10 U.S.C. § 903b: Art. 103b. Aiding the enemy

Any person who—(1) aids, or attempts to aid, the enemy with arms, ammunition, supplies, money, or other things; or (2) without proper authority, knowingly harbors or protects or gives intelligence to, provides military education, military training, or tactical advice to, or communicates or corresponds with or holds any intercourse with the enemy, either directly or indirectly; shall suffer death or such other punishment as a court-martial or military commission may direct. This section does not apply to a military commission established under chapter 47A of this title.