The Ex Post Facto Clause, which forbids the application of any new punitive measure to a crime already consummated, has been interpreted to pertain exclusively to penal statutes.
An inmate was committed as a sexually violent predator after the trial court found that pedophilia was a mental abnormality as defined by the Sexually Violent Predator Act (Act). When the inmate appealed his civil commitment under the Act, the Supreme Court of Kansas invalidated the Act for not satisfying substantive due process requirements. The State appealed the judgment.
Did the Sexually Violent Predator Act satisfy substantive due process?
The court held that the Act satisfied due process requirements because it unambiguously required a finding of dangerousness either to one's self or to others as a prerequisite to involuntary confinement. Commitment proceedings were initiated only when a person had been convicted of or charged with a sexually violent offense and suffered from a mental abnormality or personality disorder that made the person likely to engage in the predatory acts of sexual violence. Kan. Stat. Ann. § 59-29a02(a) (1994). As the Act did not establish criminal proceedings and because the involuntary confinement pursuant to the Act was not punitive, inmate's involuntary detention did not violate the Double Jeopardy Clause, even though the confinement followed a prison term. Because the Act did not impose punishment, did not criminalize conduct legal before its enactment, or deprive inmate of any defense that was available to him at the time of his crimes, the Act was not impermissible under the Ex Post Facto Clause.