The term police state describes a state in which the government exercises rigid and repressive controls over the social, economic and political life of the population. A police state typically exhibits elements of totalitarianism and social control, and there is usually little or no distinction between the law and the exercise of political power by the executive.
The inhabitants of a police state experience restrictions on their mobility, and on their freedom to express or communicate political or other views, which are subject to police monitoring or enforcement. Political control may be exerted by means of a secret police force which operates outside the boundaries normally imposed by a constitutional state.
In a free society:
1-Police agencies respond only to evidence of planned and actual criminal activity.
2-Police officers keep the peace; they do not investigate citizens and activities unless there is some reason to investigate.
3-Police do not investigate citizens' attitudes toward the central government, only their action.
4-Citizen dissent is lawful and police agencies do not investigate citizens' attitudes toward the criminal justice apparatus.
We know that the beginning stages of a police state exist in the United States when:
1-A leader is brought into power through illegal means
2-A national catastrophe is used as the pretext to begin a war and institute extraordinary restrictions on constitutional liberties
3-Citizen dissent is held to be treasonous
4-The constitutional separation of powers is abrogated by a power-mad executive branch which controls or intimidates the other two branches of government