Diplomatic recognition in international law is a unilateral political act with domestic and international legal consequences, whereby a state acknowledges an act or status of another state or government in control of a state (may be also an unrecognised state). Recognition can be accorded either de facto or de jure, usually by a statement of the recognizing government.
Recognition of states and governments
Diplomatic recognition must be distinguished from formal recognition of states or their governments. The fact that states do not maintain bilateral diplomatic relations does not mean that they do not recognize or treat one another as states. A state is not required to accord formal bilateral recognition to any other state, and some have a general policy of not doing so, considering that a vote for its membership of an international organisation restricted to states, such as the United Nations, is proof of recognition. Some consider that a state has a responsibility not to recognize as a state any entity that has attained the qualifications for statehood by a violation of basic principles of the UN Charter: the UN Security Council has in several instances (for example, Rhodesia and the Turkish Republic of North Cyprus) issued Chapter VII resolutions (binding in international law) which deny their statehood and should preclude recognition (though in the 2010 Kosovo decision, the United Nations Permanent Court of Justice decided that "there is nothing in international law that prohibits the declaration of independence" and UNSC's 1983 resolution that states "declaration of independence of TRNC is illegal" became legally invalid since UN PCJ supersides UNSC in international law. States can exercise their recognition powers either explicitly or implicitly. The recognition of a government implies recognition of the state it governs, but even countries which have a policy of formally recognising states may not have a policy of doing the same regarding governments.
De facto recognition of states, rather than de jure, is rare. De jure recognition is stronger, while de facto recognition is more tentative and recognizes only that a government exercises control over a territory. An example of the difference is when the United Kingdom recognized the Soviet Union de facto in 1921, but de jure only in 1924. Another example is the state of Israel in 1948, whose government was immediately recognized de facto by the United States and three days later by Soviet de jure recognition. Also, the Republic of China, commonly known as "Taiwan", is generally recognized as de facto independent and sovereign, but is not universally recognized as de jure independent due to the complex political status of Taiwan related to the United Nation's de-recognization of it in favor of the People's Republic of China in 1971.
Renewing recognition of a government is not necessary when it changes in a normal, constitutional way (such as an election or referendum), but is necessary in the case of a coup d'etat or revolution. Recognition of a new government by other states can be important for its long term survival. For instance, the Taliban government of the Islamic State of Afghanistan, which lasted from 1996 to 2001, was recognized by only Pakistan, the United Arab Emirates, and Saudi Arabia, while far more had recognized the government of ousted President Burhanuddin Rabbani. The disputed territory of Jammu and Kashmir of the Republic of India is not recognized by either Pakistan or the People's Republic of China.
Recognition can be implied by other acts, like the visit of the head of state, or the signing of a bilateral treaty. If implicit recognition is possible, a state may feel the need to explicitly proclaim that its acts do not constitute diplomatic recognition, like when the United States commenced its dialogue with the Palestine Liberation Organization in 1988.
The doctrine of non-recognition of illegal or immoral situations, like territorial gains achieved by force, is called the Stimson Doctrine, and has become more important since the Second World War, especially in the United Nations where it is a method of ensuring compliance with international law - for instance, in the case of Rhodesia in 1965. Withdrawal of recognition of a government is a more severe act of disapproval than the breaking of diplomatic relations.
Recognition of governments
Besides recognizing other states, states also can recognize the governments of states. This can be problematic particularly when a new government comes to power by illegal means, such as a coup d'etat, or when an existing government stays in power by fixing an election. States once formally recognized both the government of a state and the state itself, but many no longer follow that practice, even though, if diplomatic relations are to be maintained, it is necessary that there be a government with which to engage in diplomatic relations. Countries such as the United States answer queries over the recognition of governments with the statement: "The question of recognition does not arise: we are conducting our relations with the new government."
Several of the world's geo-political entities lack general international recognition, but wish to be recognized as sovereign states. The degree of de facto control these entities exert over the territories they claim varies.
Most are subnational regions with an ethnic or national identity of their own that have separated from the original parent state. Such states are commonly referred to as "break-away" states. Some of these entities are in effect internally self-governing protectorates that enjoy military protection and informal diplomatic representation abroad through another state to prevent forced reincorporation into their original states.
Note that the word "control" in this list refers to control over the area occupied, not occupation of the area claimed. Unrecognized countries may have either full control over their occupied territory, or only partial control (such as Western Sahara). In the former, the de jure governments have little or no influence in the areas they claim to rule, whereas in the latter they have varying degrees of control, and may provide essential services to people living in the areas.
Other types of recognition
Other elements that may be recognized, include occupation or annexation of territory, or belligerent rights of a party in a conflict. Recognition of the latter does not imply recognition of a state. Examples of recognition of belligerent status include:
- The United Kingdom recognized the Confederate States of America as a belligerent in the first month of the American Civil War.
- Bolivia, Colombia, Ecuador, Peru, Soviet Union and Venezuela recognized the Sandinista National Liberation Front as a belligerent in Nicaragua's civil war in June, 1979.
- France and Mexico recognized the FMLN as a belligerent in the civil war in El Salvador on August 28, 1981.
- See Stefan Talmon, Recognition of Governments in International Law: With Particular Reference to Governments in Exile (Oxford: Clarendon Press, 1998) pages 1-4
- See for example "The Restatement (Third) Foreign Relations Law of the United States, American Law Institute Publishers, 1990, ISBN 0-314-30138-0, §202 Recognition or Acceptance of States; and §203 Recognition or Acceptance of Governments; and §204 Recognition and Maintaining Diplomatic Relations
- See for example, the oral arguments in the International Court of Justice case on Kosovo's declaration of independence. CR 2009/32, page 39 
- Since the 1970s the United States Department of State has moved away from the practice of recognizing governments. See:  Digest of U.S. Practice in International Law 19-21.
-  Digest of U.S. Practice in International Law at 13;  Digest of U.S. Practice in International Law at 34.
- Tozun Bahcheli, Barry Bartmann, and Henry Srebrnik; De Facto States: The Quest for Sovereignty , Routledge, (2004) online edition
- Edgars Dunsdorfs (1975). The Baltic Dilemma, The case of the de jure recognition of incorporation of the Baltic States into the Soviet Unions by Australia. Robert Speller & Sons, New York. ISBN 0-8315-0148-0.
- Gerhard von Glahn (1992). Law Among Nations: An Introduction to Public International Law. Macmillan. ISBN 0-02-423175-4.
- Malcolm N. Shaw (2003). International Law. Cambridge University Press. ISBN 0-521-53183-7.
- Stefan Talmon; Recognition of Governments in International Law: With Particular Reference to Governments in Exile Clarendon Press, (1998) online edition
- Gregory Weeks; "Almost Jeffersonian: U.S. Recognition Policy toward Latin America," Presidential Studies Quarterly, Vol. 31, 2001 online edition