Treason

The United States Constitution

Article III Section 3 - Treason against the United States, shall consist only in levying War against
them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the Testimony of two Witnesses to the
same overt Act, or on Confession in open Court.

Article I Section 8 - To define and punish Piracies and Felonies committed on the high Seas, and Offenses against the Law of Nations;

THE LAW OF NATIONS
PRELIMINARIES

IDEA AND GENERAL PRINCIPLES OF THE LAW OF NATIONS - § 1. What is meant by a nation or state.
NATIONS or states are bodies politic, societies of men united together for the purpose of promoting their mutual safely and advantage by the joint efforts of their combined strength.

IDEA AND GENERAL PRINCIPLES - § 22. Right of nations against the infractors of the law of nations.
The laws of natural society are of such importance to the safety of all states, that, if the custom once prevailed of trampling them under foot, no nation could flatter herself with the hope of preserving her national existence, and enjoying domestic tranquility, however attentive to pursue every measure dictated by the most consummate prudence, justice, and moderation.