The historic reason attitudes towards immigration changes is because of scale. This [1] page has a nice graph of the foreign born US population. Towards the end of the 19th century it hit 14.8% which led to significant pushback that culminated in various laws and acts against immigration. That's precisely where the paperwork started to form.

Following those acts and laws, immigration declined to a valley of 4.7% foreign born in 1970. Then it began rising again with more permissive/enabling acts playing a significant role in driving such, like IRCA under Reagan. In any case we're now up to 15.8% with no end in sight, and history is, as always, not just repeating, but practically plagiarizing itself.

[1] - https://www.pewresearch.org/short-reads/2025/08/21/key-findi...