Police power is the power of a state to make laws and to use physical violence in order to coerce its subjects into obeying those laws. Thus, it is the most expansive power exercised by a government. States are widely regarded by lawyers and jurists as having an "inherent" right to police power, meaning that it doesn't have to be explicitly written into any basic law or constitutional or other foundational document.

Historically, European monarchs considered police power to be bestowed on them by the Judeo-Christian God. This was known as the Divine Right of Kings. In modern republican governments, the government's police power derives from the sovereignty of the people.

Police power in the United States

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Under the 10th Amendment to the United States Constitution, the powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively. These powers, reserved to the states by the Constitution, include all powers the states retained prior to 1789 (U.S. Term Limits v. Thornton). The framers of the U.S. Constitution believed that the states were empowered, like the British Parliament, with all authority to act on behalf of the welfare of their people.

Because the Congress has limited powers granted in the Constitution, the Federal government does not have a general police power, as the states do. The exceptions are laws regarding Federal property and the military. On the other hand, Congress does have broad quasi-police authority from its power to regulate interstate commerce and raise and spend revenue.

The most common use of police power over real property is for the adoption and enforcement of zoning regulations, building codes, environmental protection regulations, etc. by provincial, local, or regional governments.

Other uses of the police power include public health regulations, vice laws, traffic laws, and family law. However, it is impossible to give a complete list of the uses of police power because a State can write any command or prohibition as a law and make people obey it, as long as such laws do not contradict the State or U.S. Constitution in the opinion of the State or Federal Supreme Court.

See also

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• Law and order (politics)