Many of the first immigrants to the new country were from northern/western Europe. Anti-Irish and anti-Catholic sentiments were high. By the late 1800s, people from the rest of Europe and China had begun coming in. Resentment of the Irish, Italians, and Chinese grew. 2/10
It was in this context that America's *first* federal immigration law was signed into law: the Chinese Exclusion Act of 1882, which explicitly barred almost all immigration from China. This ban was extended more broadly to other parts of Asia in 1917. 3/10
A big change came to the immigration system in 1924, when the country, for the first time, introduced *numerical quotas* based on country of origin. They were an explicit attempt at racial engineering and gave strong preference to immigrants from northern/western Europe. 4/10
The 1924 law is considered to be the predecessor to the current system of country caps. The national quotas it instituted were designed to keep out southern and eastern Europeans, especially Italians and Jews, while banning virtually all Asian immigration. 5/10
By 1965, there was increasing pressure to make the immigration system more equitable, and the National Origins Formula was replaced. The system was replaced with immigration caps that were uniform across countries. 6/10
Interestingly, the reason country caps weren't removed entirely was precisely to keep some level of racial engineering. To pass the 1965 reform, lawmakers in Congress had to convince xenophobic skeptics that "hordes of Africans and Asians" would not be flooding the US. 7/10
Just take a look at the remarks made during a Congressional hearing by Congressman Emanuel Celler (D-NY), who sought to bring an end to the highly restrictive immigration law of 1924. 8/10 
Ultimately, the xenophobes made the wrong bet, as high immigration from Europe didn't really materialize. Rather, the US has seen a large influx of immigrants from Asian countries such as China, India, and the Philippines in recent years. 9/10
The full House congressional record containing these remarks can be found here: govinfo.gov/content/pkg/GP… (see pp. 21757-21758)
