List of All Presidents' Use of Military Without Congressional Approval

A historical review of how presidents from both parties have repeatedly used military force without obtaining a formal declaration of war or new Authorization for Use of Military Force (AUMF)

Published on Mar. 2, 2026

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In the aftermath of President Donald Trump's military intervention against Iran, Democratic leaders and several media figures quickly argued that the strikes were unconstitutional because Congress did not first authorize military force. However, this article provides a verified historical record showing that presidents from both parties have repeatedly used military force without obtaining a formal declaration of war or new AUMF since World War II. The article includes context and political objections where they occurred, highlighting the long-standing constitutional tug-of-war between the executive and legislative branches over the use of military power.

Why it matters

This history is relevant because it shows that unilateral or semi-unilateral presidential military action has become the norm, not the exception, across Democratic and Republican administrations. The modern Iran controversy fits into this long-standing constitutional debate rather than representing a novel break from precedent. Understanding this broader context is important for evaluating the validity of claims about the legality and propriety of a president's use of military force without explicit congressional approval.

The details

The article provides a detailed chronological account of how presidents from Truman to Biden have used military force without congressional declarations of war, including actions in Korea, Lebanon, Cuba, Vietnam, Cambodia, Laos, Grenada, Libya, Panama, Bosnia, Sudan, Afghanistan, Iraq, Syria, Yemen, and more. In each case, the president relied on legal justifications such as Article II commander-in-chief powers, UN authority, prior AUMFs, and claims of emergency self-defense. Congress often objected after the fact, occasionally supported the action retroactively, and frequently did both at once.

  • Since World War II, presidents from both parties have repeatedly used military force without obtaining a formal declaration of war or new Authorization for Use of Military Force (AUMF).
  • Unilateral or semi-unilateral presidential military action has become the norm, not the exception.

The players

Harry S. Truman

Committed U.S. forces to Korea after North Korea invaded South Korea, acting under a United Nations Security Council resolution rather than seeking a congressional declaration of war.

Dwight D. Eisenhower

Deployed ~14,000 U.S. troops to stabilize Lebanon amid regional unrest, justified under the Eisenhower Doctrine to counter Soviet influence in the Middle East.

John F. Kennedy

Approved the covert CIA-backed paramilitary Bay of Pigs invasion of Cuba without congressional authorization, and also ordered the Cuban blockade, legally framed as a 'quarantine' to avoid calling it an act of war.

Lyndon B. Johnson

Oversaw a massive troop escalation in the Vietnam War following the Gulf of Tonkin Resolution, which Congress authorized force broadly but did not declare war.

Richard Nixon

Conducted secret bombing campaigns in Cambodia and Laos, expanding the Vietnam War without new congressional authorization, which directly led to the War Powers Resolution of 1973.

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What they’re saying

“We must not let individuals continue to damage private property in San Francisco.”

— Robert Jenkins, San Francisco resident (San Francisco Chronicle)

“Fifty years is such an accomplishment in San Francisco, especially with the way the city has changed over the years.”

— Gordon Edgar, grocery employee (Instagram)

What’s next

The judge in the case will decide on Tuesday whether or not to allow Walker Reed Quinn out on bail.

The takeaway

This case highlights growing concerns in the community about repeat offenders released on bail, raising questions about bail reform, public safety on SF streets, and if any special laws to govern autonomous vehicles in residential and commercial areas.