Where, by federal license, an occupation has been authorized by the United States, enjoyment and employment of the license may not bo re-trained by a State. Thus in Moran v. New Orleans16 was held void an ordinance of the city of New Orleans imposing a license rax on certain vessels engaged in foreign commerce and duly enrolled and licensed under act of Congress. The court say: "The sole occupation sought to be subjected to the tax is that of using and enjoying the license of the United States to employ these particular vessels in the coasting trade; and the State thus seeks to burden with an exaction, fixed at its own pleasure, the very right to which the plaintiff in error is entitled under and which he derives from the constitution and laws of the United States. The Louisiana statute declares expressly that if he refuses or neglects to pay the license tax imposed upon him, for using his boat in this way, he shall not be permitted to act under and avail himself of the license granted by the United States, but may be enjoined from so doing by judicial process. The conflict between the two authorities is direct and express. ... In such an opposition, the only question is which is the superior authority; and reduced to that it furnishes its own answer."

In Harman v. Chicago17 this doctrine is approved and again applied.

14 Justices White and Day dissented.

15 Ozan Lumber Co. v. Union Co. Nat. Bank (145 Fed. 344).

16 112 U. S. 69: 5 Sup. Ct. Rep. 38; 28 L. ed. MR

17 147 U. S. 396; 13 Sup. Ct. Rep. 306; 37 L. ed. 216.