Page:Joseph Story, Commentaries on the Constitution of the United States (1st ed, 1833, vol I).djvu/469

 CH. V.] § 445. On the other hand, it has been maintained with great pertinacity, that the slates possess concurrent authority with congress in all cases, where the power is not expressly declared to he exclusive, or expressly prohibited to the states; and if, in the exercise of a concurrent power, a conflict arises, there is no reason, why each should not be deemed equally rightful. But it is plain, that this reasoning goes to the direct overthrow of the principle of supremacy; and, if admitted, it would enable the subordinate sovereignty to annul the powers of the superior. There is a plain repugnance in conferring on one government a power to control the constitutional measures of another, which other, with respect to these very measures, is declared to be supreme over that, which exerts the control. For instance, the states have acknowledgedly a concurrent power of taxation. But it is wholly inadmissible to allow that power to be exerted over any instrument employed by the general government to execute its own powers; for such a power to tax involves a power to destroy; and this power to destroy may defeat, and render useless the power to create. Thus a state may not tax the mail, the mint, patent rights, custom-house papers, or judicial process of the courts of the United States. And yet there is no clause in the constitution, which prohibits the states from exercising the power; nor any exclusive grant to the United States. The apparent repugnancy creates, by implication, the prohibition. So congress, by the constitution, possess power to provide for governing such part of