"It need hardly be said that a treaty cannot change the Constitution or be held valid if it be in violation of that instrument." The Cherokee Tobacco, 11 Wall. ( 78 U.S.), 616, 620 (1871).
"It would be manifestly contrary to the objectives of those who created the Constitution, as well as those who were responsible for the Bill of Rights--let alone alien to our entire constitutional history and tradition--to construe Article VI as permitting the United States to exercise power under an international agreement without observing constitutional prohibitions. In effect, such construction would permit amendment of that document in a manner not sanctioned by Article V." - 354 U.S. 1 (1957)
"The treaty is . . . a law made by the proper authority, and the courts of justice have no right to annul or disregard any of its provisions, unless they violate the Constitution of the United States." Doe v. Braden, 57 U.S. (16 How.) 635, 656 (1853) 