Making permanent the principle of national origin quotas, the Johnson-Reed Act served as the basis for U.S. immigration policy until the McCarran-Walter Immigration and Naturalization Act (1952). The measure established an overall annual quota of 153,700, allotted according to a formula based on 2 percent of the population of each nation of origin according to the census of 1890. Countries most favored according to this formula were Great Britain (43 percent), Germany (17 percent), and Ireland (12 percent). Countries whose immigration had increased dramatically after 1890—including Italy, Poland, Russia, and Greece—had their quotas drastically slashed. Following passage of the Emergency Quota Act in 1921, isolationist opinions hardened in the country. As the politics of eastern Europe remained turbulent, the Soviet experiment became more publicized, and the racialist message of eugenics became more widely accepted, American politicians determined that a permanent measure to dramatically reduce immigration was needed. The Johnson-Reed Act ensured that the vast majority of future immigrants would, in the words of Tennessee congressman William Vaile, “become assimilated to our language, customs, and institutions,” and “blend thoroughly into our body politic.” Immigrants born in independent countries of the Western Hemisphere were not subject to the quota. Other nonquota immigrants included wives of citizens and their unmarried children under 18 years of age; previously admitted immigrants returning to the country; ministers and professors, their wives, and their unmarried children under 18; students; and Chinese treaty merchants. The Johnson-Reed Act prohibited entry of aliens not eligible for citizenship, thereby formally excluding entry of Japanese, Chinese, and other Asian immigrants. The 2 percent formula was designed to be temporary and was replaced with an equally restrictive formula in 1927 that provided the same national origin ratio in relation to 150,000 as existed in the entire U.S. population according to the census of 1920.