may be true, but Congress is amply authorized to pass measures to protect interstate commerce if legislation of that character is needed.” And again, in the
Shafer case (supra, at pp. 188, 198), the Court said: “The right to buy it [grain] for shipment, and to ship it in interstate commerce is not a privilege derived from state laws and which they may fetter with conditions, but is a common right, the regulation of which is committed to Congress and denied to the States by the commerce clause of the Constitution.”
The fact that intrastate and interstate transactions are commingled on the tobacco market does not frustrate or restrict the congressional power to protect and control what is committed to its own care. As we said in the Shreveport case, 234 U. S. 342, 351, 352, with respect to the intrastate rates of interstate carriers — “Wherever the interstate and intrastate transactions of carriers are so related that the government of the one involves the control of the other, it is Congress, and not the State, that is entitled to prescribe the final and dominant rule, for otherwise Congress would be denied the exercise of its constitutional authority and the State, and not the Nation, would be supreme within the national field.” See, also, Minnesota Rate Cases, 230 U. S. 352, 399; Wisconsin Railroad Comm’n v. Chicago, B. & Q. R. Co., 257 U. S. 563, 588; Stafford v. Wallace, supra, at p. 522. Here, the transactions on the tobacco market were conducted indiscriminately at virtually the same time, and in a manner which made it necessary, if the congressional rule were to be applied, to make it govern all the tobacco thus offered for sale.
■ Having this authority to regulate the sales on the to-, bacco market, Congress could prescribe the conditions under which the sales should be made in order to give protection to sellers or purchasers or both. Congress is not to be denied the exercise of its .constitutional author