Casus belli

"Act of War" redirects here. For other uses, seeCasus belli (disambiguation)andActs of war (disambiguation).

Acasus belli(fromLatincasus belli'occasion for war';pl.casus belli) is an act or an event that either provokes or is used to justify awar.Acasus belliinvolves direct offenses or threats against the nation declaring the war, whereas acasus foederisinvolves offenses or threats against its ally—usually one bound by a mutual defense pact.Either may be considered anact of war.Adeclaration of warusually contains a description of thecasus bellithat has led the party in question to declare war on another party.

Terminology

The termcasus bellicame into widespread use in Europe in the seventeenth and eighteenth centuries through the writings ofHugo Grotius(1653),Cornelius van Bynkershoek(1707), andJean-Jacques Burlamaqui(1732), among others, and due to the rise of the politicaldoctrineofjus ad bellumor "just wartheory ".The term is also used informally to refer to any "just cause" a nation may claim for entering into a conflict. It is used to describe the case for war given before the term came into wide use,and to describe the rationale for military action even without aformal declaration of war(as in:the lead up to the Gulf of Tonkin Resolution).

In formally articulating acasus belli,a government typically lays out its reasons for going to war, its intended means of prosecuting the war, and the steps that others might take to dissuade it from going to war. It attempts to demonstrate that it is going to war only as a last resort or plan (ultima ratio) and that it has "just cause" for doing so. Moderninternational lawrecognizes at least three lawful justifications forwaging war:self-defense, defense of an ally required by the terms of a treaty, and approval by the United Nations.

Proschema(pluralproschemata) is the equivalent Greek term, first popularized byThucydidesin hisHistory of the Peloponnesian War.The proschemata are the stated reasons for waging war, which may or may not be the same as the real reasons, which Thucydides calledprophasis(πρóφασις). Thucydides argued that the three primary real reasons for waging war are reasonable fear, honor, and interest, while the stated reasons involve appeals to nationalism or fearmongering (as opposed to descriptions of reasonable, empirical causes for fear).

Reasons for use

Countries need a public justification for attacking another country, both to galvanize internal support for the war and to gain the support of potential allies.

In thepost–World War II era,theUN Charterprohibits signatory countries from engaging in war except: 1) as a means of defending themselves—or an ally where treaty obligations require it—against aggression; 2) unless the UN as a body has given prior approval to the operation. The UN also reserves the right to ask member nations to intervene against non-signatory countries that embark onwars of aggression.

Categorisation

Braumoeller (2019) stated: "However idiosyncratic thecasus bellimay seem, however, there generally is one... The issues that prompt most wars fit fairly well into one of a fairly manageable number of categories. "He broadly summarised classical issues as territory, the creation or dissolution of countries, the defence of the integrity of countries, dynastic succession, and the defence of co-religionists or co-nationals.He pointed out that in the modern field ofpeace and conflict studies,scholars also frequently list causes such as "struggle for power, arms races and conflict spirals, ethnicity and nationalism, domestic political regime type and leadership change, economic interdependence and trade, territory, climate change-induced scarcity, and so on".

InThe Causes of War(1972), Australian historianGeoffrey Blaineymentioned general causes such as miscalculation, as well as specific causes such as "Death Watch and Scapegoat Wars", and emphasised the importance of mundane factors such as weather.

Theodore K. RabbandRobert I. Rotbergexplored the roots of major conflicts as a mixture of factors on the international, domestic and individual level inThe Origin and Prevention of Major Wars(1989).

Kalevi Holsticatalogued and categorised wars from 1648 to 1989 according to 24 categories of "issues that generated wars".

Acasus belliintentionally based on inaccurate facts is known as apretext.

Historical examples

This section outlines a number of the more famous and/or controversial cases ofcasus belliwhich have occurred in modern times.

Second Opium War

Europeans had access to Chinese ports as outlined in theTreaty of Nankingfrom theFirst Opium War.France used the execution ofAuguste Chapdelaineas acasus bellifor theSecond Opium War.On February 29, 1856, Chapdelaine, a French missionary, was killed in the province ofGuangxi,which was not open to foreigners. In response, British and French forces quickly took control ofGuangzhou(Canton).

