A “nation state” is defined as a political entity characterized by a defined territory, a permanent population, a sovereign government, and the capacity to establish relations with other states. The nation state serves as the primary unit of political organization and sovereignty in the international system. The national identity of a nation state provides the framework for the expression and preservation of cultural, linguistic, and historical identity. In 1648, the Treaties of Westphalia, which ended the Thirty Years’ War, laid the foundations of the modern nation-state system and emphasized the principle of sovereignty. In the following years, the concept of the nation state gained importance, especially with the French Revolution (1789) and the Napoleonic Wars (1803–1815). In summary, a nation state is a political entity with a defined territory, a permanent population, and a sovereign government, representing the combination of national identity and political authority.

• Krastev, I. (2007). The crisis of the nation-state: A critical analysis. In Contemporary security studies (pp. 42-58). Routledge.