The formal overruling of Hammer v. Dagenhart, however, did not occur until 1941 when, in sustaining the Fair Labor Standards Act, a unanimous Court, speaking by Justice Stone, said: "Hammer v. Dagenhart has not been followed. The distinction on which the decision was rested that Congressional power to prohibit interstate commerce is limited to articles which in themselves have some harmful or deleterious property—a distinction which was novel when made and unsupported by any provision of the Constitution—has long since been abandoned. * * * The thesis of the opinion that the motive of the prohibition or its effect to control in some measure the use or production within the States of the article thus excluded from the commerce can operate to deprive the regulation of its constitutional authority has long since ceased to have force. * * * And finally we have declared 'The authority of the Federal Government over interstate commerce does not differ in extent or character from that retained by the States over intrastate commerce.' United States v. Rock Royal Co-operative, 307 U.S. 533, 569. The conclusion is inescapable that Hammer v. Dagenhart, was a departure from the principles which have prevailed in the interpretation of the Commerce Clause both before and since the decision and that such vitality, as a precedent, as it then had has long since been exhausted. It should be and now is overruled."[519] And commenting in a recent case on the Fair Labor Standards Act, Justice Burton, speaking for the Court said: "The primary purpose of the act is not so much to regulate interstate commerce as such, as it is, through the exercise of legislative power, to prohibit the shipment of goods in interstate commerce if they are produced under substandard labor conditions."[520]
CONGRESS AND THE FEDERAL SYSTEM
In view of these developments the following dictum by Justice Frankfurter, was no doubt, intended to be reassuring as to the future of the Federal System: "The interpenetrations of modern society have not wiped out State lines. It is not for us [the Court] to make inroads upon our federal system either by indifference to its maintenance or excessive regard for the unifying forces of modern technology. Scholastic reasoning may prove that no activity is isolated within the boundaries of a single State, but that cannot justify absorption of legislative power by the United States over every activity."[521] While this may be conceded, the unmistakable lesson of recent cases is that the preservation of our Federal System depends today mainly upon Congress.
The Commerce Clause as a Restraint on State Powers
DOCTRINAL BACKGROUND
The grant of power to Congress over commerce, unlike that of power to levy customs duties, the power to raise armies, and some others, is unaccompanied by correlative restrictions on State power. This circumstance does not, however, of itself signify that the States were expected still to participate in the power thus granted Congress, subject only to the operation of the supremacy clause. As Hamilton points out in The Federalist, while some of the powers which are vested in the National Government admit of their "concurrent" exercise by the States, others are of their very nature "exclusive," and hence render the notion of a like power in the States "contradictory and repugnant."[522] As an example of the latter kind of power Hamilton mentioned the power of Congress to pass a uniform naturalization law. Was the same principle expected to apply to the power over foreign and interstate commerce?
Unquestionably one of the great advantages anticipated from the grant to Congress of power over commerce was that State interferences with trade, which had become a source of sharp discontent under the Articles of Confederation, would be thereby brought to an end. As Webster stated in his argument for appellant in Gibbons v. Ogden: "The prevailing motive was to regulate commerce; to rescue it from the embarrassing and destructive consequences, resulting from the legislation of so many different States, and to place it under the protection of a uniform law." In other words, the constitutional grant was itself a regulation of commerce in the interest of uniformity. Justice Johnson's testimony in his concurring opinion in the same case is to like effect: "There was not a State in the Union, in which there did not, at that time, exist a variety of commercial regulations; * * * By common consent, those laws dropped lifeless from their statute books, for want of sustaining power that had been relinquished to Congress";[523] and Madison's assertion, late in life, that power had been granted Congress over interstate commerce mainly as "a negative and preventive provision against injustice among the States,"[524] carries a like implication.
That, however, the commerce clause, unimplemented by Congressional legislation, took from the States any and all power over foreign and interstate commerce was by no means universally conceded; and Ogden's attorneys directly challenged the idea. Moreover, as was pointed out on both sides in Gibbons v. Ogden, legislation by Congress regulative of any particular phase of commerce would still leave many other phases unregulated and consequently raise the question whether the States were entitled to fill the remaining gaps, if not by virtue of a "concurrent" power over interstate and foreign commerce, then by virtue of "that immense mass of legislation," as Marshall termed it, "which embraces everything within the territory of a State, not surrendered to the general government,"[525]—in a word, the "police power."
The commerce clause does not, therefore, without more ado, settle the question of what power is left to the States to adopt legislation regulating foreign or interstate commerce in greater or less measure. To be sure, in cases of flat conflict between an act or acts of Congress regulative of such commerce and a State legislative act or acts, from whatever State power ensuing, the act of Congress is today recognized, and was recognized by Marshall, as enjoying an unquestionable supremacy.[526] But suppose, first, that Congress has passed no act; or secondly, that its legislation does not clearly cover the ground which certain State legislation before the Court attempts to cover—what rules then apply? Since Gibbons v. Ogden both of these situations have confronted the Court, especially as regards interstate commerce, hundreds of times, and in meeting them the Court has, first and last, coined or given currency to numerous formulas, some of which still guide, even when they do not govern, its judgment.