I blogged about this question in January, when the Fourth Circuit held unconstitutional 18 U.S.C. § 4248, which "authorizes the federal government to civilly commit, in a federal facility, any 'sexually dangerous' person 'in the custody' of the Bureau of Prisons — even after that person has completed his entire prison sentence." The Eighth Circuit has now reached the opposite result, and a circuit split on the constitutionality of a federal statute is almost certain to lead to Supreme Court review. (Note that the Fourth Circuit refused to grant rehearing en banc, and a cert petition in the Fourth Circuit case has already been filed.)
Here's an excerpt from the Eighth Circuit's reasoning, which generally strikes me as correct:
Congress has determined that providing for the civil commitment of persons in a variety of circumstances is necessary and proper to the functioning of federal criminal laws. 18 U.S.C. § 4241 authorizes the civil commitment of a defendant "suffering from a mental disease or defect rendering him ... unable to understand the nature and consequences of the proceedings against him or to assist properly in his defense." 18 U.S.C. § 4243 provides for the civil commitment of persons found not guilty by reason of insanity. In appropriate cases 18 U.S.C. § 4244 authorizes the civil commitment, in lieu of imprisonment, of a person found guilty for the maximum period allowed for the offense committed. 18 U.S.C. § 4245 allows the government to seek the temporary civil commitment of a federal prisoner suffering from a mental disease or defect requiring hospitalization. The civil commitment of a hospitalized person whose term of incarceration is about to expire, who has been previously committed under § 4241, or against whom all charges have been dismissed by virtue of insanity, and who "suffer[s] from a mental disease or defect as a result of which his release would create a substantial risk of bodily injury to another person or serious damage to property of another" is authorized by 18 U.S.C. § 4246.
The nexus between these statutes and the enforcement of duly authorized federal criminal laws is evident. In each case the operation of the underlying federal criminal law would be frustrated without the related civil commitment provision. Otherwise, the power to prosecute or punish could be defeated, or the opportunity to prevent a federal crime could be lost, see United States v. Perry, 788 F.2d 100, 111 (3d Cir. 1986) ("[B]ecause Congress has the power to proscribe the activities in question, it has the auxiliary authority, under the necessary and proper clause, to resort to civil commitment to prevent their occurrence."). We reach a similar conclusion with regard to § 4248.
Tom, like the petitioner in Greenwood, is alleged to suffer from a severe mental condition rendering him a menace to members of the general public, including children. Moreover, like the petitioner in Greenwood, federal power over Tom has not yet been exhausted for he was sentenced to a 60 month term of supervised release which had yet to begin at the time he was certified as a sexually dangerous person. See 18 U.S.C. § 3583 ("The Court, in imposing a sentence to a term of imprisonment for a felony or a misdemeanor, may include as a part of the sentence a requirement that the defendant be placed on a term of supervised release after imprisonment ...."). As § 3583 makes clear, the federal government retains a vast amount of power over criminal defendants subject to a term of supervised release that is not dissimilar from the power to prosecute. For example, the court may require the defendant to participate in a rehabilitation program, comply with the requirements of SORNA, and submit to periodic drug testing. § 3583(d). The defendant may be required to submit his person and property to warrantless search. § 3583(d)(3). The court may modify or extend a term of supervised release. § 3583(e)(1)-(4). Of most significance, the court may revoke the term of supervised release altogether and require the defendant to complete it in prison. § 3583(e)(3). In such a case the defendant could be subject to a new term of supervised release following the completion of his prison term. § 3583(h).
Accordingly, we conclude that Congress, having been empowered by the Commerce Clause to criminalize and punish the conduct of which Tom is guilty, has the ancillary authority under the Necessary and Proper Clause to provide for his civil commitment so that he may be prevented from its commission in the first place. As we explained in Greenwood,
The national government has the undoubted right to define federal crimes; to provide for the administration and enforcement of its criminal laws; to prescribe the penalties which will be incurred by those violating them; to furnish institutions where such violators can be confined; and generally to do whatever reasonably and lawfully can be done to protect society against such offenders. We have no doubt that as a necessary incident to the power to provide for the enforcement of the criminal laws of the United States, Congress had the power to enact the legislation in suit providing means for the commitment to the custody of the Attorney General of insane or mentally incompetent persons ....
It is true that ... individuals committed under [the statute] might be prevented from committing state crimes in addition to federal crimes. This does not, however, render the legislation constitutionally defective. First, the Supreme Court "ha[s] never required Congress to legislate with scientific exactitude." Second, even were "exactitude" required, the Adam Walsh Act civil commitment provision applies to a restricted universe of individuals -– those who have been charged with or convicted of a federal crime, see § 4248(a), and "have serious difficulty in refraining from sexually violent conduct or child molestation," see § 4247(a)(6) — who because of the nature of their proclivities are likely to commit federal crimes.
A propensity to engage in sexually violent conduct or child molestation can hardly be disassociated from the likelihood that a person may commit other types of sex related crimes that fall within federal jurisdiction, such as those involving internet child pornography, see 18 U.S.C. § 2252, or the use of the internet to solicit sexual activity from a minor, see 18 U.S.C. § 2422(b). As a Senate report indicates, by one estimate more than 50% of child molesters possessed child pornography at the time of arrest....
While we are mindful of the fact that "Congress, unlike the legislatures of the states, cannot sanction for the general welfare," § 4248 appears to be "aimed at preventing the specific harm to the community proscribed by the [federal sex crime] statutes."