All this is in full accordance with the doctrine of Gibbons v. Ogden, that Congress in exercising its powers of commercial regulations, and the States in exercising other sovereign powers reserved to them, may pass laws substantially similar or even identical in their provisions. Furthermore, it states expressly the principle, necessarily implied in this doctrine, that in all doubtful cases the intention of the Legislature must be looked to, to determine whether the given enactment is a regulation of foreign or interstate commerce, or an emanation from some other sovereign power; and that where the law purports to emanate from a well-recognized power possessed by the States, it should not be held a regulation of foreign or interstate commerce, unless the intention to regulate such commerce is clearly shown.
The result, then, of the License Cases and Passenger Cases, as far as they bear upon the question of what constitutes a regulation of foreign or interstate commerce, seems to be simply this: Chief-Justice Taney, in both cases, lays down the doctrine that any law which directly affects foreign or interstate commerce is a regulation of such commerce, and that the intention with which the law was passed is entirely immaterial. Justice Woodbury maintains the theory that a State law operating upon foreign or interstate commerce cannot be deemed a regulation of such commerce when passed diverso intuitu; or, in other words, that the purpose and not the operative effect of the law determines whether it is a regulation of foreign or interstate commerce or not. The other judges do not go into any general reasoning upon the subject.
The next case that we need consider is the case of Cooley v. Board of Port Wardens, 12 How. 299. In that case the long controversy over the question of concurrency or exclusiveness was at last settled. The Court reached the conclusion that the power to regulate foreign or interstate commerce was partly exclusive and partly concurrent. The case involved the constitutionality of a State pilotage law. The Court sustained the constitutionality of the law on the ground that the power to regulate foreign or interstate commerce was concurrent, as far as it concerns regulations local in their operation and effect, and that the pilotage law was a regulation of that character. The Court, in this case, lay down the principle that the power to regulate foreign or interstate commerce is in part “exclusive” and in part “concurrent,” — “exclusive” as to subjects of the power in their nature