Opinion of the Court.

as to require exclusive legislation by Congress. Cooley v. Port Wardens, 12 How. 299; Crandall v. State of Nevada, 6 Wall. 42. Surely transportation of passengers or merchandise through a State, or from one State to another, is of this nature. It is of national importance that over that subject there should be but one regulating power, for if one State can directly tax persons or property passing through it, or tax them indirectly by levying a tax upon their transportation, every other may, and thus commercial intercourse between States remote from each other may be destroyed. The produce of Western States may thus be effectually excluded from Eastern markets, for though it might bear the imposition of a single tax, it would be crushed under a load of many. It was to guard against the possibility of such commercial embarrassments, no doubt, that the power of regulating commerce among the States was conferred upon the Federal government."

The distinction between cases in which Congress has exerted its power over commerce, and those in which it has abstained from its exercise, as bearing upon state legislation touching the subject was first plainly pointed out by Mr. Justice Curtis in the case of Cooley v. Port Wardens, 12 How. 299, and applies to commerce with foreign nations as well as to commerce among the States. In that case, speaking of commerce with foreign nations, he said (p. 319): "Now, the power to regulate commerce embraces a vast field, containing not only many, but exceedingly various subjects quite unlike in their nature; some imperatively demanding a single uniform rule operating equally on the commerce of the United States in every port; and some, like the subject now in question, as imperatively demanding that diversity which alone can meet the local necessities of navigation." It was, therefore, held in that case that the laws of the several States concerning pilotage, although in their nature regulations of foreign commerce, were, in the absence of legislation on the same subject by Congress, valid exercises of power. The subject was local and not national, and was likely to be best provided for, not by one system or plan of regulations, but by as many as the legislative discretion of the several States should deem appli

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cable to the local peculiarities of the ports within their limits; and to this it may be added that it was a subject imperatively demanding positive regulation. The absence of legislation on the subject, therefore, by Congress, was evidence of its opinion that the matter might be best regulated by local authority, and proof of its intention that local regulations might be made.

It may be argued, however, that, aside from such regulations as these, which are purely local, the inference to be drawn from the absence of legislation by Congress on the subject excludes state legislation affecting commerce with foreign nations more strongly than that affecting commerce among the States. Laws which concern the exterior relations of the United States with other nations and governments are general in their nature, and should proceed exclusively from the legislative authority of the nation. The organization of our state and Federal system of government is such that the people of the several States can have no relations with foreign powers in respect to commerce or any other subject, except through the government of the United States and its laws and treaties. Henderson v. Mayor of New York, 92 U. S. 259, 273.

The same necessity perhaps does not exist equally in reference to commerce among the States. The power conferred upon Congress to regulate commerce among the States is indeed contained in the same clause of the Constitution which confers upon it power to regulate commerce with foreign nations. The grant is conceived in the same terms, and the two powers are undoubtedly of the same class and character and equally extensive. The actual exercise of its power over either subject is equally and necessarily exclusive of that of the States, and paramount over all the powers of the States; so that state legislation, however legitimate in its origin or object, when it conflicts with the positive legislation of Congress, or its intention reasonably implied from its silence, in respect to the subject of commerce of both kinds, must fail. And yet in respect to commerce among the States, it may be for the reason already assigned, that the same inference is not always to be drawn from the absence of congressional legislation as might be in the case of commerce with foreign

Opinion of the Court.

nations. The question, therefore, may be still considered in each case as it arises, whether the fact that Congress has failed in the particular instance to provide by law a regulation of commerce among the States is conclusive of its intention that the subject shall be free from all positive regulation, or that, until it positively interferes, such commerce may be left to be freely dealt with by the respective States.

