HAR VARD LA W RE VIE W.
decide this question. The court itself would hardly assume the prerogatives. There is nothing left but to construe the action or inaction of Congress upon the subject. Perhaps the case of the infected rags may be distinguished from that of intoxicating liquors, upon the ground that the inaction of Congress is to be construed differently upon the two subjects.^
Having seen that the power of Congress to regulate commerce does not deprive the States of the right to enact quarantine laws in the absence of express legislation by Congress upon the subject, we will now inquire what limitations that power of regulating imposes upon the scope of the provisions of such laws. Only with great hesitation can any generalization be offered upon a subject as yet so inchoate and undeveloped by decisions, at the same time so important as involving the limits of State power. Some limit, however, there must be. It cannot be permitted that a State, although legislating upon an appropriate subject, should embarrass the commerce of the whole country by unnecessary and indiscriminate legislation. It would be equally improper to deny to a State legislative power to the extent necessary to render effective laws upon subjects appropriate to the States. Between these limits two rules are conceivable : first, to allow the States any reasonable regulations ; second, any absolutely necessary regulations. In such a matter, however, as State interference with foreign and national commerce, it may be said that only that legislation is reasonable which is absolutely necessary. Of course a court would be very loath to decide that a particular regulation of a quarantine law was unnecessary for the protection of health. Yet, however delicate the questions involved, the provisions of a quar- antine law are legally no more sacred than any other police regu- lation ; and after every reasonable presumption in favor of their validity, the court is still bound to use its common sense in the matter. The question is. When do State regulations of foreign and interstate commerce permissible in regard to their subject become unconstitutional on account of their scope } The Consti- tution-makers dealt with just this question in the case of State inspection laws, and have given an express rule in that instance : "No State shall, without the consent of the Congress, lay any imposts or duties on imports or exports, except what may be absolutely
��1 See U. S. Rev. Sut., Tit. Iviii., recognizing the health laws of the States.