In the U.S. constitutional system, each state possesses a traditional authority to regulate in the name of public health, safety, and welfare. Known as the police powers, this authority has deep roots in Anglo-American law. In his landmark
Commentaries on the Laws of England (1765), the British legal theorist William Blackstone defined the police powers as "the due regulation and domestic order of the kingdom, whereby the inhabitants of a State, like members of a well-governed family, are bound to conform their general behavior to the rules of propriety, good neighborhood, and good manners, and to be decent, industrious, and inoffensive in their respective stations."
Citing Blackstone, the American legal theorist Thomas Cooley, in his influential
Treatise on the Constitutional Limitations Which Rest upon the Legislative Power of the States of the American Union (1871), said the police powers of a state "embraces its system of internal regulation, by which it is sought not only to preserve the public order and to prevent offenses against the State, but also to establish for the intercourse of citizen with citizen those rules of good manners and good neighborhood which are calculated to prevent a conflict of rights, and to insure to each the uninterrupted enjoyment of his own, so far as is reasonably consistent with a like enjoyment of rights by others."
https://reason.com/2020/03/18/police-powers-during-a-pandemic-constitutional-but-not-unlimited/