The literature on the history of US conservation policy includes many books on the history of public lands, water, and wildlife policies; a few on public health policies; and a very few that attempt an overview of all of these phenomena and how they have come together to form the foundations of modern US environmental policies (e.g., Richard Andrews, Managing the Environment, Managing Ourselves: A History of American Environmental Policy, 3^rd ed., 2020). Almost without exception, however, these books focus on the policies expressed in statutes and regulations and on the actions of the administrative agencies, with only limited mention of the legal and constitutional arguments that were battled out in the courts.

In The Conservation Constitution, Kimberly Smith provides a valuable new complement to these studies by presenting a far more detailed history of the legal and constitutional arguments presented to and ultimately decided by the courts during the period from 1870 to 1930—a period in which US policies for using and managing the natural environment and its resources were profoundly reshaped, and federal and state governments’ authority to manage and regulate them was ultimately confirmed. Smith’s chapters take us through a succession of constitutional debates and judicial decisions over the authority of state and federal authority for conservation management: first of wildlife, then of forests, then of western and subsequently eastern federal forest reserves and federal lands more generally, of state and eventually federal pollution control, and ultimately of the uses of interstate compacts for multiple-use water resource projects and other purposes.

Smith’s primary aim, well summarized in the final chapter (pp. 254ff.), is “to explain how lawyers and judges reworked constitutional doctrine to accommodate the expansion of state power over the natural environment during the Progressive era; and more specifically, how legal decisionmakers conceptualized the natural environment, its relation to human society, and the public interests at stake to create the constitutional ‘common sense’ that federal and state governments have authority to protect natural resources and the integrity of ecosystems in the interest of future generations.” In the process, she discusses the interweaving of principles such as the public trust doctrine, the police power, public nuisance doctrine, parens patriae standing, the interstate compacts clause, and federal constitutional arguments based on the interstate and foreign commerce, property, war, treaty, spending, and eminent domain powers, as well as the interstate nuisance doctrine. She argues that even though many of these issues continue to be argued in the modern era, the sheer number of these constitutional foundations, once accepted by the courts, has ultimately made governmental environmental management authority strongly resilient to challenges. She also urges greater recognition of the roles of skilled lawyers and judges, along with the better-known politicians and citizen advocates, in achieving this stronger role for the state in environmental conservation. Finally, she notes the continuing need for further evolution of our understanding of the Constitution: the Progressive understanding did not address the distributive imperfections of environmental regulation, nor the implications of administrative processes for procedural justice, nor—perhaps most problematic today—the absence of effective capacity for national economic and environmental planning, particularly in international cooperation to address global environmental challenges such as climate change.

Overall, this book makes a valuable addition to the literature on conservation policy history by providing a richly detailed parallel history of the key legal cases, arguments, and court decisions by which state and federal conservation policy was ultimately—although with some continuing challenges—confirmed as legal and constitutional. To Smith’s credit, her writing makes arguments that are sometimes dense and arcane to nonlawyers interesting and worth the effort to follow.

Any broad history such as this one unavoidably leaves out some details that one might wish for. This seemed most evident to me in the chapters on pollution-control policies. For example, Smith does not discuss the judicial decisions in the late nineteenth century that essentially overruled the common-law rights of riparian property owners to water “undiminished in quantity and quality” and substituted a philosophy that industrial pollution had become widely accepted as a necessary cost of “progress”—there by necessitating later statutory solutions to this problem in the form of federal pollution-control regulations. And in discussing the history of federal power to protect public health from water pollution (pp. 215–19) and the transformation of the Marine Hospital Service into the US Public Health Service in 1912, she notes its scientific mission but misses its important early exercise of its authority to regulate drinking water quality on interstate carriers such as trains and ships—an important extension of the Commerce Clause—which in turn compelled the many local stops along their routes to provide safe drinking water to them. This was one of the most significant early antecedents of the regulatory authority of the modern Environmental Protection Agency.

One could make a similar point about Smith’s discussion of federal irrigation policy, which she dates to the 1894 Carey Act: it overlooks the important history of the federal irrigation surveys in the late 1880s and associated reservations of federal lands from claims (to prevent speculation), which placed the head of the US Geological Service in the controversial role of arbiter of the entire federal lands system; it also led to the 1981 forest reserves rider, a key turning point in the relationship between rights to claim federal lands as private property and the authority of the federal government to withhold them from such claims.

A smaller quibble is Smith’s claim that both public health professionals and sanitary engineers were united in their acceptance of the “miasma” (“filth”) theory of disease causation as late as 1900 (p. 184). This theory was scientifically disproven in the 1880s by Koch, Pasteur, and others, and by the 1890s sanitary engineers had begun to introduce drinking water treatments such as mechanical and sand filtration—yet continued to argue that the treatment of water supplies was more cost effective than the treatment of wastewater, because “running water purifies itself” and “the solution to pollution is dilution” (leaving downstream communities more vulnerable to water contamination). Public health professionals, meanwhile, had shifted their attention from miasmas and environmental cleanup to laboratory-based “new public health” priorities based on bacteriological science.

One broader issue that I would question is Smith’s reference to these policies as instances of “green government.” She makes a thought-provoking point about the successful use of arguments favoring protection of forest ecosystems for their benefits to streamflow and water supply, and of birds for their control of agricultural insect pests, describing these as early arguments for protecting what today would be called “ecosystem services.” This seems to me a valuable reminder that not all these arguments are new. To refer generally to this era as an advance of “green government,” however, seems to me a bit too casual. Progressive policies were sometimes “green” in the sense of protecting natural species and ecosystems, and certainly they were improvements over previous unregulated exploitation—yet most were instances of government-led economic development, with major (and often not green) transformative impacts on the environment.

With these mild criticisms, however, this is an otherwise valuable book.