Whatsoever is of domestic concernment, unconnected with the other members of the Union… — John Quincy Adams

Whatsoever is of domestic concernment, unconnected with the other members of the Union or with foreign lands, belongs exclusively to the administration of the State governments. Whatsoever directly involves the rights and interests of the federative fraternity or of foreign powers is of the resort of this General Government. The duties of both are obvious in the general principle, though sometimes perplexed with difficulties in the detail.