2005 Federal Sentencing Guidelines
Chapter 2 - PART X - OTHER OFFENSES 
§2X2.1. Aiding and Abetting 
The offense level is the same level as that for the underlying offense.
Commentary
Statutory Provisions: 18
  U.S.C. §§ 2, 2339, 2339A, 2339C(a)(1)(A).
Application Note:
1. Definition.—For
  purposes of this guideline,"underlying offense" means the offense the defendant
  is convicted of aiding or abetting, or in the case of a violation of 18 U.S.C. § 2339A
  or § 2339C(a)(1)(A), "underlying offense" means the offense the defendant
  is convicted of having materially supported or provided or collected funds
  for, prior to or during its commission.
Background: A defendant convicted
  of aiding and abetting is punishable as a principal. 18 U.S.C. § 2.
  This section provides that aiding and abetting the commission of an offense
  has the same offense level as the underlying offense. An adjustment for a mitigating
  role (§3B1.2) may be applicable.
Historical Note: Effective
  November 1, 1987. Amended effective November 1, 1990 (see Appendix
  C, amendment 359); November 1, 2002 (see Appendix
  C, amendment 637); November 1, 2003 (see Appendix
  C, amendment 655).