Constitution of the United States of America
Article III: Judicial Branch
Article 3, Section 3:  Definition and Penalty for Treason

 Treason against the United States, shall consist only in
levying War against them, or in adhering to their Enemies, giving
them Aid and Comfort.

3.3.2  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.

3.3.3  The Congress shall have Power to declare the
Punishment of Treason, but no Attainder of Treason shall work
Corruption of Blood, or Forfeiture except during the Life of the
Person attained.