Every government, whatever may be its constitution, requires the means of constraining its subjects to discharge their obligations, and of protecting its privileges from their assaults. As far as the direct action of the government on the community is concerned, the constitution of the United States contrived, by a master-stroke of policy, that the federal courts, acting in the name of the laws, should only take cognizance of parties in an individual capacity. For, as it had been declared that the Union consisted of one and the same people within the limits laid down by the constitution, the inference was that the government created by this constitution, and acting within these limits, was invested with all the privileges of a national government, one of the principal of which is the right of transmitting its injunctions directly to the private citizen. When, for instance, the Union votes an impost, it does not apply to the states for the levying of it, but to every American citizen, in proportion to his assessment. The supreme court, which is empowered to enforce the execution of this law of the Union, exerts its influence not upon a refractory state, but upon the private taxpayer; and, like the judicial power of other nations, it is opposed to the person of an individual. It is to be observed that the Union chose its own antagonist; and as that antagonist is feeble, he is naturally worsted. But the difficulty increases when the proceedings are not brought forward _by_ but _against_ the Union. The constitution recognizes the legislative power of the state; and a law so enacted may impair the privileges of the Union, in which case a collision is unavoidable between that body and the state which had passed the law; and it only remains to select the least dangerous remedy, which is very clearly deducible from the general principles I have before established.[151] It may be conceived that, in the case under consideration, the Union might have sued the state before a federal court, which would have annulled the act; and by this means it would have adopted a natural course of proceeding: but the judicial power would have been placed in open hostility to the state, and it was desirable to avoid this predicament as much as possible. The Americans hold that it is nearly impossible that a new law should not impair the interests of some private individuals by its provisions: these private interests are assumed by the American legislators as the ground of attack against such measures as may be prejudicial to the Union, and it is to these cases that the protection of the supreme court is extended.