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 law recognizes 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 byThucydides in 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).[citation needed]
Countries may think they need a public justification for attacking another country, both to galvanize internal support for the war and to gain the support of potential allies.[citation needed]
Bear Braumoeller (2019) stated: "However idiosyncratic thecasus belli may 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.[10] 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".[11]
InThe Causes of War (1972), Australian historianGeoffrey Blainey mentioned 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.[10]
Theodore K. Rabb andRobert I. Rotberg explored 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).[10]
Kalevi Holsti catalogued and categorised wars from 1648 to 1989 according to 24 categories of "issues that generated wars".[12][10]
Acasus belli intentionally based on inaccurate facts is known as apretext.
Europeans had access to Chinese ports as outlined in theTreaty of Nanking from theFirst Opium War. France used the execution ofAuguste Chapdelaine as acasus belli for 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).[13][14]
While long-term conflict between theNorthern andSouthern 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 as thecasus belli for theUnion.[15] 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."[16] Confederate veteranWilliam Watson opined in 1887 that up until that point, U.S. Secretary of StateWilliam H. Seward had not been able to find 'a just cause to declare war against the seceded States', but Sumter gave him 'thecasus belli he had sought'.[15] Watson lamented howJefferson Davis and 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'.[15]
Cartoon of belligerentUncle Sam placing Spain on notice, c. 1898
TheMaine was a United States Navy ship that sank inHavana Harbor,Spanish Cuba on February 15, 1898. While the destruction of theMaine did not result in an immediate declaration of war with Spain, it did create an atmosphere that precluded a peaceful solution.[17] 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. TheMcKinley administration 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.[18] Advocates of war used the rallying cry, "Remember theMaine! To hell with Spain!"[19][20]
Austria-Hungary'scasus 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 whomurderedArchduke Franz Ferdinand of Austria atSarajevo. The Serbian government refused the Austrian Démarche, and Austria-Hungary declared war.[21]
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.[citation needed]
In 1917, the German Empire sent theZimmermann Telegram to 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 Wilson then 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.[22]
In his autobiographyMein Kampf,Adolf Hitler had in the 1920s advocated a policy ofLebensraum ("living space") for theGerman people, which in practical terms meant German territorial expansion into Eastern Europe.[23]In August 1939, to implement the first phase of this policy,Nazi Germany's government under Hitler's leadership staged theGleiwitz incident, which was used as acasus belli for theinvasion of Poland the following September. Nazi forces usedconcentration camp prisoners posing as Poles on 31 August 1939, to attack the German radio station Sender Gleiwitz in Gleiwitz, Upper Silesia, Germany (nowGliwice, Poland) on the eve of World War II. Poland's allies, theUnited Kingdom andFrance, subsequently declared war on Germany in accordance with their alliance.[citation needed] TheUnited States would declare war onJapan after theattack on Pearl Harbor on December 7, 1941.
Many historians have suggested that the SecondGulf of Tonkin incident was a manufactured pretext for theVietnam War. North Vietnamese Naval officials have publicly stated that during the second incident theUSS Maddox was never fired on by North Vietnamese naval forces.[24][25] In the documentary filmThe Fog of War, then-US Defense SecretaryRobert McNamara concedes the attack during the second incident did not happen, though he says that he and President Johnson believed it did so at the time.[26]
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 2 August, US destroyer USSMaddox was 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".[27]
Thecasus belli for the Vietnam War was the second incident. On 4 August, USSMaddox was 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 USSMaddox and were sunk. The government of North Vietnam denied the second incident completely.
Acasus belli played a prominent role during theSix-Day War of 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 Tiran leading intoEilat, Israel's only port to theRed Sea, through which Israel received much of its oil. After several border incidents between Israel andEgypt's alliesSyria andJordan, Egypt expelledUNEF peacekeepers from theSinai Peninsula, established a military presence atSharm el-Sheikh, and announced a blockade of the straits, prompting Israel to cite itscasus belli in opening hostilities against Egypt.[citation needed]
Cited by theGeorge W. Bush administration wasSaddam Hussein'sweapons of mass destruction (WMD) program and his connections toal-Qaeda after theSeptember 11 attacks in 2001. 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 Council on February 5, 2003, citing these reasons as justification for military action.[31] 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.[32]
After theannexation of Crimea by the Russian Federation in 2014, Russian PresidentVladimir Putin argued 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 belli for Russia's annexation.[33] The Foreign Ministry claimed that Ukraine tried to seize Crimean government buildings, citing this as acasus belli.[34]
Prior to the2022 Russian invasion of Ukraine, Russia recognized the separatist republics inDonetsk andLuhansk, and the alliance between them was ratified in their parliaments, thus creating a usablecasus belli.[35] Russia also claimed agenocide was being committed againstRussian speakers inUkraine byneo-Nazi groups and that theUkrainian government were neo-Nazis.[36] A false-flag operation was also considered by Russia, according to US, UK, and Ukrainian intelligence.[37]
^Reilly, John C.; Scheina, Robert L. (1980).American Battleships 1886–1923: Predreadnought Design and Construction. Annapolis, Maryland: Naval Institute Press. p. 30.ISBN978-0-87021-524-7.
^Jons, O. P. (March 2005).Remember the "MAINE". Maritime Heritage and Modern Ports. Second International Conference on Maritime Heritage and the Fourth International Conference on Maritime Engineering, Ports and Waterways. WIT Press. pp. 133–142. Archived fromthe original on 12 May 2009. Retrieved11 February 2008 – via U.S. Department of Transportation: National Transportation Library.
