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                       SUPREME COURT OF THE UNITED STATES

                                    --------
                            Nos. 95-1649 AND 95-9075
                                    --------
                               KANSAS, PETITIONER
     95-1649                           v.
                                       __
     LEROY HENDRICKS

     LEROY HENDRICKS, PETITIONER
     95-9075                           v.
                                       __
                                     KANSAS

                   ON WRITS OF CERTIORARI TO THE SUPREME COURT
                                    OF KANSAS

                                 [June 23, 1997]

  JUSTICE THOMAS delivered the opinion of the Court.

  In 1994, Kansas  enacted the Sexually Violent  Predator Act, which establishes
procedures  for   the  civil  commitment  of  persons  who,  due  to  a  "mental
abnormality" or  a "personality  disorder," are likely  to engage  in "predatory
acts of sexual violence."  Kan. Stat.  Ann. S59-29a01 et seq. (1994).  The State
                                                      ______
invoked the Act for the first time to commit Leroy  Hendricks, an inmate who had
a long history of sexually molesting children, and who was scheduled for release
from prison shortly  after the Act became law.  Hendricks challenged his commit-
ment on,  inter alia,  "substantive" due process,  double jeopardy, and  ex post
          ___________                                                    _______
facto grounds.  The  Kansas Supreme Court invalidated the Act,  holding that its
_____
pre-commitment  condition of  a "mental  abnormality" did  not satisfy  what the
court perceived to be the "substantive" due process requirement that involuntary
civil commitment must be

                           95-1649 & 95-9075 - OPINION

2                              KANSAS v. HENDRICKS
                                      __

predicated on  a finding of  "mental illness."  In  re Hendricks, 259  Kan. 246,
                                                ________________
261, 912 P. 2d 129, 138 (1996).  The  State of Kansas petitioned for certiorari.
Hendricks subsequently filed a cross-petition in which he reasserted his federal
double  jeopardy and ex  post facto claims.   We granted certiorari  on both the
                     ______________
petition  and  the cross-petition,  518 U.  S. __  (1996),  and now  reverse the
judgment below.
                                        I
                                        A
  The Kansas Legislature enacted the Sexually Violent Predator Act (Act) in 1994
to   grapple    with   the   problem   of   managing   repeat   sexual   offend-
ers. (Ftnote. 1)    Although  Kansas  already   had  a  statute  addressing  the
     (Ftnote. 1)
involuntary  commitment  of those  defined  as "mentally  ill,"  the legislature
determined that existing civil commitment procedures were inadequate to confront
the risks presented by "sexually violent predators."  In the Act's preamble, the
legislature explained: 

   "[A]  small but extremely dangerous group of sexually violent predators exist
   who do not have a mental disease or  defect that renders them appropriate for
   involuntary treatment pursuant to  the [general involuntary civil  commitment
   statute] . . . .   In contrast  to persons appropriate  for civil  commitment
   under the  [general involuntary civil  commitment statute], sexually  violent
   predators generally have anti-social  personality features which are  unamen-
   able to  existing  mental illness  treatment  modalities and  those  features
   render them likely to engage in

                    
____________________

   1)  Subsequent to Hendricks' commitment, the Kansas Legislature amended the
   1)  
Act in ways not relevant to this case.  See, e.g., Kan. Stat. Ann. S59-29a03
                                             _____
(Supp. 1996) (changing notification period from 60 to 90 days); S59-29a04 (Supp.
1996) (requiring state attorney general to initiate commitment proceedings). 

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                             3
                                      __

   sexually  violent behavior.    The legislature  further  finds that  sexually
   violent  predators' likelihood of engaging in repeat acts of predatory sexual
   violence is high.   The  existing involuntary commitment  procedure . . .  is
   inadequate  to  address the  risk these  sexually  violent predators  pose to
   society.  The legislature further finds that the prognosis for rehabilitating
   sexually violent predators  in a prison setting is poor,  the treatment needs
   of this population  are very long term and the  treatment modalities for this
   population are very  different than the traditional treatment  modalities for
   people  appropriate  for  commitment  under the  [general  involuntary  civil
   commitment statute]."  Kan. Stat. Ann. S59-29a01 (1994).

  As a result, the Legislature found it necessary to  establish "a civil commit-
ment procedure  for the long-term  care and  treatment of  the sexually  violent
predator."  Ibid.  The Act defined a "sexually violent predator" as: 
            _____

   "any person  who has  been convicted  of or charged  with a  sexually violent
   offense and who  suffers from  a mental abnormality  or personality  disorder
   which  makes the  person likely  to engage  in the  predatory acts  of sexual
   violence."  S59-29a02(a).  

