The power of Congress with reference to both the definition and punishment of treason is limited by Section III of Article III of the Constitution. The three clauses of this section provide as follows:
"Treason against the United States shall consist in levying war against them, 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." 90
The purpose of these provisions is to exclude the possibility of the Federal Government, through either its judicial or legislative branches, following the precedents of English law and practice, and declaring a great variety of acts to constitute treason and punishable as such.
Following in the main the words of the Constitution Congress has by statute declared that "whoever, owing allegiance to the United States levies war against them, or adheres to their enemies giving them aid and comfort within the United States or elsewhere, is guilty of treason."91
90 Art. III, Sec. ITT.
91 35 Stat. at L., chap. 321, p. 1088, § 1. The phraseology of section 5331 of the Rev. Stat. is here slightly changed. By section 2, the punishment for treason is fixed at death, or, at the discretion of the court, imprisonment at hard labor for not less than four years, and a tine of not less than ten thousand dollars, and disqualification from holding office under the United States.