This crime, established by Article III, Section 3 of the Constitution, is the only one specifically created by the document. The crime occurs when one "levies war" against the United States or gives "aid and comfort" to its enemies.
A person can be convicted of treason only if he or she confesses, or if there are two witnesses to the act of treason. Treason is also a ground for impeachment of the President or other federal officials.
www.justicelearning.org, The United States Constitution, what it says, what it means, A Hip Pocket Guide (Oxford University Press)