Which U.S. presidents issued the largest single‑event or mass clemency proclamations in history, and why?

1. Carter’s blanket pardon: national reconciliation after Vietnam

President Jimmy Carter’s 1977 proclamation forgiving Vietnam‑era draft evaders stands as the paradigmatic mass clemency by scope and intent — a categorical amnesty designed to close a deeply divisive national chapter by restoring rights to a very large class of people rather than adjudicating individual merits, and it remains one of the largest single‑act uses of the pardon power in U.S. history ^{[1] [4]}.

2. Biden’s December 2024 single‑day surge: targeted categorical commutations and pardons

President Joe Biden’s December 12, 2024 action commuted the sentences of roughly 1,499 people and pardoned 39 others, with the White House calling it the largest single‑day grant of clemency in modern history; his administration also used categorical proclamations earlier (marijuana possession; certain former service members convicted under anti‑gay statutes), illustrating a strategy of systemic remedying of perceived injustices rather than case‑by‑case mercy ^{[2] [3] [5]}.

3. Truman, FDR and other mass restorations: wartime deserters and broad practice

Other presidents have likewise used clemency en masse: Harry Truman issued clemency to thousands of World War II deserters in 1947 to restore civil rights and stabilize postwar society, and Franklin D. Roosevelt was one of the most prolific users of pardons over his long tenure, with several thousand actions recorded — demonstrating that large‑scale clemency is not new and often reflects postwar or broad policy choices ^{[1] [6]}.

4. Ford, proclamations excluded from DOJ tallies, and counting problems

Official DOJ clemency statistics typically exclude persons granted pardons by proclamation as part of a class (for example, Carter’s draft‑evader pardons and actions from Ford’s Presidential Clemency Board), which complicates simple numerical comparisons of “who issued the most” and understates the scale of some presidents’ categorical actions if one looks only at Office of the Pardon Attorney tables ^{[4] [7]}.

5. Motives: reconciliation, justice reform, politics and end‑of‑term timing

Presidents cite a mixture of motives when granting mass clemency — national reconciliation after war (Carter, Truman), correcting systemic legal injustices (Biden’s marijuana and LGBTQ‑service‑member proclamations), and political loyalty or favor (critics argue some high‑profile pardons reflect cronyism) — and many presidents concentrate acts of clemency late in their terms, making “single‑day” tallies a frequent phenomenon ^{[1] [3] [2] [8]}.

6. Who, then, issued the largest mass actions — the historical verdict

By categorical, single‑proclamation scope, Jimmy Carter’s 1977 pardon of Vietnam draft evaders —often counted in the hundreds of thousands— is the signature mass pardon in U.S. history, while by single‑day volume in the modern record, Joe Biden’s Dec. 12, 2024 commutations and pardons rank as the largest single‑day action; broader cumulative tallies vary by source (some count Biden as the most prolific president overall), and counting conventions (proclamation classes vs. individual Office of the Pardon Attorney entries) explain much of the disagreement in raw totals ^{[1] [3] [5] [4]}.

7. Caveats, competing counts and what the data conceal

Different sources produce different headline numbers — DOJ charts exclude class proclamations, media outlets and White House statements emphasize “largest ever” claims for political effect, and secondary tallies (e.g., FDR’s thousands or disputed totals for recent presidents) must be read with attention to methodology; reporting therefore supports a clear two‑part answer (categorical proclamations like Carter’s vs. concentrated single‑day packages like Biden’s), but precise rankings depend on which counting rules one accepts ^{[4] [2] [6] [5]}.