Illegal Immigration, State Law, and Deterrence

A critical immigration policy question is whether state and federal policy can deter undocumented workers from entering the U.S. We examine whether Arizona SB 1070, arguably the most restrictive and controversial state immigration law ever passed, deterred entry into Arizona. We do so by exploiting a unique data set from a survey of undocumented workers passing through Mexican border towns on their way to the U.S. Results indicate the bill’s passage reduced the flow of undocumented immigrants into Arizona by 30 to 70 percent, suggesting that undocumented workers from Mexico are responsive to changes in state immigration policy. In contrast, we find no evidence that the law induced undocumented immigrants already in Arizona to return to Mexico.