Nobody denies that the National Government has unlimited power over foreign commerce—"no sort of trade can be carried on between this country and any other, to which this power does not extend." The same is true of commerce among the States. The power of the National Government over trade with foreign nations, and "among" the several States, is conferred in the same sentence of the Constitution, and "must carry the same meaning throughout the sentence.... The word 'among' means intermingled with." So "commerce among the states cannot stop at the external boundary line of each state, but may be introduced into the interior." This does not, of course, include the "completely interior traffic of a state."[1210]
Everybody knows that foreign commerce is that of the whole Nation and not of its parts. "Every district has a right to participate in it. The deep streams which penetrate our country in every direction, pass through the interior of almost every state in the Union." The power to regulate this commerce "must be exercised whenever the subject exists. If it exists within a state, if a foreign voyage may commence or terminate within a state, then the power of Congress may be exercised within a state."[1211]
If possible, "this principle ... is still more clear, when applied to commerce 'among the several states.' They either join each other, in which case they are separated by a mathematical line, or they are remote from each other, in which case other states lie between them.... Can a trading expedition between two adjoining states commence and terminate outside of each?" The very idea is absurd. And must not commerce between States "remote" from one another, pass through States lying between them? The power to regulate this commerce is in the National Government.[1212]
What is this power to "regulate commerce"? It is the power "to prescribe the rule by which commerce is to be governed. This power ... is complete in itself, may be exercised to its utmost extent, and acknowledges no limitations, other than are prescribed in the constitution;" and these do not affect the present case. Power over interstate commerce "is vested in Congress as absolutely as it would be in a single government" under a Constitution like ours. There is no danger that Congress will abuse this power, because "the wisdom and the discretion of Congress, their identity with the people, and the influence which their constituents possess at election, are, in this, as in many other instances, as that, for example, of declaring war, the sole restraints on which they [the people] have relied, to secure them from its abuse. They are restraints on which the people must often rely solely, in all representative governments." The upshot of the whole dispute is, declares Marshall, that Congress has power over navigation "within the limits of every state ... so far as that navigation may be, in any manner, connected" with foreign or interstate trade.[1213]
Marshall tries to answer the assertion that the power to regulate commerce is concurrent in Congress and the State Legislatures; but, in doing so, he is diffuse, prolix, and indirect. There is, he insists, no analogy between the taxing power of Congress and its power to regulate commerce; the former "does not interfere with the power of the states to tax for the support of their own governments." In levying such taxes, the States "are not doing what Congress is empowered to do." But when a State regulates foreign or interstate commerce, "it is exercising the very power ... and doing the very thing which Congress is authorized to do." However, says Marshall evasively, in the case before the court the question whether Congress has exclusive power over commerce, or whether the States can exercise it until Congress acts, may be dismissed, since Congress has legislated on the subject. So the only practical question is: "Can a state regulate commerce with foreign nations and among the states while Congress is regulating it?"[1214]
The argument is not sound that, since the States are expressly forbidden to levy duties on tonnage, exports, and imports which they might otherwise have levied, they may exercise other commercial regulations, not in like manner expressly prohibited. For the taxation of exports, imports, and tonnage is a part of the general taxing power and is not connected with the power to regulate commerce. It is true that duties on tonnage often are laid "with a view to the regulation of commerce; but they may be also imposed with a view to revenue," and, therefore, the States are prohibited from laying such taxes. There is a vast difference between taxation for the regulation of commerce and taxation for raising revenue. "Those illustrious statesmen and patriots" who launched the Revolution and framed the Constitution understood and acted upon this distinction: "The right to regulate commerce, even by the imposition of duties, was not controverted; but the right to impose a duty for the purpose of revenue, produced a war as important, perhaps, in its consequences to the human race, as any the world has ever witnessed."[1215]
In the same way, State inspection laws, while influencing commerce, do not flow from a power to regulate commerce. The purpose of inspection laws is "to improve the quality of the articles produced by the labor of the country.... They act upon the subject before it becomes an article" of foreign or interstate commerce. Such laws "form a portion of that immense mass of legislation which embraces everything within the territory of a state," and "which can be most advantageously exercised by the states themselves." Of this description are "inspection laws, quarantine laws, health laws ... as well as laws for regulating the internal commerce of a state, and those which respect turnpike-roads, ferries, etc."[1216]
Legislation upon all these subjects is a matter of State concern—Congress can act upon them only "for national purposes ... where the power is expressly given for a special purpose, or is clearly incidental to some power which is expressly given." Obviously, however, the National Government "in the exercise of its express powers, that, for example, of regulating [foreign and interstate] commerce ... may use means that may also be employed by a state, ... that, for example, of regulating commerce within the state." The National coasting laws, though operating upon ports within the same State, imply "no claim of a direct power to regulate the purely internal commerce of a state, or to act directly on its system of police." State laws on these subjects, although of the "same character" as those of Congress, do not flow from the same source whence the National laws flow, "but from some other, which remains with the state, and may be executed by the same means." Although identical measures may proceed from different powers, "this does not prove that the powers themselves are identical."[1217]
It is inevitable in a "complex system" of government like ours that "contests respecting power must arise" between State and Nation. But this "does not prove that one is exercising, or has a right to exercise, the powers of the other."[1218] It cannot be inferred from National statutes requiring National officials to "conform to, and assist in the execution of the quarantine and health laws of a state ... that a state may rightfully regulate commerce"; such laws flow from "the acknowledged power of a state, to provide for the health of its citizens." Nevertheless, "Congress may control the state [quarantine and health] laws, so far as it may be necessary to control them, for the regulation of commerce."[1219]
Marshall analyzes, at excessive length, National and State laws on the importation of slaves, on pilots, on lighthouses,[1220] to show that such legislation does not justify the inference that "the states possess, concurrently" with Congress, "the power to regulate commerce with foreign nations and among the states."