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
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.