Migration and Immigration Since 1990

The Immigration and Nationality Act of 1965 scrapped the national-origins quota system that had favored Northern and Western Europe since the 1920s. It replaced country quotas with preferences for family reunification and needed job skills, and set no cap on immigration from the Western Hemisphere. The law's authors did not expect it to transform who came to America, but it did: by opening the door equally, it let migration flow toward wherever push and pull factors were strongest, which after 1965 meant Mexico, the Philippines, Vietnam, China, India, and Central America. That is why the foreign-born share of the population, under 5 percent in 1970, climbed past 13 percent by the 2010s, with Latin America and Asia supplying most of the growth instead of Europe.

Border enforcement policy has shaped the shape of migration more than its size. Stricter patrolling of traditional crossing points, especially after the 1990s, pushed migrants toward more remote and dangerous routes and encouraged many to settle permanently in the United States rather than cycle back and forth seasonally, since recrossing became riskier. Total unauthorized population growth responded less to enforcement intensity than to labor demand and conditions in sending countries.

At the same time, Americans moved within the country, continuing a Sun Belt migration that began after World War Two. Air conditioning, defense spending, lower taxes, cheaper housing, and service and tech-sector jobs drew people from the Northeast and Midwest into metro areas like Phoenix, Atlanta, Dallas, and Charlotte. Both migrations, one international, one domestic, remade the electoral map and metropolitan growth patterns that define the country today.