The Policy of Border Fencing Between the United States and Mexico: Permeability and Shifting Functions‪.‬

In the late 1990s those who knew of Cabeza Prieta National Wildlife Refuge (CPNWR) considered it a treasure: an area of pristine desert in southwestern Arizona. Over the following ten years the refuge has sustained some of the most extensive environmental degradation along the U.S.-Mexico border due to increasing numbers of illegal crossers. This damage occurred in part because past actions to curtail illegal crossings did not eliminate the stream of people illegally entering the United States. Instead these policies shifted the location of the crossings from the increasingly impermeable urban regions to the more porous rural segments of the border. This paper assesses the U.S. federal policies and management practices that affect the permeability of the U.S.-Mexico border. (1) By examining the policies and practices over time and in a variety of regions, the paper identifies the shifting, increasingly impermeable function of the U.S.-Mexico border. The paper begins with a discussion of environmental concerns along the border, using CPNWR as an example. It then explores the functions of the border created by policy and created through implementation, and examines the impact of these functions on the border, including the border environment. The paper concludes with a discussion of possible pathways for future policies and management that move toward a view of the larger picture: providing protection without isolation.