Before 1965, immigration from the Western Hemisphere was not numerically capped; Latin Americans faced qualitative exclusions (health, criminality, “public charge”) but not quota ceilings like Europeans and Asians did. The shift in 1965 imposed the first hemisphere and later per‑country limits on Latin America, which fundamentally re‑channeled migration, economics, and politics across the U.S.–Latin America relationship.[1][2][3]

Legal framework up to 1965

• National‑origins quotas (1921–1965):
  • The 1921 and 1924 laws set strict numerical quotas aimed mainly at restricting Southern and Eastern Europeans and excluding Asians; these quotas applied only to the Eastern Hemisphere.[3][4]
  • The Western Hemisphere—Canada, Mexico, Caribbean, Central and South America—remained outside the numerical quota system, so there was no fixed annual cap, even though other grounds of inadmissibility still applied.[2][1][3]
• Western Hemisphere status:
  • Until the 1965 Immigration and Nationality Act, immigrants from Latin America needed to meet documentary and sponsorship requirements but not compete for quota numbers.[2]
  • In 1968, the 1965 Act took full effect, creating a 170,000 cap for the Eastern Hemisphere and, for the first time, a 120,000 annual cap for the Western Hemisphere, plus a 20,000 per‑country limit.[3][2]

In practice, this meant that before 1965 the “border” for Latin Americans was controlled more by inspection and labor demand than by hitting an annual numerical ceiling.[5][1]

Borders and labor: the Bracero era

• Bracero Program (1942–1964):
  • The U.S. and Mexico created a large guest‑worker system to supply agricultural and railroad labor during and after World War II.[6][5]
  • More than 4–5 million contracts were issued over 22 years, making it the largest formal foreign worker program in U.S. history.[5][6]
• Border enforcement logic:
  • During the height of Bracero, authorities often “channeled” unauthorized Mexican laborers into legal Bracero contracts rather than treating them as permanent illegal entrants.[6][5]
  • A Congressional study later found the program “instrumental” in reducing illegal immigration by absorbing seasonal workers into a legal, if exploitative, circuit.[5]
• End of Bracero:
  • Under growing criticism from U.S. labor and civil‑rights advocates, and over Mexico’s objections, Congress allowed the Bracero Program to end in 1964.[1][6]
  • Many men who had circulated as temporary workers now had ties in the U.S.; when legal contracts vanished, they increasingly returned as unauthorized migrants and began bringing families, shifting the flow from circular to more permanent settlement.[1][5]

So pre‑1965 border management with Mexico was a hybrid of open legal quotas (no numerical cap) plus a large, state‑managed labor pipeline; once that pipeline and the uncapped status disappeared, irregular flows rose.[1][5]

How 1965 changed U.S.–Latin America migration

• First caps on Latin America:
  • The 1965 Act abolished national‑origins quotas but simultaneously imposed hemisphere caps and per‑country limits, directly constraining Latin American legal entries for the first time.[7][8][2]
  • These Western Hemisphere limits were pushed through in part by segregationist and restrictionist members of Congress who feared rising non‑European immigration.[8][7][1]
• Policy feedback and unauthorized migration:
  • Research links the combination of the Bracero termination (1964) and the new Western Hemisphere caps (effective 1968) to a sharp increase in unauthorized migration, especially from Mexico.[3][5][1]
  • Migrants with long histories of legal temporary work now faced hard legal ceilings and fewer visas; rather than stop moving, they adapted by staying longer in the U.S. and organizing family migration outside formal channels.[5][1]

In other words, numerical caps were introduced after dense, circular migration networks already existed, so the main effect was to “illegalize” established patterns rather than to prevent them.[1][5]

Effects on migration patterns, economics, politics

Migration patterns

• Before 1965:
  • Flows from Latin America were largely uncapped, heavily male, and often seasonal or circular, especially through Bracero and other labor streams.[6][5]
  • Movement was shaped by U.S. labor demand and bilateral agreements, with relatively less emphasis on absolute numerical limits.[6][5]
• After caps:
  • The introduction of Western Hemisphere and country caps, combined with the end of Bracero, helped transform a predominantly temporary labor flow into long‑term settlement, family migration, and rising unauthorized residence.[3][5][1]
  • Over time, Latin Americans—especially Mexicans and Central Americans—made up a growing share of the undocumented population, even as legal pathways narrowed.[3][1]

Economic consequences

• For the U.S.:
  • Pre‑1965 policies allowed employers, especially in agriculture and railroads, to rely on cheap, flexible Mexican and other Latin American labor without worrying about hitting quota ceilings.[5][6]
  • After restrictions and the end of Bracero, employers still demanded low‑wage labor; instead of regulated guest workers, they increasingly turned to unauthorized workers, which weakened labor protections and contributed to an informalized workforce.[1][5]