Supreme authority in a state. In any state sovereignty is vested in the institution, person, or body having the ultimate authority to impose law on everyone else in the state and the power to alter any pre-existing law. How and by whom the authority is exercised varies according to the political nature of the state. In many countries the executive, legislative, and judicial powers of sovereignty are exercised by different bodies. One of these bodies may in fact retain sovereignty by having ultimate control over the others. But in some countries, such as the USA, the powers are carefully balanced by a constitution. In the UK sovereignty is vested in Parliament (see sovereignty of Parliament).
In international law, it is an essential aspect of sovereignty that all states should have supreme control over their internal affairs, subject to the recognized limitations imposed by international law. These limitations include, in particular, the international law of human rights and the rules forbidding the use of force. However, no state or international organization may intervene in matters that fall within the domestic jurisdiction of another state. The concept of state sovereignty was outlined, among other things, in a declaration on Principles of International Law (Resolution 2625), proclaimed by the General Assembly of the United Nations in 1970.