IMMIGRATION History
 

Immigration has played an important role in American history, and the United States continues to have the most open immigration policy in the world. Before the era of rapid communications and transportation, America encouraged relatively open immigration to settle its empty lands. After certain states passed immigration laws following the Civil War, the Supreme Court in 1875 declared the regulation of immigration a federal responsibility. The Immigration Service was established in 1891 to deal with the big increase in immigration which started in 1880.

The outbreak of World War I reduced immigration from Europe, but mass immigration resumed upon the war's conclusion, and Congress responded with a new immigration policy: the national-origins quota system, passed in 1921 and revised in 1924. Immigration was limited by assigning each nationality a quota based on its representation in past U.S. census figures. Also in 1924, Congress created the U.S. Border Patrol within the Immigration Service.

There was very little immigration over the next 20 years, with net immigration actually dropping below zero for several years during the Depression. Immigration remained relatively low during the 20 years following World War II, because the 1920s national-origins system remained in place after Congress re-codified and combined all previous immigration and naturalization law into the Immigration and Nationality Act of 1952. American agriculture continued to import seasonal labor from Mexico, as they had during the war, under a 1951 formal agreement between the United States and Mexico that made the Bracero Program permanent.

In 1965, Congress replaced the national origins system with a preference system designed to unite immigrant families and attract skilled immigrants to the United States. This change to national policy responded to changes in the sources of immigration since 1924. The majority of applicants for immigration visas now came from Asia and Latin America rather than Europe. The preference system continued to limit the number of immigration visas available each year, however, and Congress still responded to refugees with special legislation. Not until the Refugee Act of 1980 did the United States have a general policy governing the admission of refugees.

Legal immigration alone in the 1990s likely matched or exceeded the previous historical peak decade of 1901-1910, when 8.8 million legal immigrants were admitted. Adding the settlement of illegal aliens makes the 1990s without doubt the period of greatest immigration in America's history.