A  "mental abnormality"  was defined,  in  turn, as  a  "congenital or  acquired
condition affecting the emotional  or volitional capacity which predisposes  the
person to commit sexually violent offenses in  a degree constituting such person
a menace to the health and safety of others."  S59-29a02(b).  
  As originally structured, the Act's civil commitment  procedures pertained to:
(1) a  presently confined person who,  like Hendricks, "has been  convicted of a
sexually violent offense"  and is scheduled  for release; (2)  a person who  has
been "charged with a sexually violent offense"

                           95-1649 & 95-9075 - OPINION

4                              KANSAS v. HENDRICKS
                                      __

but has  been found incompetent to stand trial; (3)  a person who has been found
"not guilty  by reason  of insanity of  a sexually  violent offense"; and  (4) a
person  found "not  guilty" of a  sexually violent  offense because  of a mental
disease or defect.  S 59-29a03(a), S22-3221 (1995). 
  The initial version of the Act, as applied to a currently confined person such
as Hendricks, was  designed to initiate  a specific series  of procedures.   The
custodial agency was required to notify  the local prosecutor 60 days before the
anticipated  release  of  a  person  who  might  have  met  the Act's  criteria.
S59-29a03.  The prosecutor was then obligated, within 45 days, to decide whether
to file a petition in state  court seeking the person's involuntary  commitment.
S59-29a04.   If such a  petition were filed, the  court was to determine whether
"probable cause"  existed to support a  finding that the person  was a "sexually
violent predator"  and thus eligible for  civil commitment.  Upon  such a deter-
mination,  transfer  of the  individual to  a  secure facility  for professional
evaluation would occur.   S59-29a05.   After that evaluation,  a trial would  be
held  to  determine  beyond a  reasonable  doubt  whether the  individual  was a
sexually violent  predator.  If that  determination were made, the  person would
then be transferred to the custody of the Secretary of Social and Rehabilitation
Services (Secretary) for  "control, care and  treatment until such  time as  the
person's  mental abnormality  or personality  disorder has  so changed  that the
person is safe to be at large."  S59-29a07(a).
  In addition to  placing the burden of  proof upon the State,  the Act afforded
the  individual a  number of  other procedural safeguards.   In  the case  of an
indigent  person, the  State  was required  to provide,  at public  expense, the
assistance  of counsel and an  examination by mental  health care professionals.
S59-29a06.  The individual also received the right to present and cross-

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                             5
                                      __

examine witnesses, and the opportunity  to review documentary evidence presented
by the State.  S59-29a07.
  Once  an individual  was confined,  the Act  required that  "[t]he involuntary
detention or commitment . . .  shall conform to constitutional requirements  for
care and treatment."  S59-29a09.  Confined persons were afforded three different
avenues  of review:  First, the  committing court  was obligated  to conduct  an
annual  review   to  determine   whether  continued  detention   was  warranted.
S59-29a08.  Second, the Secretary was permitted, at any time, to decide that the
confined individual's condition had so changed that release was appropriate, and
could then authorize  the person to petition for release.   S59-29a10.  Finally,
even without the  Secretary's permission, the confined person could  at any time
file a release petition.  S59-29a11.  If the court found that the State could no
longer  satisfy its burden under the initial commitment standard, the individual
would be freed from confinement.  
                                        B
  In 1984,  Hendricks  was convicted  of taking  "indecent liberties"  with  two
13-year-old boys.   After serving nearly 10 years of his sentence, he was slated
for release to a  halfway house.  Shortly before his scheduled release, however,
the State filed  a petition in state court seeking  Hendricks' civil confinement
as a sexually violent predator.   On August 19, 1994, Hendricks  appeared before
the court with counsel and moved to dismiss the petition on the grounds that the
Act  violated various  federal  constitutional provisions.   Although  the court
reserved  ruling on  the Act's  constitutionality, it  concluded that  there was
probable  cause to  support  a finding  that Hendricks  was  a sexually  violent
predator,  and  therefore ordered  that  he  be evaluated  at  the  Larned State
Security Hospital.  

