During the 1920s, American 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 wish raised fear 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 "jazz age". Many traditional-minded Americans felt that the immigrants were dangerously political 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.
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