In this book, Roger Karapin provides a detailed examination of the factors that shape the adoption of effective climate policy in the United States. The author’s basic argument is that despite structural impediments in American federalism (fragmented power, pluralism combined with the power of economic interests vested in the status quo, a virtually non-existent Green party, and the hollowing out of government capacity), under certain circumstances, there are opportunities for such climate policy-making in the United States. Karapin makes this argument first by analyzing existing climate policies. He casts a wide net and considers the impact of both explicit climate policies—where the stated goal is to reduce Greenhouse Gas (GHG) emission—and implicit policies, where any GHG emission reductions occur in the course of achieving other policy goals, such as improved energy efficiency or enhanced building codes. Using a baseline emissions scenario of “business as usual or no policies” (p. 48) the book reports estimated GHG emissions reductions when explicit and implicit climate policies are implemented at the federal level and within one state, California. This analysis emphasizes what types of policies have the potential to effectively tackle climate change.

With this policy analysis as a backdrop, Karapin then describes the theoretical expectations that inform his investigation of climate policy adoption. Blending insights from comparative politics with public policy research, Karapin details the importance of thinking clearly about structural factors that are largely stable and process factors that are more likely to change over time and across political jurisdictions, such as focusing events, political leadership, interest group mobilization, and public opinion. In this vein, he notes the importance of non-determinist path dependence to link structural and process explanations of policy making. This path dependence is necessary, but not sufficient to create policy change. Karapin embeds insights from structural and process explanations of policy-making into established public policy theories to examine successful climate policy making in all fifty states, as well as offering detailed case studies of California and New York. He modifies John Kingdon’s Multiple Streams Framework to articulate a “windows of opportunity” theory (p. 62) (see John W. Kingdon, Agendas, Alternatives and Public Policy, 1995). To this, he adds insights from the Advocacy Coalition Framework (“The Advocacy Coalition Framework” in Paul Sabatier ed., Theories of the Policy Process, 2007). While more integration of the structure and process theories with the public policy research theories would have added value, I appreciated the author’s effort to provide the broad context of theories stemming from comparative politics as well as public policy making theories.

In Chapter 5, Karapin presents the results of a fifty-state cross-sectional analysis examining the correlates of climate policy adoption. This type of analysis is important, but the book’s real strength lies in the case studies that follow the quantitative analysis. Here, Karapin delves into climate policy-making in two states, California and New York. These states have been leaders in environmental policy making, including climate policy. The case studies provide an important historical perspective often missing in many contemporary examinations of climate policy making. Of course, selecting on the dependent variable creates methodological challenges. Most importantly, when the dependent variable only highlights successful policy making, understanding the influence of independent variables is impossible. While I would have liked to see a case study of an unsuccessful state included in the research, Karapin’s approach to the qualitative research is creative; he takes advantage of temporal variation within California and New York and identifies twenty-two periods of policy making. Within these periods, there are policy making successes and failures. Using a theoretically informed, mixed methods approach to his research question, Karapin thus provides stronger evidence for understanding why some effective climate policies emerge in some jurisdictions at certain points in time, but not in other jurisdictions at other points in time.

The case studies explore how structural and process variables influenced implicit and explicit climate policies in California and New York. In California, he traces climate policy back to the 1940s when the state became active in air pollution mitigation, and in New York he traces climate policy back to the early 1970s. Using a range of sources, the author documents the ability of process variables—such as interest group mobilization, growing problem conditions, and political leadership—to operate and overcome the structural barriers in American federalism, particularly when these process variables create path dependency. For example, the case studies highlight the importance of administrative capacity. A well-resourced and professionally competent bureaucracy can facilitate climate policy making. In California in the late 1960s, the California Air Resources Control Board (CARB) was established. The existence of CARB in the 1960s, with its technical expertise and wide-reaching jurisdiction, is an important factor enabling California to be a current leader in explicit climate change policy. In addition to highlighting the importance of administrative capacity, Karapin’s analysis suggests that problem conditions, environmental interest group mobilization, and committed leadership are also important elements needed to promote effective climate policy.

While there is considerable scholarship exploring climate policy adoption in the United States, Political Opportunities for Climate Policy adds strength and clarity to this growing field. The clear treatment of implicit and explicit climate policy is an important contribution, as is the mixed methods scholarship. Political Opportunities for Climate Policy will be of interest to scholars and practitioners interested in subnational environmental policy-making in general and climate change in particular. Scholars with an interest in either California or New York climate policy should read this book; the case studies are exceptionally well documented and rich in detail. Ultimately, Karapin’s research suggests that there are opportunities for climate policy in the United States. Given the change at the federal level, with the Trump Administration openly hostile to advancing climate change policy, understanding the conditions under which states may be able to advance successful climate policy over the longer term takes on even greater importance.