 But if sovereignty is a matter of authority, it is not a matter of mere authority, but of supreme authority. Supremacy is what makes the constitution of the United States superior to the government of Pennsylvania, or any holder of sovereignty different from a police chief or corporate executive. The holder of sovereignty is superior to all authorities under its purview. Supremacy, too, is endemic to modernity. During the Middle Ages, manifold authorities held some sort of legal warrant for their authority, whether feudal, canonical, or otherwise, but very rarely did such warrant confer supremacy.