'912.] OF THE UNITED STATES. 319 



aid of legislation is equivalent to an Act of Congress, and while in 

 force constitutes a part of the Supreme power of the land. Foster 

 z's. Neilson."^''* Mr. Justice Field dissented on the ground that the 

 act was too plain to permit of any interpretation consistent with the 

 treaty. As to the principle regulating the subject, he said: 



" A treaty is in its nature a contract between two or more nations, and 

 is so considered by the writers on public law; and by the Constitution it is 

 placed on the same footing and made of like obligation as a law of the 

 United States. Both are declared in that instrument to be the supreme law 

 of the land, and no paramount authority is given to either over the other. 



" Some treaties operate in whole or in part by their own force, and some 

 require legislation to carry their stipulations into effect. ... If the treaty 

 relates to a subject within the power of Congress and operates by its own 

 force, it can only be regarded by the Courts as equivalent to a legislative act. 

 Congress may, as with an ordinary statute, modify its provisions, or supersede 

 them altogether."""* 



Here is language directly contrary to the modern essayist's idea of 

 the openness of the question whether a treaty may deal with a sub- 

 ject committed to Congress. "If," says Mr. Justice Field, and on 

 that point the whole Court concurred, "the treaty relates to a sub- 

 ject zvithin the pozver of Congress and operates by its ozmi force, it 

 can only be regarded by the courts as equivalent to a legislatiz'c act." 

 After Congress had, in 1888, as above stated, unqualifiedly legis- 

 lated against the return of Chinese laborers who had once left this 

 country, the Supreme Court in Chae Chan Ping vs. United States,^^® 

 sustained the constitutionality of this statute. Mr. Justice Field 

 delivered the opinion of the Court, and said: 



" It must be conceded that the Act of 1888 is in contravention of express 

 stipulations of the treaty of 1868 and of the supplemental treaty of 1880, 

 but it is not on that account invalid or to be restricted in its enforcement. 

 The treaties were of no greater legal obligation than the Act of Congress. 

 By the Constitution, laws made in pursuance and treaties made under the 

 authority cff the United States are both declared to be the supreme law of 

 the land, and no paramount authority is given to one over the other. ... If 

 the treaty operates by its own force, and relates to'^a subject within the powers 

 of Congress, it can be deemed in that particular only the equivalent of a 

 legislative Act, to be repealed or modified at the pleasure of Congress. In 

 either case the last expression of the sovereign will must control.""' 



"-Ibid., p. 540. "" 130 U. S., 581 (1880). 



"' Ibid., pp. 562-3. "' Ibid., p. 600. 



