In international law, sovereignty means that a government possesses full control over affairs within a territorial or geographical area or limit. Determining whether a specific entity is sovereign is not an exact science, but often a matter of diplomatic dispute. There is usually an expectation that both "de jure" and "de facto" sovereignty rest in the same organisation at the place and time of concern. Foreign governments use varied criteria and political considerations when deciding whether or not to recognise the sovereignty of a state over a territory. Membership in the United Nations requires that "he admission of any such state to membership in the United Nations will be effected by a decision of the General Assembly upon the recommendation of the Security Council."