Throughout American history, there continued to be a conflict between those who supported continued immigration and those who opposed it. In 1894, the Immigration Restriction League was founded. It supported literacy-tests for would- be immigrants. The literacy test passed in Congress in 1896, but was vetoed by President Grover Cleveland, who insisted that the United States should remain a haven for all oppressed people.
President Theodore Roosevelt, however, was a strong supporter of the literacy test. In addition, responding to the assassination of President McKinley, he called for the exclusion of anarchists. Congress promptly legislated the exclusion of anarchists, and four years later of those who were "imbeciles, feeble minded and people, with physical or mental defects."
In 1907, the Congress appointed a joint House-Senate Committee called the Dillingham Commission. Its report called for the issuance of literacy tests. It also suggested restrictive policies that would limit immigration based on national origin. The Congress passed a bill requiring a literacy test, but President Wilson vetoed it. In 1917, the Congress once again passed a bill requiring literacy for immigrants. Wilson once again vetoed the bill, but this time the Congress overrode the veto.
The rising nationalism that occurred during World War I, as well as the support given by the labor unions, resulted in the passage of the Immigration Bill of 1921, which limited immigration to 3% of the population of the United States, based on the 1910 census.