A declaration of war is a formal act by which one state goes to war against another. The declaration is a performative speech act (or the signing of a document) by an authorized party of a national government, in order to create a state of war between two or more states.
The legality of who is competent to declare war varies between nations and forms of government. In many nations, that power is given to the head of state or sovereign. In other cases, something short of a full declaration of war, such as a letter of marque or a covert operation, may authorise war-like acts by privateers or mercenaries. The official international protocol for declaring war was defined in the Hague Convention (III) of 1907 on the Opening of Hostilities.
Since 1945, developments in international law such as the United Nations Charter, which prohibits both the threat and the use of force in international conflicts, have made declarations of war largely obsolete in international relations. The UN Security Council, under powers granted in articles 24 and 25, and Chapter VII of the Charter, may authorize collective action to maintain or enforce international peace and security. Article 51 of the United Nations (UN) Charter also states that: "Nothing in the present Charter shall impair the inherent right to individual or collective self-defence if an armed attack occurs against a state."
Few nations have formally declared war upon another since then. In addition to this, non-state or terrorist organizations may claim to or be described as "declaring war" when engaging in violent acts. These declarations may have no legal standing in themselves, but they may still act as a call to arms for supporters of these organizations.
The practice of declaring war has a long history. The ancient Sumerian Epic of Gilgamesh gives an account of it, as does the Old Testament. The Roman Republic formalized the declaration of war by a special ceremony, the ritual of the Fetials, though the practice started to decline into the Imperial era.
However, the practice of declaring war was not always strictly followed. In his study Hostilities without Declaration of War (1883), the British scholar John Frederick Maurice showed that between 1700 and 1870 war was declared in only 10 cases, while in another 107 cases war was waged without such declaration (these figures include only wars waged in Europe and between European states and the United States, not including colonial wars in Africa and Asia).
In modern public international law, a declaration of war entails the recognition between countries of a state of hostilities between these countries, and such declaration has acted to regulate the conduct between the military engagements between the forces of the respective countries. The primary multilateral treaties governing such declarations are the Hague Conventions.
The League of Nations, formed in 1919 in the wake of the First World War, and the General Treaty for the Renunciation of War of 1928 signed in Paris, France, demonstrated that world powers were seriously seeking a means to prevent the carnage of another world war. Nevertheless, these powers were unable to stop the outbreak of the Second World War, so the United Nations (UN) was established following that war in a renewed attempt to prevent international aggression through declarations of war.
In classical times, Thucydides condemned the Thebans, allies of Sparta, for launching a surprise attack without a declaration of war against Plataea, Athens' ally - an event that began the Peloponnesian War.
The utility of formal declarations of war has always been questioned, either as sentimental remnants of a long-gone age of chivalry or as imprudent warnings to the enemy. For example, writing in 1737, Cornelius van Bynkershoek judged that "nations and princes endowed with some pride are not generally willing to wage war without a previous declaration, for they wish by an open attack to render victory more honourable and glorious." Writing in 1880, William Edward Hall judged that "any sort of previous declaration therefore is an empty formality unless the enemy must be given time and opportunity to put himself in a state of defence, and it is needless to say that no one asserts such a quixotism to be obligatory."
In the first Hague Convention of 1899, the signatory states agreed that at least one other nation be used to mediate disputes between states before engaging in hostilities:
In case of serious disagreement or conflict, before an appeal to arms, the signatory Powers agree to have recourse, as far as circumstances allow, to the good offices or mediation of one or more friendly Powers.
The Hague Convention (III) of 1907 called "Convention Relative to the Opening of Hostilities" gives the international actions a country should perform when opening hostilities. The first two Articles say:
In 1989, Panama declared itself to be in a state of war with the United States. On 13 May 1998, at the outbreak of the Eritrean-Ethiopian War, Ethiopia, in what Eritrean radio described as a "total war" policy, mobilized its forces for a full assault against Eritrea. The Claims Commission found that this was in essence an affirmation of the existence of a state of war between belligerents, not a declaration of war, and that Ethiopia also notified the United Nations Security Council, as required under Article 51 of the UN Charter.
