1 This article builds on a 2013 report released by the Binational Migration Institute at the University of Arizona which provided data on migrant deaths investigated by the Pima County Office of the Medical Examiner from 1990-2012 (see Martinez et al. 2013). It provides updated data on migrant deaths through the fiscal year 2013 as well as updated demographic characteristics for migrants who have been positively identified since the publication of the 2013 report. This research could not have been possible without the dedicated and meticulous work of forensic professionals at the Pima County Office of the Medical Examiner, now and in the past. The Colibrí Center for Human Rights has provided invaluable data-management and insight. The Tucson-based immigrant rights organization, Coalición de Derechos Humanos, has tracked migrant deaths in Arizona since 2003, providing the groundwork for this research. Studies completed by the Binational Migration Institute in the Department of Mexican American Studies at the University of Arizona in 2006 and 2013 were generously supported by the Pima County Board of Supervisors. The Pima County Board of Supervisors has also been very supportive of the Pima County Office of the Medical Examiner in its efforts to investigate suspected unauthorized border crosser deaths. We thank M. Melissa McCormick for her work on the 2006 report. Thanks to Inez M. Duarte and Kat Rodriguez for their assistance in the data collection and data entry process, to Jessica Hamar Martínez and Ricardo D. Martínez-Schuldt for looking over early drafts of the article. We also thank the Little Chapel of All Nations for their continued support. We gratefully acknowledge the contributions of all those who have worked on the issue of migrant deaths for years.

Border walls permeate our world, with more than thirty nation-states constructing them. Anthropologists Margaret E. Dorsey and Miguel Díaz-Barriga argue that border wall construction manifests transformations in citizenship practices that are aimed not only at keeping migrants out but also at enmeshing citizens into a wider politics of exclusion. For a decade, the authors studied the U.S.-Mexico border wall constructed by the Department of Homeland Security and observed the political protests and legal challenges that residents mounted in opposition to the wall. In Fencing in Democracy Dorsey and Díaz-Barriga take us to those border communities most affected by the wall and often ignored in national discussions about border security to highlight how the state diminishes citizens' rights. That dynamic speaks to the citizenship experiences of border residents that is indicative of how walls imprison the populations they are built to protect. Dorsey and Díaz-Barriga brilliantly expand conversations about citizenship, the operation of U.S. power, and the implications of border walls for the future of democracy.

This article makes the case for addressing nonhumans as actors in geopolitical processes such as boundary making and enforcement. The challenge of this line of argumentation is to account for nonhumans as actors without enacting dualistic ontologies that locate the natural and social in separate realms. To address this methodological challenge, I present a posthumanist political ecology. I elaborate my argument and methodological approach in relation to my research on the environmental dimensions of U.S. border security. Specifically, I examine how deserts, rivers, Tamaulipan Thornscrub, and cats inflect, disrupt, and obstruct the daily practices of boundary enforcement, leading state actors to call for more funding, infrastructure, boots on the ground, and surveillance technology. As my research illustrates, taking nonhumans seriously as actors alters explanations for the escalation of U.S. enforcement strategies.

Scott Warren is a political geographer and a volunteer with the Arizona humanitarian organization No More Deaths. On January 17, 2018, Warren was arrested in Ajo, Arizona, along with Kristian Perez-Villanueva and José Sacaria-Goday, two Central American migrants to whom he was providing care. The United States has since charged Warren with two counts of felony harboring under 18 USC § 1324(a) and one count of conspiracy related to harboring. This paper seeks to place the Scott Warren case in context. First, it situates the charges against Warren within a longer genealogy of Prevention Through Deterrence (PTD), the overarching enforcement strategy pursued by the United States along its border with Mexico since 1994. Next, it discusses how the charges against Warren reflect a doubling-down on PTD and its underlying logic. This involves an aggressive neoliberal agenda being pursued by the Trump administration on multiple fronts, one designed to forcibly dismantle long-existing networks of community, care, and solidarity across difference in the transnational U.S.-Mexico border region.

Governmentality, Immigration, illegality. This book frames the study of immigration within the Michel Foucault inspired theories of governmentality. Specifically, it focuses on the government of migrant illegality. It is concerned, on the one hand, with the kinds of knowledge, the specific problematizations, and the various authorities that have constructed “illegal” immigrants as targets of government; and, on the other, with the specific tactics, techniques, and programs that have been deployed to manage this population. The book, in short, is concerned with how “illegal” immigrants have been problematized as objects of knowledge and governmental intervention.