American Civil War

Further information:Origins of the American Civil WarandBattle of Fort Sumter § Decisions for war

While long-term conflict between theNorthernandSouthern States(mainly due to moral questions caused byslavery,as well as socio-economic disparities) was the cause of theAmerican Civil War,theConfederateattack on Fort Sumter(April 12–14, 1861) served ascasus bellifor theUnion.HistorianDavid Herbert Donald(1996) concluded that PresidentAbraham Lincoln's "repeated efforts to avoid collision in the months between inauguration and the firing on Ft. Sumter showed he adhered to his vow not to be the first to shed fraternal blood. But he also vowed not to surrender the forts. The only resolution of these contradictory positions was for the confederates to fire the first shot; they did just that."Confederate veteranWilliam Watsonopined in 1887 that up until that point, U.S. Secretary of StateWilliam H. Sewardhad not been able to find 'a just cause to declare war against the seceded States', but Sumter gave him 'thecasus bellihe had sought'.Watson lamented howJefferson Davisand other Confederate leaders were 'vainglorious[ly]' celebrating the victory at Sumter, while forgetting that making the first move had given the Confederacy the immediate internationally negative reputation of being the aggressor, and had granted Seward 'the undivided sympathy of the North'.

Spanish–American War

Cartoon of belligerentUncle Samplacing Spain on notice, c. 1898

TheMainewas a United States Navy ship that sank inHavana Harbor,Spanish Cubaon February 15, 1898. While the destruction of theMainedid not result in an immediate declaration of war with Spain, it did create an atmosphere that precluded a peaceful solution.The Spanish investigation found that the explosion had been caused by spontaneous combustion of the coal bunkers, but the US Sampson Board's Court of Inquiry ruled that the explosion had been caused by an external explosion from a torpedo. TheMcKinleyadministration did not cite the explosion as acasus belli,but others were already inclined to go to war with Spain over perceived atrocities and loss of control in Cuba.Advocates of war used the rallying cry, "Remember theMaine!To hell with Spain! "

World War I

See also:Causes of World War I

Austria-Hungary's casus belli against Serbia in July 1914 was based uponSerbia's refusal to investigate the involvement of Serbian government officials in the equipping, training and paying the assassins who murdered Archduke Franz Ferdinand of Austria atSarajevo.The Serbian government refused the Austrian Démarche, and Austria-Hungary declared war.

For Britain, the direct cause of entering the war was the German invasion and occupation ofBelgium,violating Belgian neutrality which Britain was bound by treaty to uphold.

In 1917, the German Empire sent theZimmermann Telegramto Mexico, in which they tried to persuade Mexico to join the war and fight against the United States, for which they would be rewarded Texas, New Mexico, and Arizona, all former Mexican territories. This telegram was intercepted by the British, then relayed to the U.S., which led to PresidentWoodrow Wilsonthen using it to convince Congress to join World War I alongside the Allies. The Mexican president at the time, Venustiano Carranza, had a military commission assess the feasibility, which concluded that this would not be feasible for a number of reasons.

World War II

InJapanese Manchuria,Japan staged theMarco Polo Bridge Incidentin 1937 as a casus belli to initiate the Second World War.

In his autobiographyMein Kampf,Adolf Hitlerhad in the 1920s advocated a policy ofLebensraum( "living space" ) for theGerman people,which in practical terms meant German territorial expansion into Eastern Europe.

Alfred Naujocks,who organized and led theGleiwitz incidenton the orders ofHeydrich.

In August 1939, to implement the first phase of this policy,Germany'sNazigovernment under Hitler's leadership staged theGleiwitz incident,which was used as acasus bellifor theinvasion of Polandthe following September. Nazi forces usedconcentration campprisoners posing as Poles on 31 August 1939, to attack the German radio station Sender Gleiwitz in Gleiwitz, UpperSilesia,Germany (since 1945:Gliwice,Poland) on the eve of World War II.Poland's allies, theUKandFrance,subsequently declared war on Germany in accordance with their alliance.TheUnited Stateswould declare war onJapanafter the attack onPearl Harboron December 7, 1941.

In 1941, acting once again in accordance with the policy of Lebensraum,Nazi Germanyinvaded the Soviet Union,using thecasus belliofpreemptive warto justify the act of aggression.

Vietnam War

Many historians have suggested that the SecondGulf of Tonkin Incidentwas a manufactured pretext for theVietnam War.North Vietnamese Naval officials have publicly stated that during the second incident theUSSMaddoxwas never fired on by North Vietnamese naval forces.In the documentary film "The Fog of War",then-US Defense SecretaryRobert McNamaraconcedes the attack during the second incident did not happen, though he says that he and President Johnson believed it did so at the time.

The first Gulf of Tonkin Incident (2 August) should not be confused with the second Gulf of Tonkin Incident (4 August). The North Vietnamese claimed that on August 2, US destroyer USSMaddoxwas hit by one torpedo and that one of the American aircraft had been shot down in North Vietnamese territorial waters. The PAVN Museum in Hanoi displays "Part of a torpedo boat... which successfully chased away the USS Maddox August 2nd, 1964".

