A declaration of war is a formal act by which one state announces existing or impending war activity against another. The declaration is a performative speech act (or the public 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, though such declarations may have relevance within the domestic law of the belligerents or of neutral nations. 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 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."
Declarations of war have been exceedingly rare since the end of World War II. Scholars have debated the causes of the decline, with some arguing that states are trying to evade the restrictions of international humanitarian law (which governs conduct in war) while others argue that war declarations have come to be perceived as markers of aggression and maximalist aims.
History
The practice of declaring war has a long history. The ancient Sumerian Epic of Gilgamesh gives an account of it,Brien Hallett, The Lost Art of Declaring War, University of Illinois Press, 1998, , pp. 65f. as does the Old Testament.Deut. 20:10–12, Judg. 11:1–32.Brien Hallett, The Lost Art of Declaring War, University of Illinois Press, 1998, , pp. 66f. 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, e.g. the 1812 French declaration of war on Russia or the Declarations of war by Great Britain and the United Kingdom, 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 was established following that war in a renewed attempt to prevent international aggression through declarations of war.
Denigration of formal declarations of war before WWI 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.Thucydides. History of the Peloponnesian War, Book II.
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."Bynkershoek, Cornelius van. 1930. Quæstionum Juris Publici Liber Duo (1737). Trans. Tenney Frank. The Classics of International Law No. 14 (2). Publications of the Carnegie Endowment for International Peace. Oxford at the Clarendon Press. (I, ii, 8). 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."Hall, William Edward. 1924. A Treatise on International Law. 8th ed. by A. Pearce Higgins. London: Humphrey Milford: Oxford University Press. (p. 444).
Formal declarations of war during World War I
Formal declarations of war during World War II
Declared wars since 1945 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 or Russia when faced with a hostile invasion and/or occupation. The following 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.
War(s) Date Titled Belligerents Ended References Declaring party Opponent 15 May 1948 Declaration of war Egypt 26 March 1979 26 October 1994 Syria, Iraq, Still technically at war.India–Pakistan war of 19656 September 1965Existence of a state of war23 September 1965Six-Day War (1967)June 1967Mauritania1991India–Pakistan war of 197123 November 197116 December 1971 Uganda–Tanzania War 2 November 1978Declaration of war 3 June 1979 Iran–Iraq War 22 September 1980 Iraq 20 July 1988 United States invasion of Panama 15 December 1989 Existence of a state of war 31 January 1990 Eritrean–Ethiopian War 14 May 1998 12 December 2000 World: Africa Eritrea: 'Ethiopia pursues total war'. BBC News. 6 June 1998.NATO intervention in Kosovo24 March 199925 June 1999 Chadian Civil War 23 December 2005 15 January 2010 Djiboutian–Eritrean border conflict 13 June 2008 6 June 2010 Russo-Georgian War 9 August 2008 16 August 2008 Heglig Crisis 11 April 2012 26 May 2012 Korean conflict (Frozen)30 March 2013Still technically at war.2016 Nagorno-Karabakh conflict08 August 2014 Second Nagorno-Karabakh War 27 September 2020 10 November 2020 Second Western Sahara War 14 November 2020 Declaration of war Still at war. Gaza war 7 October 2023 Existence of a state of war HamasStill at war.
Other unique cases
Russo-Ukrainian War No formal declaration of war has been issued in the ongoing Russo-Ukrainian War. At the beginning of the Russian invasion of Ukraine, Putin gave a televised broadcast announcing the start of the invasion with the term "special military operation", side-stepping a formal declaration of war. The statement was, however, regarded as a declaration of war by the Ukrainian government and reported as such by many international news sources. While the Ukrainian parliament refers to Russia as a "terrorist state" in regards to its military actions in Ukraine, it has not issued a formal declaration of war on its behalf.
Procedures In Title II, Article 2 of 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:
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:
The United Nations and war 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 began 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, US 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 United Nations Security Council – Its Role in the Iraq Crisis: A Brief Overview.
Legality 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. 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, though such declarations may have relevance within the domestic law of the belligerents or of neutral nations. 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 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."
Requirements by country Declaring war is usually done through a process that involves prior approval before a formal announcement is made. This differs by country as some do not have a formal or codified pre-approval process, and in such a case, a given head of government can declare war with no pre-conditions.
Country War declarer Legal cause Authorized by Additional information Australia Governor-General Section 61 and 68 of the Australian constitution Governor-General (de jure)