All periods in U.S. history when immigration has been reduced or halted:

The restriction/reduction periods were:

1790s — racialized naturalization limits and alien deportation power.

1875–1882 — first federal exclusion laws.

1882–1943 — Chinese exclusion.

1885–1907 — contract labor, pauper, disease, anarchist, and morality exclusions.

1907–1924 — Japanese and broader Asian restrictions.

1917–1965 — literacy test, Asiatic Barred Zone, national-origins quotas.

1929–1945 — Depression-era administrative restriction and Mexican repatriation.

1940s–1952 — wartime and Cold War ideological/security restrictions.

1952–1965 — McCarran-Walter quota/security regime.

1965–1978 — new worldwide and hemispheric caps despite ending national-origin discrimination.

1980s — refugee ceilings, employer sanctions, unauthorized-labor enforcement.

1990s — expanded detention, deportation, benefit restrictions, asylum limits.

2001–2008 — post-9/11 security restrictions.

2017–2020 — travel bans, refugee reductions, asylum restrictions, public-charge expansion.

2020–2023 — COVID/Title 42 and visa-entry restrictions.

2024 — Biden southern-border asylum/entry restrictions.

2025–2026 — refugee-admissions suspension and expanded travel/visa restrictions.