Casus belli is a Latin expression meaning the justification for acts of war. Casus means "incident", "rupture" or indeed "case", while belli means bellic ("of war"). It is usually distinguished from casus foederis, where casus belli refers to offenses or threats directly against a nation, and casus foederis refers to offenses or threats to another, allied, nation with which the justifying nation is engaged in a mutual defense treaty, such as NATO.^[1][2]

The term came into wide usage in the seventeenth and eighteenth centuries with the writings of Hugo Grotius (1653), Cornelius van Bynkershoek (1707), and Jean-Jacques Burlamaqui (1732), among others, and the rise of the political doctrine of jus ad bellum or "just war theory".^[3][4] Informal usage varies beyond its technical definition to refer to any "just cause" a nation may claim for entering into a conflict. As such, it has been used both retroactively to describe situations in history before the term came into wide usage and in the present day when describing situations when war has not been formally declared.

Formally, a government would lay out its reasons for going to war, as well as its intentions in prosecuting it and the steps that might be taken to avert it. In so doing, the government would attempt to demonstrate that it was going to war only as a last resort (ultima Ratio) and that it in fact possessed "just cause" for doing so. In theory international law today allows only three situations as legal cause to go to war: out of self-defense, defense of an ally under a mutual defense pact, or sanctioned by the UN.

Proschema (plural proschemata) is the Greek equivalent term. The stated reasons may or may not be the actual reason for waging the war (prophasis, πρὸφασις). The term was first popularized by Thucydides in his History of the Peloponnesian War, who identified fear, honor, and interest as the three primary real reasons that wars are waged, while proschemata commonly play up nationalism or fearmongering (as opposed to rational or reasonable fears).

Reasons for use [link]

Countries need a public justification for attacking another country. This justification is needed to galvanize internal support for the war, as well as gain the support of potential allies.

In the post World War Two era, the UN Charter prohibits signatory countries from engaging in war except 1) as a means of defending themselves against aggression, or 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 which embark on wars of aggression.^{[citation needed]} In effect, this means that countries in the modern era must have a plausible casus belli for initiating military action, or risk UN sanctions or intervention.^{[improper synthesis?]}

Historical examples [link]

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

Spanish-American War [link]

The casus belli for the Spanish-American War was the sinking of the USS Maine.

There have been several alternative explanations to the explosion such as that proposed by Mr. Evans, the senior editor of Newsweek. In his book, he states that the USS Maine was designed incorrectly because the boiler room was right next to the gunpowder storage room and that an overheating in the boiler room may have heated the adjacent metal wall, causing the powder to explode.^{[citation needed]}

World War I [link]

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

The Russian Empire started to mobilise its troops in defence 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.

World War II [link]

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.

In August 1939, in order 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. Poland's allies, the UK and France, honoured their alliance and subsequently declared war on Germany.

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 [link]

A casus belli played a prominent role during the Six-Day War of 1967. The Israeli government had a short list of casūs bellorum, 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 [link]

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.^[5][6] In the movie "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.^[7]

Some people^[who?] 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 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 in order to "show the flag" after the first incident. The U.S. 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 [link]

The casus belli cited by Israel for its June 1982 invasion of Lebanon was the attempted assassination of the Israeli Ambassador in London, which the Israeli government blamed on the Palestinian Liberation Organization.^[8] A possible invasion plan had been prepared in advance by Israel.^[9]

Greece and Turkey [link]

In 1995, The Turkish Parliament issued a casus belli against Greece in reaction to an enacted extension of Greek territorial waters from 6 nautical miles (11 km) to 12 nautical miles (22 km) from the coast.^[10]

War on Terror [link]

The casus belli for the Bush administration's conceptual War on Terror, which resulted in the 2001 Afghanistan war and the 2003 Iraq war, was the September 11 attacks in 2001 on the World Trade Center in New York City, The Pentagon in Arlington, Virginia and the apparently intended attack on the United States Capitol in Washington, D.C.^{[citation needed]}

2003 Invasion of Iraq [link]

When the United States invaded Iraq in 2003, it cited Iraq's non-compliance with the terms of cease-fire agreement for the 1990-1991 Gulf War, as well as planning in 1993 attempted assassination of former President George H. W. Bush and firing on coalition aircraft enforcing the no-fly zones as its stated casus belli.^[11]

Cited by the George W. Bush administration was 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.^[12] It has subsequently been found that there were no weapons of mass destruction found in Iraq after the war.

See also [link]

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

References [link]

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