We start with first principles. The Constitution creates a Federal Government of enumerated powers. As James Madison wrote, “[t]he powers delegated by the proposed Constitution to the federal government are few and defined. Those which are to remain in the State governments are numerous and indefinite.” The Federalist No. 45, pp. 292-293. This constitutionally mandated division of authority “was adopted by the Framers to ensure protection of our fundamental liberties.” “Just as the separation and independence of the coordinate branches of the Federal Government serves to prevent the accumulation of excessive power in any one branch, a healthy balance of power between the States and the Federal Government will reduce the risk of tyranny and abuse from either front.”
The Constitution delegates to Congress the power “[t]o regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes.” The Court, through Chief Justice Marshall, first defined the nature of Congress’ commerce power in Gibbons v. Ogden, 9 Wheat. 1, 189-190, 6 L.Ed. 23 (1824):
“Commerce, undoubtedly, is traffic, but it is something more: it is intercourse. It describes the commercial intercourse between nations, and parts of nations, in all its branches, and is regulated by prescribing rules for carrying on that intercourse.”
The commerce power “is the power to regulate; that is, to prescribe the rule by which commerce is to be governed. This power, like all others vested in Congress, is complete in itself, may be exercised to its utmost extent, and acknowledges no limitations, other than are prescribed in the constitution.” The Gibbons Court, however, acknowledged that limitations on the commerce power are inherent in the very language of the Commerce Clause.
“It is not intended to say that these words comprehend that commerce, which is completely internal, which is carried on between man and man in a State, or between different parts of the same State, and which does not extend to or affect other States. Such a power would be inconvenient, and is certainly unnecessary.
“Comprehensive as the word ‘among’ is, it may very properly be restricted to that commerce which concerns more States than one. . . . The enumeration presupposes something not enumerated; and that something, if we regard the language or the subject of the sentence, must be the exclusively internal commerce of a State.”