World Library  
Flag as Inappropriate
Email this Article

Casus belli

Article Id: WHEBN0000178904
Reproduction Date:

Title: Casus belli  
Author: World Heritage Encyclopedia
Language: English
Subject: Waterloo Campaign: peace negotiations, Origins of the Six-Day War, Aegean dispute, Burmese–Siamese War (1765–67), Anglo-Zulu War
Collection: Causes of War, Latin Legal Terms, Laws of War
Publisher: World Heritage Encyclopedia

Casus belli

Casus belli is a Latin expression meaning "An act or event that provokes or is used to justify war".[1] Casus is a 4th declension masculine noun. Related to the English word "case", casus can mean "case", "incident", or "rupture". Belli is the genitive singular case of bellum, belli, a neuter noun of the 2nd declension. Belli means of war. A nation's casus belli involves direct offenses or threats against it, whereas a nation's casus foederis involves offenses or threats to an ally nation or nations—usually one with which it has a mutual defense pact, such as NATO.[2][3] Either may be considered an act of war.

The term came into wide use in the seventeenth and eighteenth centuries through the writings of Hugo Grotius (1653), Cornelius van Bynkershoek (1707), and Jean-Jacques Burlamaqui (1732), among others, and due to the rise of the political doctrine of jus ad bellum or "just war theory".[4][5] The term is also used informally to refer to any "just cause" a nation may claim for entering into a conflict. It is used retrospectively to describe situations that arose before the term came into wide use, as well as being used to describe present-day situations—even those in which war has not been formally declared.

In formally articulating a casus 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 (ultima ratio) and that it has "just cause" for doing so. Modern international law recognizes only three lawful justifications for waging war: self-defense, defense of an ally required by the terms of a treaty, and approval by the United Nations.

Proschema (plural proschemata) is the equivalent Greek term, first popularized by Thucydides in his History 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 called prophasis (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 1
  • Historical examples 2
    • American Civil War 2.1
    • Spanish–American War 2.2
    • World War I 2.3
    • World War II 2.4
    • Six-Day War 2.5
    • Vietnam War 2.6
    • 1982 Israeli invasion of Lebanon 2.7
    • War on Terror 2.8
    • 2003 Invasion of Iraq 2.9
  • See also 3
  • References 4
  • Books 5

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 the post-World-War-II era, the UN Charter prohibits 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 on wars of aggression.

Historical examples

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

American Civil War

While the causes for the lead up to the American Civil War were numerous, the Confederate attack on Fort Sumter (April 12–14, 1861) served as casus belli[6] for igniting the deadliest war in American history.

Spanish–American War

In the eyes of the United States, the sinking of the USS Maine provided casus belli for the Spanish–American War. There have been several alternative explanations for the explosion, such as that proposed by Mr. Evans, a senior editor of Newsweek. In his book, he identifies a flaw in the design of the USS Maine whereby the boiler room stood right next to the gunpowder storage room and that a boiler malfunction may have heated the adjacent metal wall and caused the powder to explode.

World War I

The assassination of Archduke Franz Ferdinand of Austria provided the trigger that led to the outbreak of World War I. In June 1914, the refusal of two points of the July Ultimatum offered to Serbia was used by Austria-Hungary as a casus belli for declaring war on Serbia. The murder at Sarajevo in Bosnia by Gavrilo Princip, a Bosnian Serb nationalist, Austrian subject and member of Young Bosnia (a secret society), was the reason why this ultimatum was made.

The Russian Empire started to mobilize its troops in defense of its ally Serbia, which resulted in the German Empire declaring war on Russia in support of its ally Austria-Hungary. Very quickly, after the involvement of France, the Ottoman Empire and the British Empire, five of the six great European powers became involved in the first European general war since the Napoleonic Wars.

In 1917, the German Empire sent the Zimmermann Telegram to Mexico, in which they tried to convince 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, the relayed to the U.S. Woodrow Wilson used 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 multiple reasons.

World War II

In his autobiography Mein Kampf, Adolf Hitler had in the 1920s advocated a policy of lebensraum ("living space") for the German people, which in practical terms meant German territorial expansion into Eastern Europe.

Gleiwitz incident on the orders of Heydrich.

