical policy feedback . The organized interests that benefit from, and are strengthened by, particular state-level reforms might, in addition to advocating for the propagation of those reforms across the states, advocate for the national-level adoption of those or aligned reforms. These effects have likely been limited in the case of distributed solar, where key decisions are made at the state level. Indeed, while SolarCity, Sunrun, Vivint, SunPower, and SunEdison spent just under 9 million dollars lobbying in the 15 states that collected expenditure data between 2015 and 2017, they collectively spent just 2.25 million dollars lobbying the federal government over the same period . But there is some anecdotal evidence that the growth of the distributed solar lobby, driven in part by state-level decisions,cannabis drying racks commercial has been important to the national politics of issues like tariffs on solar panels and the Solar Investment Tax Credit . Future research might also consider the conditions under which strategic actors intentionally leverage state policy as a political tool in building a political coalition for broader reform—or seeking to dismantle opposing organized interests . Importantly, politicians often face a collective action problem in their efforts to use policy for political gain. Even when a broader party or interest group benefits from a particular policy, individual lawmakers can have incentive to defect . This collective action problem is particularly pronounced for politicians seeking to use state policy for national-level political gain . As a result, we might expect federated groups with political operations across sites and levels of government to be most equipped to strategically harness dynamics of intergovernmental policy feedback . While this paper demonstrates the force of intergovernmental feed backs on interest group politics, these mechanisms are likely more limited in other cases. The aggressive growth strategy of installers, combined with the crucial role of state policy in driving growth, provided a strong incentive for installers to mobilize politically across the states. At the same time, even as rooftop solar firms have mobilized, incumbent electric utilities have been able to prevent pro-solar reforms across a number of states, and in some cases, roll them back . Forward looking incumbents engaged across sites and levels of government in the federal system can, in this way, use the political system to prevent competitors from gaining strength. Moreover, in policy areas like immigration or marriage equality, where sub-national policy decisions are less likely to engender major shifts in the broader interest group landscape, we are unlikely to observe strong policy feedback spillovers operating through organized interests. But at the same time, there are a broad swath of policy issues for which the mechanisms I explore here are likely quite relevant. Indeed, the emergence of supportive interests with a stake in new policy regimes is a fundamental feature of sustainable policy reforms .

These mechanisms are particularly relevant to the politics of the energy transition, where liberal leaning states have led the way, but where there are significantly more greenhouse gas emissions to be abated in conservative-leaning areas. While rooftop solar is just a small piece of the energy transition, similar ideas apply to other elements like utility-scale renewables and energy efficiency . In general, policy feed backs in energy governance tend to be quite powerful, since policies that replace fossil fuel infrastructure with clean energy infrastructure also replace fossil fuel interests with clean energy interests . More broadly, states play important regulatory roles across a number of policy areas, and their decisions can affect the political resources of organized interests active in other states. For instance, in the education system, state policy has been instrumental to the steady growth of charter schools in recent years, which in many states and districts now pose a meaningful challenge to the traditional public-school model—as well as to the teachers unions that draw strength from that model. As charter schools have grown, so has the charter school lobby, as wealthy foundations have allied with charter networks to push forward policies across the states, and also in local and federal politics . The general scope conditions for these types of effects are quite broad. Sub-national policies must give rise to new organized interests or significantly influence the capacities of existing interests. And the organized interests affected by sub-national policies must leverage newfound strength to mobilize horizontally across the federal system. Though this paper focuses specifically on the effects of state policies on business interests, elements of the proposed perspective also likely apply to other types of organized interests , as well as to sub-national jurisdictions apart from the US states .There are reasons to think, in addition, that these types of dynamics are at play even in some areas where we do not observe shifts to policy or interest group landscapes: they can be baked into the status quo. The period of rooftop solar policy and politics I study saw massive policy and interest group changes over a relatively short period of time, which renders the dynamics of policy feedback across the states highly visible. Similar mechanisms, though, can enforce policy stability across the federal system. Many powerful organized interests draw strength from policies in place in jurisdictions across the federal system and use their resources to block threatening policies at multiple sites and levels of government . These dynamics are difficult to study since they tend to lead to non-action. But studying policy areas in flux like rooftop solar can provide insight into forces of stability. Drawing on policy feedback literature and literature on congressional representation, I argue that, because of this institutional configuration, sub-national policy adoption can affect national representation.