THE CHILD LABOR LAW CASE 57 " In interpreting the Constitution it must never be forgotten that the nation is made up of states to which are entrusted the powers of local government. ... To sustain this statute would not be in our judg- ment a recognition of the lawful exertion of congressional authority over interstate commerce, but would sanction an invasion by the federal power of the control of a matter purely local in its character, and over which no authority has been delegated to Congress in conferring the power to regulate commerce among the states. . . . " In our view the necessary effect of this act is, by means of a pro- hibition against the movement in interstate commerce of ordinary commercial commodities, to regulate the hours of labor of children in factories and mines within the states, a purely state authority. . . . The far-reaching result of upholding the act cannot be more plainly in- dicated than by pointing out that if Congress can thus regulate matters entrusted to local authority by prohibition of the movement of commod- ities in interstate commerce, all freedom of commerce will be at an end, and the power of the states over local matters may be eliminated, and thus our system of government be practically destroyed." It is to be noted that the doctrine thus announced is that the natural and necessary effect of the statute upon pure matters of interstate commerce is to be wholly disregarded. This doctrine is entirely new. Looking to the substance and disregarding the form, closely in- vestigating the purpose and ulterior motiyes of Congress, paying strict heed to the natural and necessary effect of the statute, as- suredly it operates on the interstate transportation of child-made goods. Whatever else it does indirectly, in terms it rules only interstate transportation. And this is done to remove the evils involved in such transportation. Still regarding the substantial effect, the statute in terms does not prohibit manufacture and does not regulate hours of labor. The manufacturer may produce as he pleases and employ whom he pleases. The manufacturer, who does not ship outside the state, — and sending goods across state lines is not a right which the state can guarantee, — need never know of the existence of the federal statute. The state may make such regulations as it wishes concerning the employment of children. There is no coer- cion upon it. The federal statute functions only when the inter- state transportation begins, that is, only when the jurisdiction of the state ceases to attach.
