Does Border Enforcement Protect U.S. Workers from Illegal Immigration?

In this paper, we examine the impact of government enforcement of the U.S.-Mexican border on wages in the border regions of the United States and Mexico. The U.S. Border Patrol polices U.S. boundaries, seeking to apprehend any individual attempting to enter the United States illegally. These efforts are concentrated on the Mexican border, as most illegal immigrants embark from a Mexican border city and choose a U.S. border state as their final destination. We examine labor markets in southern California, southwestern Texas, and Mexican cities on the U.S.-Mexico border. For each region, we have high-frequency time-series data on wages and on the number of person hours that the U.S. Border Patrol spends policing border areas. For a range of empirical specifications and definitions of regional labor markets, we find little impact of border enforcement on wages in U.S. border cities and a moderate negative impact of border enforcement on wages in Mexican border cities. These findings are consistent with two hypothesis: (1) border enforcement has a minimal impact on illegal immigration, or (2) immigration from Mexico has a minimal impact on wages in U.S. border cities.