In August 1939, to implement the first phase of this policy, Germany's Nazi government under Hitler's leadership staged the Gleiwitz incident, which was used as a casus belli for the invasion of Poland the following September. Nazi forces used concentration camp prisoners posing as Poles on 31 August 1939, to attack the German radio station Sender Gleiwitz in Gleiwitz, Upper Silesia, Germany (since 1945: Gliwice, Poland) on the eve of World War II in Europe. Poland's allies, the UK and France, subsequently declared war on Germany in accord their alliance.

In 1941, acting once again in accordance with the policy of lebensraum, Nazi Germany invaded the Soviet Union, using the casus belli of pre-emptive war to justify the act of aggression.

The Soviet Union also employed a manufactured casus belli against Finland during World War II on its part. In November 1939, shortly after the outbreak of hostilities between Germany, Britain and France, the Soviet Union staged the shelling of the Russian village of Mainila, which it blamed on the Finns. This manufactured incident was then used as a casus belli for the Winter War. In 1998, Russian President Boris Yeltsin admitted that the invasion had in fact constituted a Soviet war of aggression.

Six-Day War

A casus belli played a prominent role during the Six-Day War of 1967. The Israeli government had a short list of casūs belli, acts that it would consider provocations justifying armed retaliation. The most important was a blockade of the Straits of Tiran leading into Eilat, Israel's only port to the Red Sea, through which Israel received much of its oil. After several border incidents between Israel and Egypt's allies Syria and Jordan, Egypt expelled UNEF peacekeepers from the Sinai Peninsula, established a military presence at Sharm el-Sheikh, and announced a blockade of the straits, prompting Israel to cite its casus belli in opening hostilities against Egypt.

Vietnam War

Many historians have suggested that the Gulf of Tonkin Incident was a manufactured pretext for the Vietnam War. North Vietnamese Naval officials have publicly stated that the USS Maddox was never fired on by North Vietnamese naval forces.[7][8] In the documentary film "The Fog of War", then-US Defense Secretary Robert McNamara concedes the attack did not happen, though he says that he and President Johnson believed it did so at the time.[9]

Some people confuse the first Gulf of Tonkin Incident (the 2nd of August) and the second Gulf of Tonkin Incident (the 4th of August). The North Vietnamese claimed that on August 2, US destroyer USS Maddox 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, [sic] 2nd 1964".

The casus belli for the Vietnam War was the second incident. On August 4, USS Maddox 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 USS Maddox and 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.

1982 Israeli invasion of Lebanon

The casus belli cited by Israel for its June 1982

  • Vidal, Gore. Imperial America: Reflections on the United States of Amnesia. Hardcover ed. Avalon Group.


  1. ^ casus belliThe Free Dictionary:
  2. ^  
  3. ^  
  4. ^ Russell, Frederick H. (1997). The Just War in the Middle Ages.  
  5. ^  
  6. ^ Watson, William (1887). Life in the Confederate Army: Being the Observations and Experiences of an Alien in the South During the American Civil War. United States: Chapman & Hall. p. 113. Retrieved August 5, 2014. 
  7. ^ "McNamara asks Giap: What happened in Tonkin Gulf?". (November 9, 1995). Associated Press
  8. ^ CNN Cold War - Interviews: Robert McNamara, retrieved January 23, 2007
  9. ^
  10. ^ Sachar, Howard M.: A History of Israel from the Rise of Zionism to Our Time, Alfred A. Knopf 1996, ISBN 0-679-76563-8, page 904.
  11. ^ "As early as January 1982, therefore, with Begin's approval, Sharon paid a secret visit to Beirut.... By the following month... operational plans for the offensive were well advanced. Israeli liaison officers repeatedly visited Beirut to coordinate strategy with the Phalange. In the end, the Lebanon expedition would be the most thoroughly prepared campaign in Israel's history." - Sachar, A History of Israel, p. 903.
  12. ^
  13. ^


See also

Cited by the Saddam Hussein's weapons 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 State Colin Powell addressed a plenary session of the United Nations Security Council on February 5, 2003 citing these reasons as justification for military action.[13]

When the United States no-fly zones as its stated casus belli.[12]

2003 Invasion of Iraq

The casus belli for the Bush administration's conceptual War on Terror, which resulted in the 2001 Afghanistan war, was the September 11 attacks in 2001 on the World Trade Center in New York City, The Pentagon in Arlington, Virginia, and the intended attack on the United States Capitol in Washington, D.C.

War on Terror

[11] A possible invasion plan had been prepared in advance by Israel.[10]

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.