Whoever commits an offense against the United States or aids, abets, counsels, commands, induces or procures its commission, is punishable as a principal.

Whoever willfully causes an act to be done which if directly performed by him or another would be an offense against the United States, is punishable as a principal.

(June 25, 1948, ch. 645, 62 Stat. 684; Oct. 31, 1951, ch. 655, § 17b, 65 Stat. 717.)