In this paper, we examine the correlation between sectoral shocks and border enforcement in the United States. Enforcement of national borders is the main policy instrument the U.S. government uses to combat illegal immigration. We see whether border enforcement falls following positive shocks to sectors that are intensive in the use of undocumented labor, as would be consistent with political economy models of illegal immigration. The main finding is that border enforcement is negatively correlated with lagged relative price changes in the apparel, fruits and vegetables, and livestock industries and with housing starts in the western United States. This suggests that authorities relax border enforcement when demand for undocumented labor is high.

In this paper, we examine the impact of enforcement of the U.S.-Mexico border on wages in U.S. and Mexican border regions. The U.S. Border Patrol polices U.S. boundaries, seeking to apprehend any undocumented entrants. It concentrates its efforts on the Mexican border. We examine labor markets in border areas of California, Texas, and Mexico. For each region, we have high-frequency data on wages and person hours the U.S. Border Patrol spends policing the border. 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) illegal immigration from Mexico has a minimal impact on wages in U.S. border areas.