A SHORT HISTORY OF U.S. IMMIGRATION

1848: The Treaty of Guadalupe Hidalgo ends the Mexican-American War and extends citizenship to the approximately 80,000 Mexicans living in Texas, California and the Southwest.

1862: The Homestead Act provides up to 160 acres of Western land free to settlers who agree to develop and live on it, thereby spurring an influx of immigrants from overpopulated countries in Europe seeking land of their own.

1919: The first Red Scare leads to an outbreak of fear and violence against people deemed to be political radicals and foreigners considered to be susceptible to communist propaganda and more likely to be involved in the Bolshevik Revolution.

1924: After a generation of increasingly strict immigration, a new law limits immigration from Eastern and Southern Europe, and halts legal immigration from East and Southeast Asia.

1952: A new law enacted over President Harry S. Truman's veto removes restrictions based on race, but maintains a quota system designed to make sure the country always looks the same, in terms of ethnic makeup, as it did in 1920.

1965: Congressional reform removes discrimination based on national origin, a system considered racially biased because it favored Northern Europeans, and gives higher priority to family unification, job skills and refugee status, preferences that increased the number of immigrants from Southeast Asia.

1986: A new law gives amnesty to undocumented immigrants who had been U.S. residents since 1982 and to certain agricultural workers, imposes sanctions for employers who knowingly hire undocumented workers and steps up border security.

Sources: U.S. Department of Homeland Security, University of California, Berkeley, Harvard University and University of Montana