Section 3: Treason

Section 3 defines treason and limits its punishment.

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. 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 attainted.

The Constitution defines treason as specific acts, namely "levying War against the United States, or in adhering to their Enemies, giving them Aid and Comfort." A contrast is therefore maintained with the English law, whereby crimes including conspiring to kill the King or "violating" the Queen, were punishable as treason. In Ex Parte Bollman, 8 U.S. 75 (1807), the Supreme Court ruled that "there must be an actual assembling of men, for the treasonable purpose, to constitute a levying of war."

Under English law effective during the ratification of the U.S. Constitution, there were several species of treason. Of these, the Constitution adopted only two: levying war and adhering to enemies. Omitted were species of treason involving encompassing (or imagining) the death of the king, certain types of counterfeiting, and finally fornication with women in the royal family of the sort which could call into question the parentage of royal successors. James Wilson wrote the original draft of this section, and he was involved as a defense attorney for some accused of treason against the Patriot cause. The two forms of treason adopted were both derived from the English Treason Act 1351. Joseph Story wrote in his Commentaries on the Constitution of the United States of the authors of the Constitution that:

they have adopted the very words of the Statute of Treason of Edward the Third; and thus by implication, in order to cut off at once all chances of arbitrary constructions, they have recognized the well-settled interpretation of these phrases in the administration of criminal law, which has prevailed for ages.

In Federalist No. 43 James Madison wrote regarding the Treason Clause:

As treason may be committed against the United States, the authority of the United States ought to be enabled to punish it. But as new-fangled and artificial treasons have been the great engines by which violent factions, the natural offspring of free government, have usually wreaked their alternate malignity on each other, the convention have, with great judgment, opposed a barrier to this peculiar danger, by inserting a constitutional definition of the crime, fixing the proof necessary for conviction of it, and restraining the Congress, even in punishing it, from extending the consequences of guilt beyond the person of its author.

Based on the above quotation, it was noted by the lawyer William J. Olson in an amicus curiae in the case Hedges v. Obama that the Treason Clause was one of the enumerated powers of the federal government. He also stated that by defining treason in the U.S. Constitution and placing it in Article III "the founders intended the power to be checked by the judiciary, ruling out trials by military commissions. As James Madison noted, the Treason Clause also was designed to limit the power of the federal government to punish its citizens for 'adhering to the enemies of the United States by, giving them aid and comfort.'"

Section 3 also requires the testimony of two different witnesses on the same overt act, or a confession by the accused in open court, to convict for treason. This rule was derived from another English statute, the Treason Act 1695. The English law did not require both witnesses to have witnessed the same overt act; this requirement, supported by Benjamin Franklin, was added to the draft Constitution by a vote of 8 states to 3.

In Cramer v. United States, 325 U.S. 1 (1945), the Supreme Court ruled that "every act, movement, deed, and word of the defendant charged to constitute treason must be supported by the testimony of two witnesses." In Haupt v. United States, 330 U.S. 631 (1947), however, the Supreme Court found that two witnesses are not required to prove intent, nor are two witnesses required to prove that an overt act is treasonable. The two witnesses, according to the decision, are required to prove only that the overt act occurred (eyewitnesses and federal agents investigating the crime, for example).

Punishment for treason may not "work Corruption of Blood, or Forfeiture except during the Life of the Person" so convicted. The descendants of someone convicted for treason could not, as they were under English law, be considered "tainted" by the treason of their ancestor. Furthermore, Congress may confiscate the property of traitors, but that property must be inheritable at the death of the person convicted.