Breaking allegiance to the U.S. government, through acts of war against it or aiding its enemy.
Article III, section 3, of the Constitution limits treason to acts of war against the United States or giving aid and comfort to its enemies. The crime must be proved by the testimony of at least two witnesses to the same overt act or by the defendant’s confession in open court. Treason is the only federal crime for which both the substantive and evidential elements of culpability are spelled out in the Constitution. By defining the crime narrowly, the Framers sought to prevent the political abuse of treason law.
The Whiskey Rebellion and Fries Rebellion in the 1790’s resulted in three treason convictions in the federal circuit court for Pennsylvania, but presidential pardons for all the defendants forestalled appeals to the Supreme Court. The Court’s first ruling on the treason clause came in Ex parte Bollmann
No treason convictions were appealed to the Court before World War II, a conflict that raised several key issues. In Cramer v. United States
Chapin, Bradley. The American Law of Treason: Revolutionary and Early National Origins. Seattle: University of Washington Press, 1964. Hurst, James Willard. The Law of Treason in the United States. Westport, Conn.: Greenwood Press, 1971. Kennedy, Roger G. Burr, Hamilton, and Jefferson: A Study in Character. New York: Oxford University Press, 2000. Lomask, Milton. Aaron Burr: The Conspiracy and the Years of Exile, 1805-1836. New York: Farrar, Straus, Giroux, 1982.
World War II