18 U.S.C. § 2247: Repeat offenders

(a) Maximum Term of Imprisonment.—The maximum term of imprisonment for a violation of this chapter after a prior sex offense conviction shall be twice the term otherwise provided by this chapter, unless section 3559(e) applies. (b) Prior Sex Offense Conviction Defined.—In this section, the term “prior sex offense conviction” has the meaning given that term in section 2426(b).