Following the Quota Act of 1921 that established a system of national origin statistics, the legislature followed up with the immigration law of 1924, also referred to as the Johnson-Reed Act. This was the first permanent immigration law that instituted and created much of the national origin system, as well as shaped immigration policy, until the legislature opened up the process in the 1960's; it also defined many important terms for United States immigration, among them were the inherent different between an immigrant and non-immigrant.
The first important nuance in the Immigration Act of 1924 was the establishment of a future immigration policy. It called for a two-tiered system that would limit immigration drastically in the short-term. Whereas the original quota system specified that they would utilize during the 1910 census, the 1924 immigration law stretched further back to 1890 continuing to utilize national origin; it also changed the previous three percent allowance to two percent, which effectively limited immigration to just over one-hundred and fifty thousand individuals.
This first portion was to be in effect until 1927 when the second part of the legislation would kick-in and change the quotas from based on the 1890 census to the amount of foreign-born citizens in the country in 1920. The second portion would not only be based on a national origin system, but would also be pushed back and eventually come into effect in 1929.
Also important, was the newly-established legal definition of an immigrant versus a non-immigrant. It stated that anyone not entering the country as an immigrant would be effectually a non-immigrant. The non-immigrant classification would be further broken-down into classes of acceptable entry. It also called for the consular control system that stated that no non-immigrant would be granted access to the nation without a proper visa.
Many scholars point to underlying philosophies of the time that likely caused such a piece of legislation. The belief of Eugenics appears in several scholarly viewpoints on the Immigration Act of 1924. Assuming that Caucasians, essentially of North and West European descent, were preferred immigrants; the national origin quotas attempted to maintain the racial make-up of the country. Eugenics placed a maxim on this ethnic-based policy and established clear-cut racist tendencies on the institution of American immigration.
This racially-tinged policy would remain at the forefront of legislation until the middle of the 1960's. This national origin system could have feasibly worked if it was based more on neutral numbers such as the amount of applicants, but as treated, it presented a complex history of racism and inherent prejudice.