The first United States statute dealing with accessory liability was passed in 1790, and made criminally liable those who should aid and assist, procure, command, counsel or advise murder or robbery on land or sea, or piracy at sea. United States v. Peoni, 100 F.2d 401, 402 (2d Cir. 1938). This was broadened in 1870, to include any felony, and by it an accessory was anyone who counsels, advises or procures the crime. Id. These early statutes were repealed in 1909, and supplanted by 18 U.S.C. § 550, a statute which included the modern language of "Whoever aids, abets, counsels, commands, induces, or procures the commission of an offense is a principal." Id.
In 1948, § 550, became 18 U.S.C. § 2(a). Section 2(b) was also added to make clear the legislative intent to punish as a principal not only one who directly commits an offense and one who "aids, abets, counsels, commands, induces or procures" another to commit an offense, but also anyone who causes the doing of an act which if done by him directly would render him guilty of an offense against the United States. 18 U.S.C. § 2 (Historical and Revision Notes). It removes all doubt that one who puts in motion or assists in the illegal enterprise or causes the commission of an indispensable element of the offense by an innocent agent or instrumentality is guilty as a principal even though he intentionally refrained from the direct act constituting the completed offense. United States v. Dodd, 43 F.3d 759, 763 (1st Cir. 1995).
Subsection (a) of Section 2 was amended to its current form in 1951 to read, "Whoever commits an offense against the United States or aids, abets, counsels, commands, induces or procures its commission, is punishable as a principal." Subsection (b) was also amended in 1951 to add "wilfully" and "is punishable as a principal."
[updated October 1998]