Undeclared war
{{Short description|Type of military conflict}}
{{about|the type of military conflict|the 1990 film|Undeclared War|the 2022 television series|The Undeclared War}}
{{war}}
{{Use dmy dates|date=July 2022}}
An undeclared war is a military conflict between two or more nations without either side issuing a formal declaration of war. The term is sometimes used to include any disagreement or conflict fought about without an official declaration. Since the United Nations' police action in the Korean War,{{cite web|last=Truman|first=Harry S.|date=29 June 1950|title=The President's News Conference of June 29, 1950|publisher=Teachingamericanhistory.org|url=http://teachingamericanhistory.org/library/index.asp?document=594|access-date=4 January 2011}} some governments have pursued disciplinary actions and limited warfare by characterizing them as something else such as a military action or armed response.
Under customary international law, it is not necessary to declare war—simply beginning hostilities is sufficient to make belligerent intentions clear.{{cite web |title=Declaration of war |url=https://casebook.icrc.org/a_to_z/glossary/declaration-war |website=International Committee of the Red Cross |access-date=2024-02-09}}
United States
{{Further|Declaration of war by the United States}}
There is no specific format required under United States law for the way an official war declaration will be structured or delivered. The United States Constitution states: "The Congress shall have Power […] To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water".[https://usconstitution.net/xconst_A1Sec8.html "U.S. Constitution - Article 1 Section 8"].
As of September 2024, the United States Congress has formally declared war 11 times, and has not done so since 1942; 6 of these were WWII declarations.{{Cite web|url=https://www.theatlantic.com/politics/archive/2013/08/all-the-previous-declarations-of-war/279246/|title=All the Previous Declarations of War|last=Franke-Ruta|first=Garance|date=31 August 2019|website=The Atlantic|language=en-US|access-date=2019-09-01}} The United States did not declare war during its involvement in Vietnam, although the Gulf of Tonkin Resolution authorized the escalation and use of military force in the Vietnam War without a formal declaration of war.{{cite news|title=The Law: The President's War Powers|newspaper=Time|date=1 June 1970|url=http://www.time.com/time/magazine/article/0,9171,878290,00.html|archive-url=https://web.archive.org/web/20080107101712/http://www.time.com/time/magazine/article/0,9171,878290,00.html|url-status=dead|archive-date=January 7, 2008|access-date=28 September 2009}} On at least 125 occasions a US president has employed military forces without authorization from Congress.{{Cite journal|last=Yoo|first=John C.|last2=Delahunty|first2=Robert J.|date=2002|title=The President's Constitutional Authority to Conduct Military Operations Against Terrorist Organizations and the Nations that Harbor or Support Them|journal=SSRN Working Paper Series|pages=502|doi=10.2139/ssrn.331202|issn=1556-5068|url=https://scholarship.law.berkeley.edu/cgi/viewcontent.cgi?article=1570&context=facpubs|access-date=14 January 2020|archive-date=26 April 2019|archive-url=https://web.archive.org/web/20190426071815/https://scholarship.law.berkeley.edu/cgi/viewcontent.cgi?article=1570&context=facpubs|url-status=dead}} One of the most significant of these occasions was the Korean War, where the United States led a peacekeeping United Nations force to stop North Korea's invasion against South Korea. The conflict resulted in over 142,000 American casualties (about 40,000 deaths and over 100,000 injuries).
Russia
No formal declaration of war has been issued in the ongoing Russo-Ukrainian War. When the Russian president, Vladimir Putin, launched the full-scale invasion of Ukraine in 2022, he used the euphemistic phrase 'special military operation.'[https://theconversation.com/putins-ukraine-invasion-do-declarations-of-war-still-exist-177880 Putin's Ukraine invasion - do declarations of war still exist?], R. Pullen, C. Frost, The Conversation, March 3, 2022]
Other examples
The Falklands War between Argentina and the United Kingdom (April–June 1982) was never formally declared as a war.{{Cite web |title=A Short History of the Falklands Conflict |url=https://www.iwm.org.uk/history/a-short-history-of-the-falklands-conflict |access-date=2024-02-25 |website=Imperial War Museums |language=en}}