The inherent power of a government to regulate its police affairs.
"The term police power is not definitely fixed in meaning. In the earlier cases in the United States it was used as including the whole power of internal government, or the powers of government inherent in every sovereignty to the extent of its dominions (11 Peters (U. S.) 102). The later cases have excepted from its domain the development and administration of private law. Modern political science defines the power as a branch of internal administration in the exercise of which the executive should move within the lines of general principles prescribed by the constitution or the legislature, and in the exercise of which the most local governmental organizations should participate as far as possible (Burgess). Under this limitation the police power, as affecting persons, is the power of the state to protect the public against the abuse of individual liberty, that is, to restrain the individual in the exercise of his rights when such exercise becomes a danger to the community. The tendency of judicial and popular usage is towards this narrower definition.
[Webster 1913 Suppl.