History and geography have given Mexico a unique status in the U.S. immigration system, and have made the Mexico-U.S. migration flow the largest in the world. Mexicans are the largest group of U.S. migrants across most types of immigration statuses—a fact that may have important implications for how Congress makes U.S. immigration policy. This report reviews the history of immigration policy and migration flows between the countries and the demographics of Mexicans within the United States. It also analyzes contemporary issues in U.S. immigration policy and the impact Mexico may have on U.S. immigration outcomes.
The U.S.-Mexican migration system has passed through four main phases since the early 20th century. Migration flows were limited and mainly short-term prior to the 1920s, and Mexicans were exempted from certain immigration restrictions and admitted as the first U.S. guest workers during World War I. The bilateral "Bracero" temporary worker program marked a second phase, with 4.6 million temporary visas issued to Mexican workers between 1942 and 1964. With the end of the Bracero program and other immigration reforms in 1965, along with social and economic changes in the United States and Mexico, the third stage was marked by growing illegal inflows, eventually leading Congress to pass the Immigration Reform and Control Act of 1986. Finally, despite a series of additional enforcement measures, the Mexican population in the United States doubled during each decade since 1970, with unauthorized migrants accounting for a majority of the growth, followed by legal family-based immigration.
Today, the Mexico-born population in the United States stands at about 11.7 million people. Compared to other migrants, the Mexican born in the United States are more likely to be unauthorized, be younger, have lower education levels, work in lower-skilled occupations, and have lower measures of economic well-being. In contrast with earlier periods and virtually all other migrants, Mexicans are now dispersed throughout all 50 U.S. states.