Thecasus bellifor the Vietnam War was the second incident. On August 4, USSMaddoxwas launched to the North Vietnamese coast to "show the flag" after the first incident. The US authorities claimed that two Vietnamese boats tried to attack USSMaddoxand were sunk. The government of North Vietnam denied the second incident completely. Deniability played favorably into the propaganda efforts of North Vietnam throughout the war, and for some years to follow.

1967 Arab-Israeli War

Acasus belliplayed a prominent role during theSix-Day Warof 1967. The Israeli government had a short list ofcasūs belli,acts that it would consider provocations justifying armed retaliation. The most important was a blockade of theStraits of Tiranleading intoEilat,Israel's only port to theRed Sea,through which Israel received much of its oil. After several border incidents between Israel andEgypt's alliesSyriaandJordan,Egypt expelledUNEFpeacekeepers from theSinai Peninsula,established a military presence atSharm el-Sheikh,and announced a blockade of the straits, prompting Israel to cite itscasus belliin opening hostilities against Egypt.

China-Vietnam War

During the 1979Sino-Vietnamese War,China's leaderDeng Xiaopingtold the United States that its plan to fight the Vietnamese was revenge for Vietnam'stopplingof theKhmer Rougeregime ofCambodia,an ally of China. However Chinese nationalists have argued that the realcasus belliwas Vietnam'spoor treatment of its ethnic Chinese population,as well as suspicion of Vietnam trying to consolidate Cambodia with Soviet backing.

2003 invasion of Iraq

Main article:Rationale for the Iraq War

February 5, 2003 – U.S. Secretary of StateColin Powellholding a model vial ofanthraxwhile giving the presentation to theUN Security Council.

When the United Statesinvaded Iraq in 2003,it cited Iraq's non-compliance with the terms of cease-fire agreement for the 1990–1991Gulf War,as well as planning in the1993 attempted assassinationof former PresidentGeorge H. W. Bushand firing on coalition aircraft enforcing theno-fly zonesas its statedcasus belli.

Cited by theGeorge W. Bush administrationwasSaddam Hussein'sweapons of mass destruction(WMD) program. The administration claimed that Iraq had not conformed with its obligation to disarm under past UN Resolutions, and that Saddam Hussein was actively attempting to acquire a nuclear weapons capability as well as enhance an existing arsenal of chemical and biological weapons. Secretary of StateColin Powelladdressed a plenary session of theUnited Nations Security Councilon February 5, 2003, citing these reasons as justification for military action.Since-declassified National Intelligence Estimates (NIE's) indicate that any certainty may have been overstated in justification of armed intervention; the extent, origin and intent of these overstatements cannot be conclusively determined from the NIE.

Annexation of Crimea

After theannexation of Crimea by the Russian Federationin 2014, Russian PresidentVladimir Putinargued that Crimea and other regions "were not part of Ukraine" after it was taken in the 18th century. The ethnic Russian population in Crimea and eastern Ukraine has been seen as acasus bellifor Russia's annexation.The Foreign Ministry claimed that Ukraine tried to seize Crimean government buildings, citing this as acasus belli.

2022 Russian Invasion of Ukraine

Prior to the2022 Russian invasion of Ukraine,Russia recognized the separatist republics inDonetskandLuhansk,and the alliance between them was ratified in their parliaments, thus creating a usablecasus belli.Russia also claimed agenocidewas being committed againstRussian speakersinUkrainebyneo-Nazigroups and that theUkrainian governmentwere neo-Nazis.A false-flag operation was also considered by Russia, according to US, UK, and Ukrainian intelligence.

2023 Israel–Hamas war

Main article:2023 Israel–Hamas war

On October 7, 2023,Palestinian militant groups,led byHamas,launched a major attackintoIsraeli territoryfrom theGaza Strip.This operation was called 'Operation Al-Aqsa Flood' by Hamas. In response, the Israel Defense Forces launched a counteroffensive, officially named 'Operation Iron Swords'.Following reports that Egypt had given Israel a three day heads-up that "something big" and "an explosion of the situation is coming",questions emerged about IDF's readiness,and whether Israel had ignored the information.

See also

• Casus foederis
• False flag
• Jus ad bellum
• List of Latin phrases
• Status quo

Literature

• Braumoeller, Bear F. (2019).Only the Dead: The Persistence of War in the Modern Age.Oxford: Oxford University Press. p. 288.ISBN9780190849542.
• Donald, David Herbert (5 November 1996).Lincoln.Simon & Schuster.ISBN978-0-684-82535-9.
• Holsti, Kalevi (1991).Peace and War: Armed Conflicts and International Order, 1648–1989.Cambridge: Cambridge University Press. p. 379.ISBN9780521399296.
• Slater S.J., Thomas (1925)."Book 6: On War".A manual of moral theology for English-speaking countries.Burns Oates & Washbourne Ltd.