levying of import duties which have been voted by congress, the federal court must decide the case, because it arises under the interpretation of a law of the United States.
This rule is in perfect accordance with the fundamental principles of the federal constitution. The Union as it was established in 1789, possesses, it is true, a limited supremacy; but it was intended that within its limits it should form one and the same people.[148] Within those limits the Union is sovereign. When this point is established and admitted, the inference is easy; for if it be acknowledged that the United States constitute one and the same people within the bounds prescribed by their constitution, it is impossible to refuse them the rights which belong to other nations. But it has been allowed, from the origin of society, that every nation has the right of deciding by its own courts those questions which concern the execution of its own laws. To this it is answered, that the Union is in so singular a position, that in relation to some matters it constitutes a people, and that in relation to all the rest it is a nonentity. But the inference to be drawn is, that in the laws relating to these matters the Union possesses all the rights of absolute sovereignty. The difficulty is to know what these matters are; and when once it is resolved (and we have shown how it was resolved, in speaking of the means of determining the jurisdiction of the federal courts), no farther doubt can arise; for as soon as it is established that a suit is federal, that is to say, that it belongs to the share of sovereignty reserved by the constitution to the Union, the natural consequence is that it should come within the jurisdiction of a federal court.
Whenever the laws of the United States are attacked, or whenever they are resorted to in self-defence, the federal courts must be appealed to. Thus the jurisdiction of the tribunals of the Union extends and narrows its limits exactly in the same ratio as the sovereignty of the Union augments or decreases. We have shown that the principal aim of the legislators of 1789 was to divide the sovereign authority into two parts. In the one they placed the control of all the general interests of the Union, in the other the control of the special interest of its component states. Their chief solicitude was to arm the federal government with sufficient power to enable it to resist, within its sphere, the encroachments of the several states. As for these communities, the principle of independence within certain limits of their own was adopted in their behalf; and they were concealed from the inspection, and protected from the control, of the central government. In speaking of the division of the authority, I observed that this latter principle had not always been held sacred, since the states are prevented from passing certain laws, which apparently belong to their own particular sphere of interest. When a state of the Union passes a law of this kind, the citizens who are injured by its execution can appeal to the federal courts.