How did new laws change U.S. immigration policy in the 1920s?
Quotas were introduced in 1921 and 1924.
In 1921, the Immigration Restriction Act imposed quotas based on ethnicity, the number of immigrants could not exceed 3% of the total population for any ethnicity. For instance Jewish immigrants could not exceed in number 3% of the total number of Jews in the USA. It was also known as the Emergency Quota Act or Emergency Immigration Act.
It was made stricter in 1924 by the Johnson-Reed Act which lowered the quotas to 2%.
In the Twenties, Racist and eugenist ideas were very fashionable. These laws were aimed at promoting a WASP immigration (White Anglo-Saxon Protestant) from Northern Europe and thwart Jewish immigration and immigration from Southern and Eastern Europe. The KKK had millions of members and organized rallies in Washington D.C.
It was not repealed before the 1960s and the Immigration and Nationality Act of 1965 which favored skills over ethnicity and family relationships for immigration preference.