Article I, Section 8, Clause 10:
[The Congress shall have Power . . .] To define and punish Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations; . . .
When the United States ceased to be a part of the British empire, and assumed the character of an independent nation, they became subject to that system of rules which reason, morality, and custom had established among civilized nations of Europe, as their public law. . . . The faithful observance of this law is essential to national character. . . .1 These words of the Chancellor Kent expressed the view of the binding character of international law that was generally accepted at the time the Constitution was adopted. During the Revolutionary War, Congress took cognizance of all matters arising under the law of nations and professed obedience to that law.2 Under the Articles of Confederation, it was given exclusive power to appoint courts for the trial of piracies and felonies committed on the high seas, but no provision was made for dealing with offenses against the law of nations.3 The draft of the Constitution submitted to the Convention of 1787 by its Committee of Detail empowered Congress
to declare the law and punishment of piracies and felonies committed on the high seas, and the punishment of counterfeiting the coin of the United States, and of offences against the law of nations.4 In the debate on the floor of the Convention, the discussion turned on the question as to whether the terms,
felonies and the
law of nations, were sufficiently precise to be generally understood. The view that these terms were often so vague and indefinite as to require definition eventually prevailed and Congress was authorized to define as well as punish piracies, felonies, and offenses against the law of nations.5