We have seen that in the case of the State Freight Tax, 15 Wall. 232, a tax imposed by one State upon freight transported to or from another State was held to be void as a regulation of commerce among the States, on the ground that the transportation of passengers or merchandise through a State, or from one State to another, was in its nature national, so that it should be subjected to one uniform system or plan of regulation under the control of one regulating power. In that case the tax was not imposed for the purpose of regulating interstate commerce, but in order to raise a revenue, and would have been a legitimate exercise of an admitted power of the State if it had not been exerted so as to operate as a regulation of interstate commerce. Any other regulation of interstate commerce, applied as the tax was in that case, would fall equally within the rule of its decision. If the State has not power to tax freight and passengers passing through it, or to or from it, from or into another State, much less would it have the power directly to regulate such transportation, or to forbid it altogether. If in the present case the law of Iowa operated upon all merchandise sought to be brought from another State into its limits, there could be no doubt that it would be a regulation of commerce among the States and repugnant to the Constitution of the United States. In point of fact, however, it applies only to one class of articles of a particular kind, and prohibits their introduction into the State upon special grounds. It remains for us to consider whether those grounds are sufficient to justify it as an exception from the rule which would govern if they did not exist.

It may be material also to state in this connection that Congress had legislated on the general subject of interstate commerce by means of railroads prior to the date of the transaction

Opinion of the Court.

Section 5258 of the

on which the present suit is founded. Revised Statutes provides that "every railroad company in the United States whose road is operated by steam, its successors and assigns, is hereby authorized to carry upon and over its road, boats, bridges, and ferries all passengers, troops, government supplies, mails, freight, and property on their way from any State to another State, and to receive compensation therefor, and to connect with roads of other States so as to form continuous lines for the transportation of the same to the place of destination." In the case of Railroad Co. v. Richmond, 19 Wall. 584, this section, then constituting a part of the act of Congress of June 15, 1866, was considered. Referring to this act and the act of July 25, 1866, authorizing the construction of bridges over the Mississippi River, the court say: "These acts were passed under the power vested in Congress to regulate commerce among the several States, and were designed to remove trammels upon transportation between different States which had previously existed, and to prevent a creation of such trammels in future, and to facilitate railway transportation by authorizing the construction of bridges over the navigable waters of the Mississippi. But they were intended to reach trammels interposed by state enactments or by existing laws of Congress. The power to regulate commerce among the several States was vested in Congress in order to secure equality and freedom in commercial intercourse against discriminating state legislation." p. 589.

Congress had also legislated on the subject of the transportation of passengers and merchandise in chapter 6, title 48 of the Revised Statutes; §§ 4252 to 4289, inclusive, having reference, however, mainly to transportation in vessels by water. But $$ 4278 and 4279 relate also to the transportation of nitro-glycerine and other similar explosive substances by land or water, and either as a matter of commerce with foreign countries or among the several States. Section 4280 provides that "the two preceding sections shall not be so construed as to prevent any State, Territory, district, city or town within the United States from regulating or from prohibiting the traffic in or transportation of those substances between persons or

Opinion of the Court.

places lying or being within their respective territorial limits, or from prohibiting the introduction thereof into such limits for sale, use, or consumption therein."

So far as these regulations made by Congress extend, they are certainly indications of its intention that the transportation of commodities between the States shall be free, except where it is positively restricted by Congress itself, or by the States in particular cases by the express permission of Congress. On this point the language of this court in the case of County of Mobile v. Kimball, 102 U. S. 691, 697, is applicable. Repeating and expanding the idea expressed in the opinion in the case of Cooley v. Board of Port Wardens, 12 How. 299, this court said: "The subjects, indeed, upon which Congress can act under this power are of infinite variety, requiring for their successful management different plans or modes of treatment. Some of them are national in their character, and admit and require uniformity of regulation, affecting alike all the States; others are local, or are mere aids 'to commerce, and can only be properly regulated by provisions adapted to their special circumstances and localities. Of the former class may be mentioned all that portion of commerce with foreign countries or between the States which consists in the transportation, purchase, sale, and exchange of commodities. Here there can of necessity be only one system or plan of regulations, and that Congress alone can prescribe. Its non-action in such cases with respect to any particular commodity or mode of transportation is a declaration of its purpose that the commerce in that commodity, or by that means of transportation, shall be free. There would, otherwise, be no security against conflicting regulations of different States, each discriminating in favor of its own products and against the products of citizens of other States. And it is a matter of public history that the object of vesting in Congress the power to regulate commerce with foreign nations and among the States was to insure uniformity of regulation against conflicting and discriminating state legislation." Also, (p. 702 :) "Commerce with foreign countries and among the States, strictly considered, consists in intercourse and traffic, including