The Commentary that accompanies the guideline sections may serve a number of purposes. First, it may interpret the guideline or explain how it is to be applied. Failure to follow such commentary could constitute an incorrect application of the guidelines, subjecting the sentence to possible reversal on appeal. See 18 U.S.C. § 3742. Second, the commentary may suggest circumstances which, in the view of the Commission, may warrant departure from the guidelines. Such commentary is to be treated as the legal equivalent of a policy statement. Finally, the commentary may provide background information, including factors considered in promulgating the guideline or reasons underlying promulgation of the guideline. As with a policy statement, such commentary may provide guidance in assessing the reasonableness of any departure from the guidelines.
Portions of this document not labeled as guidelines or commentary also express the policy of the Commission or provide guidance as to the interpretation and application of the guidelines. These are to be construed as commentary and thus have the force of policy statements.
"[C]ommentary in the Guidelines Manual that interprets or explains a guideline is authoritative unless it violates the Constitution or a federal statute, or is inconsistent with, or a plainly erroneous reading of, that guideline." Stinson v. United States, 508 U.S. 36, 38 (1993).