The concept of national sovereignty was established by the

philosopher John Locke

The theories of the English philosopher John Locke (1632–1704) and the French philosopher Jean-Jacques Rousseau (1712–78)—that the state is based upon a formal or informal compact of its citizens, a social contract through which they entrust such powers to a government as may be necessary for common protection

Explanation:

answer; having the power of reprieve means being able to release people from punishment;