                           95-1649 & 95-9075 - OPINION

6                              KANSAS v. HENDRICKS
                                      __

  Hendricks  subsequently  requested  a  jury  trial  to  determine  whether  he
qualified as  a sexually violent  predator.  During  that trial,  Hendricks' own
testimony revealed a chilling  history of repeated child sexual  molestation and
abuse, beginning in  1955 when he exposed his  genitals to two young girls.   At
that  time, he  pleaded guilty  to indecent  exposure.   Then,  in 1957,  he was
convicted of lewdness involving a young girl and received a brief jail sentence.
In 1960, he  molested two  young boys  while he worked  for a  carnival.   After
serving  two  years in  prison  for that  offense, he  was  paroled, only  to be
rearrested for molesting a 7-year-old girl.  Attempts were made to treat him for
his sexual deviance, and  in 1965 he was considered  "safe to be at  large," and
was discharged from a state psychiatric hospital.  App. 139-144.
  Shortly thereafter,  however, Hendricks  sexually assaulted  another young boy
and girl - he performed oral sex on the 8-year-old girl and fondled the 11-year-
old boy.  He was again imprisoned in  1967, but refused to participate in a  sex
offender treatment program, and  thus remained incarcerated until his  parole in
1972.  Diagnosed  as a pedophile, Hendricks entered into,  but then abandoned, a
treatment  program.  He testified that despite having received professional help
for his pedophilia, he continued to harbor sexual desires for children.  Indeed,
soon after  his 1972 parole, Hendricks  began to abuse his  own stepdaughter and
stepson.   He forced the children to  engage in sexual activity  with him over a
period  of  approximately four  years.    Then, as  noted  above, Hendricks  was
convicted  of  "taking indecent  liberties" with  two  adolescent boys  after he
attempted  to fondle them.   As a result  of that conviction,  he was once again
imprisoned,  and was  serving  that sentence  when  he reached  his  conditional
release date in September 1994.  
  Hendricks admitted that he had repeatedly abused

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                             7
                                      __

children  whenever he  was not  confined.   He  explained that  when he  "get[s]
stressed  out,"  he "can't  control the  urge" to  molest  children.   Id., 172.
                                                                       ___
Although Hendricks recognized that his behavior harms children, and he hoped  he
would not sexually molest children  again, he stated that  the only sure way  he
could keep from sexually  abusing children in the future was "to  die."  Id., at
                                                                         ___
190.   Hendricks readily  agreed with  the state  physician's diagnosis  that he
suffers from  pedophilia and that he is  not cured of the  condition; indeed, he
told  the   physician  that  "treatment  is  bull  -     -  ."    Id.,  at  153,
                                                                  ___
190. (Ftnote. 2)     The jury  unanimously found beyond a  reasonable doubt that
     (Ftnote. 2)
Hendricks  was  a  sexually  violent  predator.  The  trial  court  subsequently
determined,  as a matter  of state law,  that pedophilia qualifies  as a "mental
abnormality" as defined by the Act, and thus ordered Hendricks  committed to the
Secretary's custody. 
  Hendricks appealed, claiming, among other things, that application of the  Act
to him violated the Federal Constitution's Due Process, Double Jeopardy, and Ex 
                                                                             ___

                    
____________________

   2)  In addition to Hendricks' own testimony, the jury heard from Hendricks'
   2)  
stepdaughter and stepson, who recounted the events surrounding their repeated
sexual abuse at Hendricks' hands.  App. 194-212.  One of the girls to whom
Hendricks exposed himself in 1955 testified as well.  Id., at 191-194.  The
                                                      ____
State also presented testimony from Lester Lee, a licensed clinical social
worker who specialized in treating male sexual offenders, and Dr. Charles
Befort, the chief psychologist at Larned State Hospital.  Lee testified that
Hendricks had a diagnosis of personality trait disturbance, passive-aggressive
personality, and pedophilia.  Id., at 219-220.  Dr. Befort testified that
                              ____
Hendricks suffered from pedophilia and is likely to commit sexual offenses
against children in the future if not confined.  Id., at 247-248.  He further
                                                 ___
opined that pedophilia qualifies as a "mental abnormality" within the Act's
definition of that term.  Id., at 263-264.  Finally, Hendricks offered testimony
                          ____
from Dr. William S. Logan, a forensic psychiatrist, who stated that it was not
possible to predict with any degree of accuracy the future dangerousness of a
sex offender.  Id., at 328-331.
               ____

