Offenses charged under 18 U.S.C. § 1621 and § 1623 share four common elements, which are discussed below. That discussion is followed by an analysis of the differences between the two statutes. Note that 28 U.S.C. § 1746, added in 1976, allows certain unsworn declarations to be made subject to the penalties of perjury, with corresponding changes made to sections 1621 and 1623. Perjury at trial also may be considered at sentencing under the Sentencing Guidelines, even when not considered as a separate count by the jury. If a convicted defendant commits perjury before the grand jury or court in the proceeding which led to conviction, the government may demonstrate the elements of a section 1621 perjury offense to the sentencing judge and accordingly ask for imposition of the obstruction of justice sentencing enhancement.
[cited in JM 9-69.200]