The term 'political unity of states (PERT. TO)' can be summarized as the concept of federalism, which is a system of government in which power is divided between a central authority and constituent political units. Federalism is a key component of many modern democracies, including the United States, where it is enshrined in the Constitution. It allows for the sharing of power between the national government and the individual states, creating a balance of power that ensures the rights of citizens are respected and protected.