Final answer:
The U.S. enacted the Quota System in the 1920s to maintain American homogeneity, reduce immigration from certain regions, and protect jobs, while politically exempting Western Hemisphere countries due to economic interests.
Step-by-step explanation:
The United States established a Quota System as part of their immigration policy in the 1920s to preserve American homogeneity and address rising nativist sentiment following World War I and the Russian Revolution. The Emergency Quota Act of 1921 and the National Origins Act of 1924 set numeric limits based on a percentage system linked to past US census figures, effectively reducing immigration from Southern and Eastern Europe, Asia, and other regions while favoring immigrants from Northern and Western Europe.
Additionally, the acts responded to economic and labor concerns, aiming to protect American jobs and wages during the post-war recession. However, no restrictive quotas were applied to countries from the Western Hemisphere due to political compromises linked to industry and agriculture demands, highlighting the complexity of immigration policies and their link to domestic economic interests.