RE: Link to where SCOTUS said that?

Posted on: June 7, 2017 at 13:12:22 CT

It results that the investment of the federal government with the powers of external sovereignty did not depend upon the affirmative grants of the Constitution. The powers to declare and wage war, to conclude peace, to make treaties, to maintain diplomatic relations with other sovereignties, if they had never been mentioned in the Constitution, would have vested in the federal government as necessary concomitants of nationality. Neither the Constitution nor the laws passed in pursuance of it have any force in foreign territory unless in respect of our own citizens (see American Banana Co. v. United Fruit Co., 213 U. S. 347, 213 U. S. 356), and operations of the nation in such territory must be governed by treaties, international understandings and compacts, and the principles of international law. As a member of the family of nations, the right and power of the United States in that field are equal to the right and power of the other members of the international family. Otherwise, the United States is not completely sovereign. The power to acquire territory by discovery and occupation (Jones v. United States, 137 U. S. 202, 137 U. S. 212), the power to expel undesirable aliens (Fong Yue Ting v. United States, 149 U. S. 698, 149 U. S. 705 et seq.), the power to make such international agreements as do not constitute treaties in the constitutional sense (Altman & Co. v. United States, 224 U. S. 583, 224 U. S. 600-601; Crandall, Treaties, Their Making and Enforcement,2d ed., p. 102 and note 1), none of which is expressly affirmed by the Constitution, nevertheless exist as inherently inseparable from the conception of nationality. This the court recognized, and, in each of the cases cited, found the warrant for its conclusions not in the provisions of the Constitution, but in the law of nations.

https://supreme.justia.com/cases/federal/us/299/304/case.html