John Hultgren’s Border Walls Gone Green: Nature and Anti-Immigrant Politics in America examines the understudied convergence of anti-immigration activism and environmentalism, with special attention devoted to Mexico-U.S. migration. Using discourse analysis, Hultgren identifies different versions of “environmental restrictionism” that have existed since the late 19^th century, as well as the contemporary “global environmental justice” perspective that opposes restrictionism. The definition of nature emerges as central in the book. The author finds that each discourse treats its respective definition as given, and from that foundation develops its respective, exclusionary conception of sovereignty. Hultgren’s own “environmental political theory of migration,” in contrast, moves past this approach, treating migrants as important activists within his envisioned U.S. environmental movement.

Early environmental restrictionists portrayed immigrants as a threat to the environment and to the white race. When World War II rendered such blatant eugenicist positions unacceptable, the new focus became “carrying capacity,” or the idea that a particular space can support only a limited number of people. Restrictionists now claimed that an influx of immigrants from the developing world would bring environmental, social, and political—especially communist—challenges to American sovereignty.

Environmental restrictionism lives on in discourses employed by anti-immigration groups and by their alliances with environmentalists. “Ecological nativism” retains carrying capacity at its core, presenting overcrowding as a threat to the national wilderness and thus sovereignty. “Social nativists” rely on either interpretations of Christianity or social Darwinism to try to justify preventing non-white migrants from entering the country.

Hultgren devotes more attention to “ecocommunitarian restrictionism” than to nativism. Like ecological nativists, ecocommunitarians argue that immigration harms the environment by driving population growth. Yet they also identify neoliberalism as a culprit—the force behind “a flexible, mobile labor force with no sense of place” (p. 107). Ecocommunitarians conceive of “nature” as territorially located within nation-state boundaries, and they turn to the state to prevent immigration in the name of protecting nature.

For Hultgren, ecocommunitarianism has the potential to gain support among progressive environmentalists both because it is subtler than the other restrictionist discourses and because he believes that current criticisms of ecocommunitarianism rest on shaky ground. The global environmental justice community sees ecocommunitarians as racists who only pretend to care about the environment, whereas Hultgren thinks these restrictionists probably “care so much about a particular nationalized conception of nature that they view efforts to protect it as ethical regardless of the implications on marginalized immigrant populations” (pp. 133–134). Contrary to ecocommunitarians, global environmental justice enthusiasts argue that we should worry not about population size, but instead about over-consumption driven by capitalism, and that if we focus on these dynamics, we will see that the lifestyle of immigrants is ecologically low-impact and thus ecofriendly—that “immigrants live closer to nature” (p. 133). Hultgren notes however that this pattern of behavior lasts only “so long as this populace adheres to the consumptive practices of the lower socioeconomic echelon” (p. 134). Ultimately, as Border Walls Gone Green reveals, the global environmental justice discourse does not question the foundations of ecocommunitarianism. Starting from its definition of “nature,” each view arrives at a particular conception of sovereignty that distinguishes between insiders and outsiders: “The ethos of sovereignty is being reconfigured in a more inclusive direction, but the constituent parts of sovereignty—the nation, the state, citizenship, liberal democracy, capitalism, and a vision of progress founded on a particularistic ‘we’—remain intact” (p. 138).

Hultgren seeks to develop a “unified, revolutionary model of resistance” (p. 161) to counter these versions of sovereignty. His environmental political theory of migration incorporates migrants as political actors in the U.S. environmental movement for which he advocates. He describes migrants as highly attuned to ecological and cultural connections among places. He uses this idea of “place-in-relation” (p. 167) to lead us to his proposal that “local and national [environmental] activists employ a migratory lens in formulating their strategies” (p. 169).

Also on a normative level, Hultgren is deeply disturbed by the focus on global threats but national-level solutions that is present in both the global environmental justice and ecocommunitarian discourses (e.g., p. 94, 138). Specifically with regard to ecocommunitarianism, he writes: “While the extreme political economic impacts of neoliberalism are recognized… ecocommunitarianism continues to rely on black-boxed notions of ‘national cultures’ and state-centric logics of morality” (p. 94), and he is critical that the discourse does not instead adopt a “transnational ethic” (p. 110). The author has a related, empirically-based critique of the idea of turning to the state to solve global challenges: “Neoliberalism does not require a strong state to counterbalance it; neoliberalism has actually strengthened particular institutions within the state (e.g., Border Patrol, Department of Defense)” (p. 150). We might situate the book alongside other analyses that have similarly observed the conjunction of, on one hand, market dynamics—including at the international level—and on the other hand, national and/or local regulatory regimes (e.g., see Steven K. Vogel, Freer Markets, More Rules, 1996; José Carlos G. Aguiar, “Smugglers, Fayuqueros, Piratas,” Political and Legal Anthropology Review, 2013).

Border Walls Gone Green makes several important contributions to the literatures on sovereignty and environmentalism. It is based on careful research on several manifestations of environmental restrictionism, which has influenced immigration policies in the United States and which could shape future social organizing and public policy. Hultgren’s discourse analysis offers convincing evidence that “sovereignty” has been socially constructed by powerful groups in society and not imposed from above by the state. Furthermore, the book’s migrant-based theory is highly original, also for its implications for thinking about sovereignty. The theory provides a foundation for challenging the exclusionary dimension of citizenship-based sovereignty that is so prevalent—empirically and in the literature—as discussed for example by Deborah J. Yashar (Contesting Citizenship in Latin America, 2005, 35–42).

Worth noting is that the book’s treatment of sovereignty as contestable and changeable potentially draws our attention away from the ways by which ideas and norms surrounding a particular version of sovereignty may become institutionalized and take on their own power. More generally, the book could have explored in more depth the possible role of institutions as forces independent of activist goals or large-scale economic structures. For instance, how might migrants become institutionalized through living and working in the United States? Could a process of institutionalization alter their perceptions of the ecological and/or cultural interconnectedness among places, thus making them more or less obvious candidates to be the activists portrayed within the book’s migrant-based theory?

By opening these avenues of inquiry regarding the role of institutions, and especially through its empirical and theoretical insights, this book is a valuable contribution to our understanding of the politics surrounding immigration, environmentalism, sovereignty, and their intersection.