18th & 19th Centuries (Founding 1900)
Undeclared Hostilities & Limited Force
- 17981800 Quasi-War with France (naval engagements) undeclared naval conflict. Congressional Research
- 18011805 First Barbary War (North Africa) naval/landing operations against pirates without a formal declaration of war. Congressional Research
- 1815 Second Barbary War U.S. squadron attacks Algerian forces; no U.S. declaration of war. Congressional Research
- Numerous 19th-century "Small Wars" Marines/naval forces landed in Latin America, the Caribbean, Central America, and Asia to protect U.S. interests, often without prior Congressional declaration (e.g., interventions in Nicaragua, Uruguay, China). Congressional Research
Quote:
Note: These early deployments often lacked formal congressional declarations, though some later received funding.
20th Century (19011999)
Major Undeclared Wars & Campaigns
- 19501953 Korean War engaged under U.N. auspices without a U.S. declaration of war. Congress.gov
- 19641973 Vietnam War (Escalation) U.S. combat expanded after the Gulf of Tonkin Resolution (a broad authorization, not a war declaration). Congress.gov
- Lebanon Peacekeeping & Beirut 1982-83 Marines sent without specific prior approval. X (formerly Twitter)
- 1983 Invasion of Grenada (Operation Urgent Fury) no specific prior congressional authorization. X (formerly Twitter)
- 1986 Bombing of Libya (Operation El Dorado Canyon) U.S. air strikes without prior congressional approval. Wikipedia
- 1989 Invasion of Panama (Operation Just Cause) removed Noriega without a war declaration. X (formerly Twitter)
- 1998 Operation Infinite Reach cruise-missile strikes on al-Qaeda in Afghanistan and a factory in Sudan (no new congressional authorization). Wikipedia
Quote:
_After 9/11, Congress passed the 2001 Authorization for Use of Military Force (AUMF) a broad, continuing authorization often interpreted as permitting many actions without new specific approvals. However, for many uses listed below, no new congressional authorization was sought or passed.*
Drone Strikes, Targeted Killings, Special Operations
- 2001present Global drone strikes & special operations against al-Qaeda, Taliban, ISIS affiliates in Pakistan, Yemen, Somalia, Libya, Philippines, etc. These were conducted under the 2001 AUMF or presidential authority without specific congressional re-authorization for each strike. X (formerly Twitter)+1
- 2002 Marib airstrike (Yemen) CIA drone killed AQ leader and others; no separate congressional approval. Wikipedia
- 2011 Killing of American Anwar al-Awlaki (Yemen) U.S. drone strike targeting an American citizen without trial or prior congressional authorization. Congress.gov
- 2011 Raid killing Osama bin Laden (Pakistan) SEAL special operation conducted without prior congressional vote (only later notification). X (formerly Twitter)
- 2011 Libya Intervention (Operation Odyssey Dawn) U.S. air operations enforcing a no-fly zone under NATO/UN without a specific U.S. congressional authorization. Wikipedia
- 20142017 Airstrikes vs. ISIS in Iraq/Syria initiated under broad AUMFs but without a distinct new congressional authorization. X (formerly Twitter)
- 2017 Raid on Yakla (Yemen) U.S. special forces killed militants and civilians; authorized by the executive without fresh congressional approval. Wikipedia
(Examples from 20212025.)
- 2021 Airstrikes in Syria (Biden) against Iran-backed militia without specific congressional authorization. X (formerly Twitter)
- 2024 U.S. strikes on Houthi targets (Biden) in Yemen without a new congressional authorization. X (formerly Twitter)
- 2025 Airstrike on Venezuelan cartel vessel (Trump) in the Caribbean under executive authority with no congressional approval; legal experts question the basis. Reuters
- 2025 Aerial strikes on Iranian nuclear facilities (Trump) ordered without prior congressional authorization (debated as outside existing war powers). X (formerly Twitter)