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Mary E. Mendoza on the U.S.–Mexico Border Fence Construction

Mary E. Mendoza is a doctoral candidate at the University of California, Davis and a Visiting Instructor at Middlebury College. Her work focuses on the intersections between environmental and borderlands history and has been funded by the National Science Foundation, the Smithsonian, the Ford Foundation, the National Endowment for the Humanities.

Mexican-American border at NogalesCould you briefly describe your dissertation?

My dissertation explores the intersections between the natural and built environments along the U.S.–Mexico border from a transnational perspective. Specifically, it explains the causes, development, and legacy of fence construction along the international boundary line. It argues that the construction of the border fence began in 1911 as a U.S. Department of Agriculture initiative to stop the movement of a cattle tick—a non-human natural threat— and, by 1945, grew into a multi-pronged effort to control the dynamic flow of human migration. And while state-sanctioned efforts to control movement largely failed, the symbolic power of the border increased, creating and solidifying a highly contested and racialized landscape of power, difference, and exclusion by the end of the twentieth century.

What drew your attention to this topic? Whose work encouraged you to pursue this topic and enter this avenue of scholarly inquiry?

I have always been interested in issues related to the U.S.–Mexico border. Growing up in Texas-Mexico borderlands, I read and heard a lot about the ways that migration across the border affected people on both sides of it. Wanting to know more about border crossing, I wondered about the moment the U.S. tried to stop people from crossing by building border fences and opted to write a senior thesis about the history of border fences. From there, my thesis adviser, Kathryn Morse, encouraged me to think about environmental history, and after reading her work and the work of people like Bill Cronon and Richard White, I realized I wanted to pursue my interests from an environmental perspective. That is how I came to write about border fences and the natural environment.

What steps did you take after deciding on this topic to begin to explore your topic?

After the initial thesis work, I took some time off before graduate school and thought about what an environmental history of the U.S.–Mexico border would look like. Two years later, I applied to graduate school and got an M.A. at American University before going to UC Davis. At American, I learned a lot about what it means to study history, and while I was in Washington D.C., I started doing archival research at the National Archives to see what I could find. I began by looking up documents that other border historians like Rachel St. John and Kelly Lytle Hernandez had cited, and those led me to other, more interesting documents.

What particular sources proved the most useful in your work? What limitations or drawbacks did you experience in working with your sources and methods? 

Letters from cattle ranchers to their Congressman have been extremely beneficial as I have thought about the ways in which the natural environment has shaped and been shaped by the construction of the border. In response to a national effort to eradicate a cattle disease known as Texas fever, cattle ranchers who lived near the border protested quarantine measures required of “American” cattle that had wandered into Mexico. Letters like these shed light on the ways in which race, which we generally think of as something that defines phenotypic characteristics of humans, can also be applied to non-human nature. By describing “American” cattle as pure and healthy and calling “Mexican” cattle “tick-infested” and “dirty” in these letters, ranchers created a discourse in which environmental, natural threats defined what was pure, or superior, and what was not. Letters like these also provided insight into what ranchers later thought about Mexican migrants crossing the border for work.

One thing that was particularly challenging about researching this topic was that the border has been overseen by various agencies both in the U.S. and in Mexico, so the documents are spread throughout each country’s individual Departments of Labor, State, Migration, Agriculture, and others.

What future directions do you see for this work? What other questions need to be asked about this topic?

Because this project is broad in scope and focuses only on migration from Mexico, I think it raises questions about how fences have shaped individual border towns or regions, how they have shaped migrants from other countries, how nation-states work to control movement across borders, and how “imagined communities” actively seek to produce spaces of inclusion and exclusion at international borders and within the borders of any given society.

What advice would you offer to others beginning or working on dissertations?

I would say that reading widely is a great way to think about broader connections, so I would encourage graduate students to start there, and then work off of the footnotes of others. Sometimes we see the same sources differently from our different perspectives.

In addition, reading across subfields not only exposes us to different approaches to history, but also reveals some of the gaps in our work. In my work, for example, borderlands history is environmental history—that is, the dividing line itself and the ways that it affects the populations on either side of it, cannot be fully understand without thinking about its surrounding environment.

What would someone outside of your field take from your dissertation?

I think my work could be valuable across disciplines and (hopefully) to the broader public because it addresses key political issues of today. Beyond that, my work brings together a number of key themes that academics study, such as histories of migration, public health and disease, race, racism, and racial formation, environmental degradation, and issues surrounding sustainability and environmental stewardship.

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