In the United States, the dichotomy between state and federal competence is expressed in the Tenth Amendment to the Constitution: "The powers that the Constitution does not delegate to the United States, and which does not prohibit States from exercising, are reserved to each State, or to the people. "That is, we clearly have state power as the rule, and may even adopt opposing positions among states. However, interpretations other than that given to the federal common law are not allowed.
In this way, there is a federative balance between the national matters, legislated by the federation congressmen, and among the state matters, legislated by the state congresses. In this way, the states maintain the broad decision-making power in matters of their competence and regional interest.