During the 1920s, Americans generally became more nativist. This is not to say that there had been no nativism in the US prior to that decade. However, in the 1920s nativism became more prevalent.
Since the 1880s, there had been a flood of “new immigrants” to the United States. These immigrants were “new” because they came from different regions than previous immigrants had. These new immigrants came from Southern and Eastern Europe rather than from Northern and Western Europe. Many of the new immigrants were Jewish. Many others were Catholic and Catholics were still viewed with suspicion by many Americans. Finally, many of the new immigrants held to radical political beliefs such as socialism and anarchism.
After World War I, a backlash against these immigrants arose. This was due partly to the recent Bolshevik Revolution in Russia which raised fears of a similar revolution in the United States. It was also due in part to the changes that were occurring as American culture (particularly in cities) moved into the “Jazz Age.” Many traditional-minded Americans felt that the immigrants were dangerous politically and identified the immigrant-laden cities with the bad new cultural developments.
It was for these reasons that anti-immigrant sentiment strengthened. This is seen most clearly in the immigration restriction acts of the 1920s. These laws were meant to reduce the flow of “new immigrants” and to encourage immigration by Northern and Western Europeans instead.
During the 1920s, the political and social climate of the United States became nativist, meaning that many people were unfriendly towards the idea of immigration. In part, this was a reaction to the fear of Communism in the aftermath of the Russian Revolution of 1917. In 1919, several bombs were mailed to prominent people around the country, including Attorney General A. Mitchell Palmer and J.P. Morgan, Jr. Though no one died in these bombings (or another series of bombings later that year), they sparked a series of raids and crackdowns on radical and anarchist groups organized by A. Mitchell Palmer that became known as the Palmer Raids.
There was also a great fear of anarchism, in part a reaction to the trial and conviction of Sacco and Vanzetti, Italian-born anarchists, for the murder of a guard and paymaster during an armed robbery in Massachusetts in 1920. Though historians still debate today whether Sacco and Vanzetti were guilty or not, their trial helped further ignite fear of Southern and Eastern European immigrants, including Italians, Jews, Slavs, and others, as anarchists. The Immigration Act of 1924 created a quota on immigrants that used the 1890 census to set limits on new immigration. The act was aimed at reducing immigrants from Southern and Eastern Europe and from Africa. In addition, the act completely banned Arabs and immigrants from Asia. The nativist current did not really change until after World War II, when millions of refugees from war-torn Europe and elsewhere found a new home in the United States.