Jones & Laughlin Steel, Darby, and Wickard ushered in an era of Commerce Clause jurisprudence that greatly expanded the previously defined authority of Congress under that Clause. In part, this was a recognition of the great changes that had occurred in the way business was carried on in this country. Enterprises that had once been local or at most regional in nature had become national in scope. But the doctrinal change also reflected a view that earlier Commerce Clause cases artificially had constrained the authority of Congress to regulate interstate commerce.
But even these modern-era precedents which have expanded congressional power under the Commerce Clause confirm that this power is subject to outer limits. In Jones & Laughlin Steel, the Court warned that the scope of the interstate commerce power “must be considered in the light of our dual system of government and may not be extended so as to embrace effects upon interstate commerce so indirect and remote that to embrace them, in view of our complex society, would effectually obliterate the distinction between what is national and what is local and create a completely centralized government.” See Wickard, supra, at 125 (Congress may regulate activity that “exerts a substantial economic effect on interstate commerce”). Since that time, the Court has heeded that warning and undertaken to decide whether a rational basis existed for concluding that a regulated activity sufficiently affected interstate commerce. See, e.g., Katzenbach v. McClung, 379 U.S. 294, 299-301 (1964); Heart of Atlanta Motel, Inc. v. United States, 379 U.S. 241, 252-253 (1964). . . .