                           95-1649 & 95-9075 - OPINION

8                              KANSAS v. HENDRICKS
                                      __

Post Facto Clauses.   The Kansas Supreme  Court accepted Hendricks' due  process
__________
claim.   In  re Hendricks,  259 Kan.,  at 261,  912 P.  2d, at  138.   The court
         ________________
declared that in order to commit a person involuntarily in a civil proceeding, a
State is required by "substantive" due  process to prove by clear and convincing
evidence that the person  is both (1) mentally ill, and (2)  a danger to himself
or to others.   Id., at 259, 912 P. 2d, at  137.  The court then determined that
                ___
the Act's definition of "mental  abnormality" did not satisfy what it  perceived
to be this Court's "mental illness" requirement in the civil commitment context.
As a  result, the court held  that "the Act violates  Hendricks' substantive due
process rights."  Id., at 261, 912 P. 2d, at 138.
                  ___
  The  majority did  not address  Hendricks'  ex post  facto or  double jeopardy
                                              ______________
claims.   The dissent,  however,  considered each  of Hendricks'  constitutional
arguments and rejected them.   Id., at 264-294, 912 P. 2d, 140-156  (Larson, J.,
                               ____
dissenting).  
                                       II
                                        A
  Kansas  argues that  the Act's  definition of  "mental  abnormality" satisfies
"substantive"  due process  requirements.   We  agree.   Although  freedom  from
physical restraint "has always been at the core of the liberty protected by  the
Due Process Clause from arbitrary governmental action," Foucha v. Louisiana, 504
                                                        ______    __________
U. S. 71,  80 (1992), that  liberty interest  is not  absolute.   The Court  has
recognized that  an individual's constitutionally protected interest in avoiding
physical restraint may be overridden even in the civil context: 

   "[T]he liberty secured  by the  Constitution of  the United  States to  every
   person within  its jurisdiction does  not import  an absolute  right in  each
   person to be,  at all times  and in all  circumstances, wholly free  from re-
   straint. There are manifold restraints to

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                             9
                                      __

   which every person is necessarily subject for  the common good.  On any other
   basis organized  society could not exist with safety to its members."  Jacob-
                                                                          ______
   son v. Massachusetts, 197 U. S. 11, 26 (1905).
   ___    ______________

Accordingly,  States  have in  certain  narrow  circumstances provided  for  the
forcible civil detainment of people who are unable to control their behavior and
who thereby pose  a danger to the public health and  safety.  See, e.g., 1788 N.
                                                                   ____
Y. Laws,  ch. 31 (Feb. 9, 1788) (permitting confinement of the "furiously mad");
see  also A.  Deutsch, The Mentally  Ill in  America (1949)  (tracing history of
civil commitment in the 18th and  19th centuries); G. Grob, Mental  Institutions
in America: Social Policy to 1875 (1973) (discussing colonial and early American
civil  commitment statutes).    We  have  consistently upheld  such  involuntary
commitment statutes  provided the  confinement takes  place  pursuant to  proper
procedures and evidentiary standards.   See Foucha,  supra, at 80; Addington  v.
                                            _______  _____         _________
Texas,  441  U.  S. 418,  426-427  (1979).   It  thus  cannot be  said  that the
______
involuntary  civil confinement  of a  limited subclass  of dangerous  persons is
contrary to our understanding of ordered liberty.  Cf.  id., at 426.  
                                                        ___
  The challenged Act unambiguously requires a finding of dangerousness either to
one's   self  or  to  others  as  a  prerequisite  to  involuntary  confinement.
Commitment proceedings can be  initiated only when a person  "has been convicted
of  or charged  with a  sexually violent  offense," and  "suffers from  a mental
abnormality or personality  disorder which makes the person likely  to engage in
the predatory acts  of sexual violence."   Kan. Stat. Ann. S59-29a02(a)  (1994).
The statute thus requires proof of more than a mere  predisposition to violence;
rather,  it requires evidence  of past sexually  violent behavior and  a present
mental condition  that creates a likelihood of such conduct in the future if the
person is not incapacitated.  As we have recognized, 

