“Today, the annual tidal wave of over a million immigrants . . . is endangering our American way of life.” —Americans for Immigration Control

“Immigration is not undermining the American experiment; it is an integral part of it.” —Daniel T. Griswold

Between 1790 and 1920 the population of the United States grew from 4 million to 106 million. About 1 million new immigrants—most of them European—had arrived each year, and by the 1920 census, the foreign-born comprised more than 13 percent of the U.S. population. Responding to public anxieties about this large influx of newcomers, Congress passed the Quota Act in 1921, which set a cap of 360,000 new immigrants per year. This act also established a national- origins preference that favored immigrants from England, Scandinavia, Germany, and France over those from southern Europe, Asia, and Africa. Coupled with the impact of the Depression and World War II, these...