Declarations of war, while uncommon in the traditional sense, have mainly been limited to the conflict areas of the Western Asia and East Africa since 1945. Additionally, some small states have unilaterally declared war on major world powers such as the United States, United Kingdom, or Russia when faced with a hostile invasion and/or occupation.
This is a list of declarations of war (or the existence of war) by one sovereign state against another since the end of World War II in 1945. Only declarations that occurred in the context of a direct military conflict are included.
|Arab-Israeli War (1948-49)||15 May 1948||declaration of war||Egypt||Israel||26 March 1979|||
|Suez Crisis (1956)||Jordan||26 October 1994|
|Six-Day War (1967)||Syria||Still at war|
|War of Attrition (1967-70)||Iraq|
|Yom Kippur War (1973)||Lebanon|
|Ogaden War||13 July 1977||Somalia||Ethiopia||15 March 1978|
|Uganda-Tanzania War||2 November 1978||Tanzania||Uganda||3 June 1979|||
|Iran-Iraq War||22 September 1980||Iraq||Iran||20 July 1988|||
|United States invasion of Panama||15 December 1989||existence of a state of war||Panama||United States||31 January 1990|||
|Eritrean-Ethiopian War||14 May 1998||Ethiopia||Eritrea||12 December 2000|||
|Chadian Civil War (2005-10)||23 December 2005||Chad||Sudan||15 January 2010|||
|Djiboutian-Eritrean border conflict||13 June 2008||Djibouti||Eritrea||6 June 2010|||
|Russo-Georgian War||9 August 2008||declaration of war (declaring the existence of a state of war.)||Georgia||Russia||16 August 2008|||
|Heglig Crisis||11 April 2012||existence of a state of war||Sudan||South Sudan||26 May 2012|||
|Sinai insurgency||1 July 2015||Egypt||Islamic State||Still at war|||
|2020 Nagorno-Karabakh conflict||27 September 2020||Azerbaijan||Armenia||10 November 2020|||
|2020 Western Saharan clashes||14 November 2020||declaration of war||SADR||Morocco||Still at war|||
The United Nations Charter is the foundation of modern international law. The UN Charter is a treaty ratified by members of the UN, which are therefore legally bound by its terms. Article 2(4) of the UN Charter generally bans the use of force by states except when carefully circumscribed conditions are met, stating:
All members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the purposes of the United Nations.
This rule was "enshrined in the United Nations Charter in 1945 for a good reason: to prevent states from using force as they felt so inclined", said Louise Doswald-Beck, Secretary-General International Commission of Jurists.
Therefore, in the absence of an armed attack against a country or its allies, any legal use of force, or any legal threat of the use of force, has to be supported by a United Nations Security Council resolution authorizing member states to use force.
In an effort to force nations to resolve issues without warfare, framers of the United Nations Charter attempted to commit member nations to using warfare only under limited circumstances, particularly for defensive purposes.
The UN became a combatant itself after North Korea invaded South Korea on 25 June 1950, which begun the Korean War. The UN Security Council condemned the North Korean action by a 9-0 resolution (with the Soviet Union absent) and called upon its member nations to come to the aid of South Korea. The United States and 15 other nations formed a "UN force" to pursue this action. In a press conference on 29 June 1950, U.S. President Harry S. Truman characterized these hostilities as not being a "war" but a "police action".
The United Nations has issued Security Council Resolutions that declared some wars to be legal actions under international law, most notably Resolution 678, authorizing the 1991 Gulf War which was triggered by Iraq's invasion of Kuwait. UN Resolutions authorise the use of "force" or "all necessary means".
The examples and perspective in this article deal primarily with Western culture and do not represent a worldwide view of the subject. (January 2016)
Throughout the Commonwealth realms (the UK, Australia, Canada, et al.) the formal right to declare war rests with the monarch, currently Elizabeth II, or their representative (the governor-general), as part of the royal prerogative and exercised by the Prime Minister (for example in the UK) or that realm's written constitution. It is a very recent development in the United Kingdom that parliamentary approval be sought before deployment of combat forces overseas, for example in the Iraq War (2003) and airstrikes on Daesh (ISIL), but this is not a legal requirement.
