The effect of nativism in the United States in the 1920s was primarily reflected in the quota system. Nativism during this period led to a heightened focus on restricting immigration and favoring native-born Americans over immigrants, which culminated in the Immigration Act of 1924. This act established national origin quotas that severely limited immigration from countries outside Western Europe, aiming to preserve the ethnic composition of the U.S. population.
The Scopes Trial (1925) was more about the conflict between science and religion, particularly regarding the teaching of evolution, while the Jones Act of 1917 related to the status of Puerto Ricans and is not directly connected to 1920s nativism.