In times of war, belligerent countries can be contrasted with neutral countries and non-belligerents. However, the application of the laws of war to neutral countries and the responsibilities of belligerents are not affected by any distinction between neutral countries, neutral powers or non-belligerents. A non-belligerent may nevertheless risk being considered a belligerent if it aids or supports a belligerent in a way proscribed by neutral countries.
An interesting use of the term arose during the American Civil War, when the Confederate States of America, though not recognized as a sovereign state, was recognized as a belligerent power, and thus Confederate warships were given the same rights as United States warships in foreign ports.
Belligerency is a term used in international law to indicate the status of two or more entities, generally sovereign states, being engaged in a war. Wars are often fought with one or both parties to a conflict invoking the right to self defence under Article 51 of the United Nations Charter, (As did the United Kingdom in 1982 before the start of the Falklands War) or under the auspices of a United Nations Security Council resolution (such as the United Nations Security Council Resolution 678 which gave legal authorization for the Gulf War).
A state of belligerency may also exist between one or more sovereign states on one side, and rebel forces, if such rebel forces are recognised as belligerents. If there is a rebellion against an constituted authority (for example an authority recognised as such by the United Nations) and those taking part in the rebellion are not recognised as belligerents then the rebellion is an insurgency.
Since the beginning of the crystallization of various concepts of international law, also called the law of nations, the concept of belligerency and the rights and duties of belligerent nations have continued to evolve and become codified. In the modern context, a number of regulations relating to belligerency were annexed to the Hague Convention of 29th July 1899, pertaining to the laws and customs of war. The Convention contained a specific section named Belligerents which was divided into three chapters, dealing respectively with the following:
Once the status of belligerency is established between two or more states, their relations are determined and governed by the laws of war.