Page:Joseph Story, Commentaries on the Constitution of the United States (1st ed, 1833, vol I).djvu/463

 CH. V.] pursuance of it shall be the supreme law of the land; it would be absurd to say, that a state law, repugnant to it, might have concurrent operation and validity; and especially, as it is expressly added, any thing in the constitution or laws of any state to the contrary notwithstanding. The repugnancy, then, being made out, it follows, that the state law is just as much void, as though it had been expressly declared to be void; or the power in congress had been expressly declared to be exclusive. Every power given to congress is by the constitution necessarily supreme; and if, from its nature, or from the words of the grant, it is apparently intended to be exclusive, it is as much so, as if the states were expressly forbidden to exercise it.

§ 438. The principal difficulty lies, not so much in the rule, as in its application to particular cases. Here, the field for discussion is wide, and the argument upon construction is susceptible of great modifications, and of very various force. But unless, from the nature of the power, or from the obvious results of its operations, a repugnancy must exist, so as to lead to a necessary conclusion, that the power was intended to be exclusive, the true rule of interpretation is, that the power is merely concurrent. Thus, for instance, an affirmative power in congress to lay taxes, is not necessarily incompatible with a like power in the States. Both may exist without interference; and if any interference should arise in a particular case, the question of supremacy would turn, not upon the nature of the power, but upon supremacy of right in the exercise of the power in that case. In our complex system, presenting