Westphalian sovereignty is the concept of nation-state sovereignty based on territoriality and the absence of a role for external agents in domestic structures. It is an international system of states, multinational corporations, and organizations that began with the Peace of Westphalia in 1648.
Sovereignty is a term that is frequently misused. Up until the 19th century, the radicalised concept of a "standard of civilization" was routinely deployed to determine that certain people in the world were "uncivilized", and lacking organised societies. That position was reflected and constituted in the notion that their "sovereignty" was either completely lacking or at least of an inferior character when compared to that of the "civilized" people." Lassa Oppenheim said, "There exists perhaps no conception the meaning of which is more controversial than that of sovereignty. It is an indisputable fact that this conception, from the moment when it was introduced into political science until the present day, has never had a meaning which was universally agreed upon." In the opinion of H. V. Evatt of the High Court of Australia, "sovereignty is neither a question of fact, nor a question of law, but a question that does not arise at all."
Sovereignty has taken on a different meaning with the development of the principle of self-determination and the prohibition against the threat or use of force as jus cogens norms of modern international law. The United Nations Charter, the
Draft Declaration on Rights and Duties of States, and the charters of regional international organizations express the view that all states are juridically equal and enjoy the same rights and duties based upon the mere fact of their existence as persons under international law. The right of nations to determine their own political status and exercise permanent sovereignty within the limits of their territorial jurisdictions is widely recognized.
In political science, sovereignty is usually defined as the most essential attribute of the state in the form of its complete self-sufficiency in the frames of a certain territory, that is its supremacy in the domestic policy and independence in the foreign one.
Named after the 1648 Treaty of Westphalia, the Westphalian System of state sovereignty, which according to Bryan Turner is "made a more or less clear separation between religion and state, and recognized the right of princes 'to confessionalize' the state, that is, to determine the religious affiliation of their kingdoms on the pragmatic principle of cuius regio eius religio [whose realm, his religion]."
Before 1900 sovereign states enjoyed an absolute immunity from the judicial process, derived from the concepts of sovereignty and the Westphalian
equality of states. First articulated by Jean Bodin, the powers of the state are considered to be suprema potestas within territorial boundaries. Based on this, the jurisprudence has developed along the lines of affording immunity from prosecution to foreign states in domestic courts. In The Schooner Exchange v. M'Faddon, Chief Justice John Marshall of the United States Supreme Court wrote that the "perfect equality and absolute independence of sovereigns" has created a class of cases where "every sovereign is understood to waive the exercise of a part of that complete exclusive territorial jurisdiction, which has been stated to be the attribute of every nation".
Absolute sovereign immunity is no longer as widely accepted as it has been in the past, and some countries including the United States, Canada, Singapore, Australia, Pakistan and South Africa have introduced
restrictive immunity by statute, which explicitly limits jurisdictional immunity to public acts, but not private or commercial ones, though there is no precise definition by which public acts can easily be distinguished from private ones.