Under
Kansas's
Sexually Violent Predator Act (Act), any person who has a "mental abnormality" or "
personality disorder" and so is likely to engage in "predatory acts of
sexual violence" may be indefinitely confined. Leroy Hendricks and Tim Quinn had extensive histories of
sexually abusing children. When they were due to be released from prison, Kansas filed a petition under the Act in state court to involuntarily commit Hendricks and Quinn. Hendricks and Quinn challenged the
constitutionality of the Act and requested a trial by
jury, which the court granted. Hendricks and Quinn testified during the trial that they agreed with the diagnosis by the state
psychiatrist that they suffer from
pedophilia and admitted that they continued to experience uncontrollable sexual desires for children when under extreme stress. The jury decided that they qualified as sexually violent predators. Since pedophilia is defined as a mental abnormality under the Act, the court ordered that Hendricks be civilly committed. Hendricks appealed the validity of his commitment to the
Kansas Supreme Court and claimed that the state was unconstitutionally using
ex post facto and
double jeopardy law . The state court ruled that the Act was invalid on the grounds that the condition of "mental abnormality" did not satisfy the "
substantive"
due process requirement that
involuntary civil commitment must be based on the finding of the presence of a "
mental illness." It did not address the claims of
ex post facto and of double jeopardy. The
United States Supreme Court granted Kansas
certiorari. ==Decision==