Answer:
National security.
Step-by-step explanation:
The concept of "reason of state" asserts that the main purpose of a state is to secure its own continued existence, by whatever means necessary. And according to German sociologist Max Weber, the most fundamental and defining element of any state is its monopoly on the legitimate use of violence. So following these two ideas, a state that can't physically guarantee its own safety and continued existence is not viable. The only way to guarantee its continuity is to hold the physical means to defend the state from internal and external threats. This is called national security. A government that had its means of protecting national security taken away from it, would collapse very quickly as a result of a coup d'etat, civil war, revolution, or foreign invasion.