Article 171 of the Albanian Constitution says that the President can declare war at the request of the Council of Ministers. The Assembly can also declare war on the proposal of the President.
According to Article 75 of the Argentine Constitution, the Congress has the power to declare war.
Article 118 of the Armenian Constitution allows the National Assembly to declare war and make peace with a majority vote among the parliamentarians. It proceeds to specify that the body shall determine the matter of declaring a state of war if it is unable to convene.
Article 38 of the Austrian Constitution states that the National Council and the Federal Council convene to adopt war declarations.
According to Article 84 of Brazilian Constitution, the President of Brazil has the power to declare war, in the event of foreign aggression, when authorized by the National Congress or, upon its ratification if the aggression occurs between legislative sessions, and decree full or partial national mobilization under the same conditions.
According to Article 32 of the Chilean Constitution, declaring war is a special power of the President of the Republic.
Article 62 of the Chinese Constitution states that the National People's Congress has the authority to decide any questions of both war and peace.
According to Article 173 of the Colombian Constitution, the Senate can declare war.
Part III of the Danish Constitution says that the King can use military force against the any other nation-state without the consideration of the Folketing--the Danish legislature--on the condition that he submits the motion to the body. If the Folketing is not in session at the time when the King utilizes this power, then it shall be convoked immediately.
According to Article 152 of the Egyptian Constitution, the President of the Republic is the Supreme Commander of the Armed Forces. Despite this role, the President is unable to declare war without consulting both the National Defense Council and the House of Representatives for approval. In the case of the House of Representatives, a two-thirds majority vote is required.
Article 55 of the Ethiopian Constitution says that a state of war can be proclaimed by the legislature after a draft law is submitted by the Council of Ministers to it.
According to Article 62 of the Georgian Constitution, Parliament can reach a determination on the matter of declaring war with a majority among the legislative members.
Article 115a of Basic Law for the Federal Republic of Germany says that, unless attacked by an opposing military force, Germany must vote a two-thirds majority vote in the Bundestag if the federal republic is under the threat of war.
According to Article 36 of the Greek Constitution, the President can declare war.
Article 1 of the Hungarian Constitution states that the Parliament has the power to declare war and make peace.
According to Article 11 of the Indonesian Constitution, the President can declare war and make peace with the approval of People's Representative Council--one of two chambers in the Indonesian legislature.
The Icelandic Constitution is silent on the matters of declaring war and making peace.
According to Article 110 of the Iranian Constitution, the Leadership Council is responsible for both declaring war and making peace as well as mobilizing the armed forces.
According to Article 61 of the Iraqi Constitution, the Council shall approve any war declarations.
Article 28.3.1° of the Irish Constitution states that "war shall not be declared and the State shall not participate in any war save with the assent of Dáil Éireann." Ireland has taken a policy of non-alignment (what many confuse with neutrality see: Irish Neutrality) in military terms and is thus not a member of North Atlantic Treaty Organization (NATO).
The Basic Laws of Israel says that declaring war can only be made in pursuant to a governmental decision.
According to the 11° Article of the Italian Constitution, Italy rejects war as an instrument of aggression. Parliament has the power to declare war if it is necessary to create an order that ensures peace and justice among Nations; the most reliable authors exclude that among the circumstances in which it can be declared the state of war under Article 78 of the Constitution may be included also the state of civil war within the country.
According to Article 9 of the Japanese Constitution, the country is prohibited from engaging in war. This has been interpreted as including the declaration of war. However, in 2014, this portion of the constitution was reinterpreted by a constitutional amendment to allow a degree of leeway to the Japan Self-Defense Forces in order to fulfill the country's obligations as prescribed by its diplomatic relations.
