police power, in law, right of a government to make laws necessary for the health, morals, and welfare of the populace. The term has greatest currency in the United States, where it has been defined by the Supreme Court as the power of the states to enact laws of that type even where, under ordinary circumstances, Constitutional law or federal statute would override them. The doctrine was first stated by Chief Justice John Marshall, who ruled that the power of Congress over interstate commerce (Article 1, Section 8) could not prevent the states from controlling goods shipped from another state after they had been broken out of the original package. The concept of police power became very important after the passage (1868) of the Fourteenth Amendment; on the one hand, the states had to be restrained from taking liberty or property without due process of law; on the other hand, the states could not be made helpless in dealing with grave problems of an economic and social nature. Gradually the court moved away from its initial strict interpretation of the Fourteenth Amendment, during which time it had struck down economic regulations such as minimum wages and maximum hours as a violation of the amendment's due-process clause. Since the late 1930s, however, the court has upheld almost all state economic regulation as falling within the police power.