Answer:
the passage of the Immigration and Nationality Act.
Step-by-step explanation:
The Immigration and Nationality Act was passed in 1965 in order to abolish the National Origins Formula. The National Origins Formula had been the basis of immigration policy since the 1920s, and it had attempted to reduce immigration from Asia, Southern Europe and Eastern Europe. However, during the 1960s, this law was criticized for being racially discriminatory. Therefore, the Immigration and Nationality Act was passed in order to eliminate these quotas.