Totalitarianism is any political system, or ideologies that support such a system, in which a centralized political authority controls every aspects of life, including economics, culture, and religion, and all civil institutions are tightly under the direct authority of the government. Political oppression, show trials and summary executions are generally prevalent in totalitarian states. Civil liberties is little or non-existent in totalitarian societies. The government in a totalitarian society often uses secret police to enforce its power and to terrorize the populace. Sometimes the term "police state" is interchangeale with "totalitarian state". Examples of totalitarian states include Nazi Germany and states under communism.