The Sacco and Vanzetti case provides the most dramatic evidence of this nativism. In 1920 a botched robbery at a shoe company in South Braintree, Massachusetts, resulted in the murder of the bookkeeper and guard. Police arrested Nicola Sacco, a shoemaker, and Bartolomeo Vanzetti, a fish peddler, and charged them with the crime. These two Italian immigrants shared radical political views as anarchists and World War I draft evaders. The subsequent trial revolved around their foreign birth and ideology more than the facts pertaining to their guilt or innocence. The presiding judge at the trial referred to the accused as “anarchistic bastards” and “damned dagos” (a derogatory term for “Italians”). Convicted and sentenced to death, Sacco and Vanzetti lost their appeals for a new trial. Criticism of the verdict came from all over the world. Workers in Mexico, Argentina, Uruguay, France, and Morocco organized vigils and held rallies in solidarity with the condemned men. The American minister to Venezuela reported that “practically all the lower classes regarded them as martyrs.” Despite support from influential lawyers such as Harvard’s Felix Frankfurter, the two men were executed in the electric chair in 1927.

The Sacco and Vanzetti case provides an extreme example of 1920s nativism, but the anti-immigrant views that contributed to the two men’s conviction and execution were commonplace during the period and shared by Americans across the social spectrum. Many Americans, including Henry Ford, saw immigrants as a threat to cherished traditions. In his commitment to “One-Hundred Percent Americanism,” Ford tried to preserve traditional values. He strongly supported prohibition and denounced the frenetic sounds and sexual overtones of Jazz Age music and dancing. Ford felt that immigrants were the cause of a decline in American morality. He contended that aliens did not understand “the principles which have made our [native] civilization,” and he blamed the influx of foreigners for society’s “marked deterioration” during the 1920s. He stirred up anti-immigrant prejudices mainly by targeting Jews. Believing that an international Jewish conspiracy was attempting to subvert non-Jewish societies, Ford serialized in his company newspaper the so-called Protocols of the Elders of Zion, an anti-Semitic tract concocted in czarist Russia to justify pogroms against Jews. Ford continued to publish it even after the document was proven a fake in 1921.

Ford joined other nativists in supporting legislation to restrict immigration. In 1924 Congress passed the National Origins Act, a quota system on future immigration. The measure limited entry by any foreign group to 2 percent of the number of people of that nationality who resided in the United States in 1890. The statute’s authors were interested primarily in curbing immigration from eastern and southern Europe. They chose 1890 as the benchmark for immigration because most newcomers from those two regions entered the United States after that year. Quotas established for northern Europe, about 70 percent of the total, went unfilled, while those for southern and eastern Europe could not accommodate the vast number of people who sought admission. The law continued to bar East Asian immigration altogether.

With immigration of those considered “undesirable” severely if not completely curtailed, some nativist reformers shifted their attention to Americanization, which developed into one of the largest social and political movements in American history. Speaking about immigrants, educator E. P. Cubberly said, “Our task is to break up their groups and settlements, to assimilate and amalgamate these people as a part of our American race, to implant in their children the northern-European conception of righteousness, law and order, and popular government.” Business corporations conducted Americanization and naturalization classes on factory floors. Schools, patriotic societies, fraternal organizations, women’s groups, and labor unions launched citizenship classes. Even the U.S. Catholic hierarchy joined the effort by prohibiting the creation of new parishes based on nationality and increasingly requiring the use of English for confessions and sermons.

In the Southwest and on the West Coast, whites aimed their Americanization efforts at the growing population of Mexican Americans. Subject to segregated education, Mexican Americans were expected to speak English in their classes. “The opening of school,” an Arizona teacher’s journal noted, “will provide an opportunity for all the Mexican children . . . to study under separate tutelage until they have acquired a thorough mastery of the English language.” Anglo school administrators and teachers generally believed that Mexican Americans were suited for farmwork and manual trades. For Mexican Americans, therefore, Americanization meant vocational training and preparation for low-status, low-wage jobs.

Despite attempts at Americanization, ethnic groups did not dissolve into a melting pot and lose their cultural identities. First-generation Americans—the children of immigrants—learned English, enjoyed American popular culture, and dressed in fashions of the day. Yet in cities around the country where immigrants had settled, ethnic enclaves remained intact and preserved the religious practices and social customs of their residents. Americanization may have watered down the “vegetable soup” of American diversity, but it did not completely eliminate the variety and distinctiveness of its flavors.