Sovereignty is the exclusive right to have complete control over an area of governance, people, or oneself. A sovereign is the supreme lawmaking authority, subject to no other. Jean-Jacques Rousseau, in Book III, Chapter III of his 1763 treatise Of the Social Contract, argued that "the growth of the State giving the trustees of public authority more and means to abuse their power, the more the Government has to have force to contain the people, the more force the Sovereign should have in turn in order to contain the Government," with the understanding that the Sovereign is "a collective being" (Book II, Chapter I) resulting from "the general will" of the people, and that "what any man, whoever he may be, orders on his own, is not a law" (Book II, Chapter VI) – and furthermore predicated on the assumption that the people have an unbiased means by which to ascertain the general will. Thus the legal maxim, "there is no law without a sovereign."

In this model, national sovereignty is of an eternal origin, such as nature, or a god, legitimating the divine right of kings in absolute monarchies or a theocracy.

A more formal distinction is whether the law is held to be sovereign, which constitutes a true state of law: the letter of the law (if constitutionally correct) is applicable and enforceable, even when against the political will of the nation, as long as not formally changed following the constitutional procedure. Strictly speaking, any deviation from this principle constitutes a revolution or a coup d'état, regardless of the intentions.

In constitutional and international law, the concept also pertains to a government possessing full control over its own affairs within a territorial or geographical area or limit, and in certain context to various organs possessing legal jurisdiction in their own chief, rather than by mandate or under supervision. Determining whether a specific entity is sovereign is not an exact science, but often a matter of diplomatic dispute.