Several statutes that outlaw federal sex offenses insist upon a minimum term of imprisonment. In United States Sentencing Commission survey which addressed mandatory minimum sentences in child pornography cases but not other sex offense cases, a majority of the judges responding to a United States Sentencing Commission survey thought that the mandatory minimum sentences for production and distribution of child pornography and other child exploitation offenses were generally appropriate. Well over two-thirds, however, considered those for receipt of child pornography too high. The Commission's report on mandatory minimum sentencing statutes noted that its "review of available sentencing data [relating to sex offenses] indicates that further study of these penalties is needed before it can offer specific recommendations in this area." Constitutional Considerations

Defendants sentenced to mandatory minimum terms of imprisonment have challenged them on a number of constitutional grounds ranging from Congress's legislative authority, to cruel and unusual punishment, through ex post facto and double jeopardy, to equal protection and due process. Federal Enclaves and Prisons

Most of the mandatory minimum penalties for federal sex offenses appear in one of three chapters of title 18 of the United States Code. Chapter 109A outlaws rape and other forms of sexual abuse and sexual contact when committed in federal enclaves or federal prisons. Chapter 109A Offenses

Chapter 109A violations trigger mandatory minimum sentencing provisions when:
the offender commits or attempts to commit a sexual act by force or threat or by rendering the victim unconscious or intoxicated (aggravated sexual abuse); a sexual act is committed against a minor under the age of 12, or under the age of 16, if is there is disparity of 4 years or more between the age of the victim and the age of the offender (aggravated sexual abuse of a child); the offender commits or attempts to commit a sexual act by threat or when the victim is incapacitated (sexual abuse); had the sexual contact been a sexual act, it would have been punishable as sexual abuse or aggravated sexual abuse (abusive sexual contact); or the offense is a federal sex offense, including an offense subject to a mandatory minimum sentence, committed against a minor by an offender with a prior state or federal conviction for a sex offense committed against a minor (repeated sexual offense). 18 U.S.C. Qualifying prior convictions may include convictions under either state or federal law. Transporting

A 5-year mandatory term of imprisonment must be imposed on "[a]ny person who - (1) knowingly mails, or transports or ships using any means or facility of interstate or foreign commerce or in or affecting interstate or foreign commerce by any means, including by computer, any child pornography." It requires a fine and a minimum term of 15 years for recidivists. 117 (relating to sex offenses involving travel).
Sex offenses are usually state crimes. Federal law, however, outlaws sex offenses when they occur on federal lands or in federal prisons, when they involve interstate or foreign travel, or when they involve child pornography whose production or distribution is associated in some way with interstate or foreign commerce. Mandatory minimum terms of imprisonment attend conviction for any of several of these federal sex crimes.
The most severe mandatory minimum sentences have been reserved for aggravated sexual assaults committed in federal enclaves or federal prisons, for sex offenses resulting in death, and for sex crimes committed against children by repeat offenders.
Two-thirds of the federal trial judges responding to a U.S. Sentencing Commission survey questioned the severity of the mandatory minimum penalties required for receipt of child pornography (5 years; 15 years for repeat offenders). The Commission's report suggested that the perception may lead to inconsistent sentencing in child pornography cases. It explained that more study would be required before it could make any specific recommendations concerning mandatory minimum sentencing in sex offenses.
The constitutional authority to enact federal sex offense punishable by mandatory minimum terms of imprisonment is not unlimited. The ex post facto and double jeopardy clauses; the Fifth Amendment's equal protection component; the Eighth Amendment's cruel and unusual punishment clause; the separation of powers and the reservation of powers principles—all establish boundaries that must be honored. Nevertheless, few defendants have successfully challenged the constitutionality of a mandatory minimum term of imprisonment imposed following their conviction for a federal sex offense.
This report is available in an abridged version as CRS Report R42387, Mandatory Minimum Sentencing for Federal Sex Offenses: An Abridged Overview, without the footnotes or citations to authority found here.