A System of National Laws
National laws were created by the national sovereign (king or parliament) and the nation-state was bound only by the laws that it created or international treaties that it agreed to accept.
National Sovereignty
In earlier times, a strong central ruler would make the laws and enforce them. Each leader or ruler became an “emperor” in his or her nation-state and answerable to no one else.
Popular sovereignty then evolved, which meant that leaders were more answerable to their people and interpreting the wishes of their people. However, it was still the ruler making the decisions and not being answerable to anyone else outside the nation-state.