that no tax or duty shall be laid on articles exported from any State; in consequence of which qualification, it now only extends to the DUTIES ON IMPORTS. This answers to the second case. The third will be found in that clause which declares that Congress shall have power "to establish an UNIFORM RULE of naturalization throughout the United States." This must necessarily be exclusive; because if each State had power to prescribe a DISTINCT RULE, there could not be a UNIFORM RULE.
A case which may perhaps be thought to resemble the latter, but which is in fact widely different, affects the question immediately under consideration. I mean the power of imposing taxes on all articles other than exports and imports. This, I contend, is manifestly a concurrent and coequal authority in the United States and in the individual States. There is plainly no expression in the granting clause which makes that power EXCLUSIVE in the Union. There is no independent clause or sentence which prohibits the States from exercising it. So far is this from being the case, that a plain and conclusive argument to the contrary is to be deduced from the restraint laid upon the States in relation to duties on imports and exports. This restriction implies an admission that, if it were not inserted, the States would possess the power it excludes; and it implies a further admission, that as to all other taxes, the authority of the States remains undiminished. In any other view it would be both unnecessary and dangerous; it would be unnecessary, because if the grant to the Union of the power of laying such duties implied the exclusion of the States, or even their subordination in this particular, there could be no need of such a restriction; it would be dangerous, because the introduction of it leads directly to the conclusion which has been mentioned, and which, if the reasoning of the objectors be just, could not have been intended; I mean that the States, in all cases to which the restriction did not apply, would have a concurrent power of taxation with the Union. The restriction in question amounts to what lawyers call a NEGATIVE PREGNANT that is, a NEGATION of one thing,