By the end of the twentieth century, the policies put into place by the Immigration and Nationality Act of 1965 had greatly changed the face of the U.S. population. In the 1950s more than half of all immigrants were Europeans and just 6 percent were Asians; by the 1990s only 16 percent were Europeans and 31 percent were of Asian descent, while the percentages of Latino and African immigrants had also increased significantly. Between 1965 and 2000, the highest number of immigrants (4.3 million) to the United States came from Mexico, in addition to some 1.4 million from the Philippines. Korea, the Dominican Republic, India, Cuba, and Vietnam were also leading sources of immigrants. Illegal immigration became a potent political issue during this time. Many low-wage workers worried that immigrants would threaten their job prospects and others feared a drain on federal and state resources.

The Immigration Reform Act in 1986 attempted to provide better enforcement of immigration policies and create more avenues for legal immigration. The act included two amnesty programs for unauthorized immigrants and collectively granted amnesty to more than 3 million others. Another piece of immigration legislation, the 1990 Immigration Act, modified and expanded the 1965 act, increasing the total level of immigration to 700,000. The law also provided for the admission of immigrants from “underrepresented” countries to increase the diversity of the immigrant flow.

With some modifications, the policies enacted by the Immigration and Naturalization Act of 1965 are the same ones governing U.S. immigration in the early twenty-first century. Noncitizens currently enter the United States lawfully in one of two ways, either by receiving either temporary (non-immigrant) admission or permanent (immigrant) admission.