Article 33 of Jordanian Constitution states that the King declares war and makes peace.
Article 65 of the Lebanese Constitution says that executive power is vested in the Council of Ministers and the Armed Forces are subject to that authority. Of the powers that are listed in that section, one of them is declaring war.
The Malaysian Constitution states that declaring war is a legislative matter.
According to Article 89 § VIII of the Mexican Constitution, the President may declare war in the name of the United Mexican States after the correspondent law is enacted by the Congress of the Union.
According to Article 49 of the Moroccan Constitution lists declaring war as a matter to be deliberated by the Council of Ministers.
The Norwegian Constitution is silent on the matters of declaring war and making peace.
Article 144 of the Paraguayan Constitution renounces war, but it also asserts the "principle of legitimate defense."
According to Article 118 of the Peruvian Constitution, the President of the Republic can declare war and sign peace treaties with the authorization of Congress.
Section 23 of the Filipino Constitution says that the Congress shall decide on the matter of declaring war.
According to Article 116 of the Polish Constitution, the Sejm--the Polish legislature--has the power to declare war.
Article 161 of the Portguese Constitution says that Assembly of the Republic is responsible for declaring war.
Article 71 of the Russian Constitution states that there is an authority to declare war, but it does not expressly state what entity can perform this action. In Article 106, however, it states that the Duma--the Russian legislature--has the jurisdiction to declare war and make peace.
Article 61 of the Saudi Constitution states that declaring war is a matter for the King.
The Serbian Constitution says that the National Assembly is responsible for declaring war. According to Article 106, upon declarations of war or emergency, the National Assembly shall be convoked without announcement.
According to 2010:1408 15 kap. 14 § entitled "Krigsförklaring" (declaration of war) the Swedish cabinet (regeringen) may not declare Sweden to be at war without the parliaments (riksdagen) consent unless Sweden is first attacked.
Section 177 of the Thai Constitution states that, with the approval of the National Assembly, declaring war is a "royal prerogative" of the King.
According to Article 87 of the Turkish Constitution, the Grand National Assembly has the authority to declare war.
In the United States, Congress, which makes the rules for the military, has the constitutional to "declare war". However neither the U.S. Constitution nor any Act of Congress stipulate what format a declaration of war must take. War declarations have the force of law and they are intended to be executed by the President as "commander in chief" of the armed forces. This is a power that has been unevenly performed by the federal government as many as eleven times across five armed conflicts: the War of 1812, the Mexican-American War, the Spanish-American War, World War I, and World War II. Of those five, World War I and World War II were the only ones in which the United States issued more than one declaration of war. The last time Congress passed joint resolutions saying that a "state of war" existed was on June 5, 1942, when the U.S. issued three war declarations on Bulgaria, Hungary, and Romania. Since then, the US has used the term "authorization to use military force," as in the case against Iraq in 2003.
Sometimes decisions for military engagements were made by US presidents, without formal approval by Congress, based on UN Security Council resolutions that do not expressly declare the UN or its members to be at war. Part of the justification for the United States invasion of Panama was to capture Manuel Noriega (as a prisoner of war) because he was declared a criminal rather than a belligerent.
In response to the September 11 attacks, the United States Congress passed the joint resolution Authorization for Use of Military Force Against Terrorists on September 14, 2001, which authorized the US President to fight the War on Terror.
Article 85 of the Uruguayan Constitution says that the General Assembly is "competent to declare war."
The Venezuelan Constitution does not expressly state the power to declare war. According to Article 187 of it, however, the National Assembly has the power "to authorize the operation of Venezuelan military missions abroad or foreign military missions within the country." This can be interpreted as the power to propose a declaration of war.
Article 70 of the Vietnamese Constitution lists deciding on "issues of war and peace" as a legislative subject for the National Assembly.
Developments in international law since 1945, notably the United Nations (UN) Charter, including its prohibition on the threat or use of force in international relations, may well have made the declaration of war redundant as a formal international legal instrument (unlawful recourse to force does not sit happily with an idea of legal equality).