He insists that the present levy is not a true tax, but a penalty imposed for the purpose of suppressing traffic in a certain noxious type of firearms, the local regulation of which is reserved to the states because not granted to the national government. The cumulative effect on the distribution of a limited class of firearms, of relatively small value, by the successive imposition of different taxes, one on the Page 513 business of the importer or manufacturer, another on that of the dealer, and a third on the transfer to a buyer, is said to be prohibitive in effect and to disclose unmistakably the legislative purpose to regulate rather than to tax. The case is not one where the statute contains regulatory provisions related to a purported tax in such a way as has enabled this Court to say in other cases that the latter is a penalty resorted to as a means of enforcing the regulations. Nor is the subject of the tax described or treated as criminal by the taxing statute. On its face it is only a taxing measure, and we are asked to say that the tax, by virtue of its deterrent effect on the activities taxed, operates as a regulation which is beyond the congressional power.
Every tax is in some measure regulatory.
To some extent it interposes an economic impediment to the activity taxed as compared with others not taxed. Inquiry into the hidden motives which may move Congress to exercise a power constitutionally conferred upon Page 514 it is beyond the competency of courts. They will not undertake, by collateral inquiry as to the measure of the regulatory effect of a tax, to ascribe to Congress an attempt, under the guise of taxation, to exercise another power denied by the Federal Constitution. Magnano Co. v. Hamilton, supra, 45. We are not free to speculate as to the motives which moved Congress to impose it, or as to the extent to which it may operate to restrict the activities taxed.