The commerce clause as an instrument of federalism facilitates a system of government that places a national government over fifty sovereign states. Federalism requires a balancing of the interest in a unified national approach to government with the competing interest in state sovereignty. As Justice Brennan explained:
"Our Constitution is an instrument of federalism. The Constitution furnishes the structure for the operation of the States with respect to the National Government and with respect to each other.. ..Because there are 49 States and much of the Nation's commercial activity is carried on by enterprises having contacts with more States than one, a common and continuing problem of constitutional interpretation has been that of adjusting the demands of individual States to regulate and tax these enterprises in light of the multi-state nature of our federation."
The commerce clause provides: "The Congress shall have Power ... To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes."' The commerce clause has been interpreted not only as conferring power on the national government to regulate commerce, but also as limiting the states' power to interfere with commerce. This restriction on state power often is referred to as the "negative implication of the commerce clause" or as the "dormant commerce clause" principle. Under the authority of the commerce clause, the United States Supreme Court has struck down as unconstitutional a variety of state regulatory and taxation measures as unduly burdening commerce.
Philip M. Tatarowicz and Rebecca F. Mims-Velarde,
Symposium on State and Local Taxation,
39 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vlr/vol39/iss4/1