A declaration of independence is a proclamation of the independence of a newly formed or reformed country from part or the whole of the territory of another, or a document containing such a declaration. Declarations of independence are generally made by one side without the consent of the previous government, and hence are often called unilateral declaration of independence or UDI.
In international law, unilateral declarations of independence are generally frowned upon, since preservation of territory is one of the few things that the countries of the world universally agree on. Declaring independence or supporting such a declaration is seen as a hostile act, that may easily lead to war.
Many states have come into being through an act of UDI. The legality of a UDI is often the subject of debate and unsurprisingly the previous government typically asserts that a UDI is illegal. Often, international bodies and other countries decline at first to accept the legitimacy of the declared state and its government. If the declared state becomes a functioning entity, it may gain diplomatic recognition over time and a form of backdated legitimacy. Not all such declarations result in actual states and those governments that do result from UDIs do not always survive and are often rivaled by the previous government. A significant number of unilaterally declared governments collapse or otherwise give way, with control returning to the previous government or shifting to a new follow-on government.
The first known formal declaration of independence was the Declaration of Arbroath in which Scottish leaders declared Scotland's independence from England on behalf of the Scottish people in 1320.
The United States Declaration of Independence was made by 13 of Britain's American colonies in 1776. In 1778, the Treaty of Alliance and the Treaty of Amity and Commerce were signed by the United States and France signaling the first official recognition of the new country. The Kingdom of Great Britain formally recognized the new country following the Treaty of Paris in 1783.
The Irish Republic was declared by Dáil Éireann in 1919; it never received international recognition, was rivaled by the administration of the Lord Lieutenant of Ireland during the Anglo-Irish War, and was ultimately superseded by the Irish Free State.
Indonesia declared independence from the Netherlands on August 17, 1945, which was soon recognized by the United States and Australia, but not by the Netherlands until 1949.
Katanga, a former a province of Belgian Congo, broke away with an UDI in 1960, when Congo was granted its independence. The attempted break away ended by the implementation of a UN supervised National Conciliation Plan in January 1963.
Rhodesia (Ian Smith's white minority government) declared UDI from the United Kingdom in 1965. Few states accepted its legitimacy. The UDI Rhodesian state was ultimately replaced under the Lancaster House Agreement by a restored British regime under a governor, Lord Soames. Within a short time, a new much more-widely recognized independent state, Zimbabwe, came into existence.
Guinea Bissau, formerly Portuguese Guinea, declared independence from Portugal in 1973, which was recognized by many countries, before Portugal formally granted independence in 1974.
East Timor, formerly Portuguese Timor, declared independence from Portugal on November 28, 1975, which was recognized by several countries including China, but not by neighboring Australia, or by Indonesia, which invaded on December 7 1975, and annexed it as its '27th province' on July 17, 1976.
The Turkish Republic of Northern Cyprus was proclaimed in Northern Cyprus, in 1983. The area had been occupied by Turkish forces since a Turkish invasion in 1974 and has only received international recognition from Turkey.
The Palestinian Liberation Organization unilaterally proclaimed the State of Palestine in 1988. The PLO had no control of any territory at the time.
Other nations, or aspiring nations, which have made formal declarations of independence, include the Netherlands (Dutch Declaration of Independence from Spain, 1581), Texas (Texas Declaration of Independence for the Republic of Texas from Mexico, 1836), and New Zealand (Declaration of the Independence of New Zealand, 1835, a declaration of independence of the Maori tribes).
Recent self-declared states also include Chechnya, Somaliland, and Somaliland's neighbor, Puntland.
The Canadian province of Quebec had occasionally threatened to issue a UDI. The Supreme Court of Canada has ruled that a UDI by Quebec would have no legal effect.
In many cases, independence is achieved without a declaration of independence but instead has occurred by bilateral agreement. An example of this were the components of the British Empire, most parts of which achieved independence through negotiation with the United Kingdom.
One notable non-declaration of independence has been Taiwan, which is administered by the Republic of China. A formal declaration that Taiwan is independent of China has been one of conditions under which the People's Republic of China would use force against Taiwan. The political status of Taiwan remains controversial, and the position of most supporters of Taiwan independence has been since the Taiwan has never been a part of the PRC, and the governing institutions (of the ROC) function as an independent and sovereign state, there is no need to formally declare Taiwan to be independent. Supporters of Chinese reunification on Taiwan also see no point in a declaration of independence in that they argue that Taiwan is and should be part of a greater entity cultural entity of China, and a new Republic of Taiwan would only bring about a name change in exchange for a communist invasion attempt Taiwan could little afford.