                           95-1649 & 95-9075 - OPINION

10                             KANSAS v. HENDRICKS
                                      __

"[p]revious instances of violent  behavior are an important indicator  of future
violent tendencies."  Heller v. Doe, 509 U. S.  312, 323 (1993); see also Schall
                      ______    ____                                      ______
v. Martin,  467 U. S. 253, 278  (1984) (explaining that  "from a legal  point of
   _______
view  there  is nothing  inherently unattainable  about  a prediction  of future
criminal conduct").  A finding  of dangerousness, standing alone,  is ordinarily
not a sufficient ground upon which to justify indefinite involuntary commitment.
We  have sustained civil  commitment statutes  when they  have coupled  proof of
dangerousness  with  the proof  of  some additional  factor,  such as  a "mental
illness" or "mental abnormality."   See, e.g., Heller, supra,  314-315 (Kentucky
                                         _____ _______ _____
statute  permitting commitment  of  "mentally retarded"  or  "mentally ill"  and
dangerous  individual); Allen v. Illinois,  478 U. S. 364,  366 (1986) (Illinois
                        _____    _________
statute  permitting  commitment of  "mentally  ill"  and dangerous  individual);
Minnesota ex  rel. Pearson  v. Probate  Court of  Ramsey  Cty., 309  U. S.  270,
__________________________     ________________________________
271-272 (1940) (Minnesota statute  permitting commitment of dangerous individual
with "psychopathic personality").   These added statutory requirements  serve to
limit  involuntary civil  confinement  to those  who  suffer from  a  volitional
impairment rendering  them dangerous beyond  their control.   The Kansas  Act is
plainly  of a  kind with these  other civil  commitment statutes:  It requires a
finding of future dangerousness, and then links that finding to the existence of
a "mental abnormality" or "personality disorder" that makes it difficult, if not
impossible,  for the person to control his  dangerous behavior.  Kan. Stat. Ann.
S59-29a02(b) (1994).  The precommitment requirement of a "mental abnormality" or
"personality  disorder"  is consistent  with  the  requirements of  these  other
statutes  that we have upheld  in that it narrows  the class of persons eligible
for confinement to those who are unable to control their dangerousness.  
  Hendricks nonetheless argues that our earlier cases

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                            11
                                      __

dictate a finding  of "mental illness" as  a prerequisite for civil  commitment,
citing Foucha,  and Addington.  He  then asserts that a  "mental abnormality" is
       _______      _________
not equivalent to  a "mental illness" because it is a  term coined by the Kansas
___
Legislature, rather than by  the psychiatric community.  Contrary  to Hendricks'
assertion, the term "mental  illness" is devoid of any  talismanic significance.
Not  only do "psychiatrists disagree  widely and frequently  on what constitutes
mental illness," Ake v. Oklahoma, 470 U. S. 68, 81 (1985), but  the Court itself
                 ___    _________
has used  a variety of  expressions to  describe the mental  condition of  those
properly  subject to  civil confinement.   See, e.g.,  Addington, 441  U. S., at
                                                _____  _________
425-426 (using the  terms "emotionally disturbed" and  "mentally ill"); Jackson,
                                                                        ________
406 U. S.,  at 732,  737 (using  the terms  "incompetency" and  "insanity"); cf.
Foucha, 504  U. S., at  88 (O'CONNOR, J.,  concurring in part and  concurring in
______
judgment)  (acknowledging State's  authority to  commit a  person when  there is
"some medical justification for doing so"). 
  Indeed,  we have  never required  State legislatures  to adopt  any particular
nomenclature  in drafting civil commitment statutes.  Rather, we have tradition-
ally  left to legislators  the task of  defining terms of a  medical nature that
have legal significance.   Cf. Jones v. United States, 463 U. S. 354, 365, n. 13
                               _____    ______________
(1983).  As  a consequence, the States have, over  the years, developed numerous
specialized terms to define mental health concepts.  Often, those definitions do
not  fit precisely with the definitions employed  by the medical community.  The
legal   definitions  of   "insanity"   and  "competency,"   for  example,   vary
substantially  from their  psychiatric  counterparts.   See,  e.g., Gerard,  The
                                                              _____
Usefulness of the  Medical Model to the  Legal System, 39  Rutgers L. Rev.  377,
391-394  (1987) (discussing differing purposes  of legal system  and the medical
profession  in recognizing mental  illness).  Legal  definitions, however, which
must  "take into account such issues as individual responsi-

                           95-1649 & 95-9075 - OPINION

12                             KANSAS v. HENDRICKS
                                      __

bility . . . and  competency," need  not mirror  those advanced  by the  medical
profession.  American Psychiatric Association, Diagnostic and Statistical Manual
of Mental Disorders xxiii, xxvii (4th ed. 1994).
  To the extent that the  civil commitment statutes we have considered set forth
criteria relating to an individual's inability to control his dangerousness, the
Kansas Act sets  forth comparable  criteria and  Hendricks' condition  doubtless
satisfies  those  criteria.    The  mental  health  professionals who  evaluated
Hendricks  diagnosed him as suffering from pedophilia, a condition the psychiat-
ric profession itself classifies as a serious mental disorder.   See, e.g., id.,
                                                                      ____  ___
at 524-525, 527-528;  1 American Psychiatric Association,  Treatments of Psychi-
atric Disorders, 617-633 (1989); Abel & Rouleau, Male Sex Offenders, in Handbook
of Outpatient Treatment of Adults 271 (M. Thase, B. Edelstein, & M. Hersen, eds.
1990). (Ftnote. 3)   Hendricks even  conceded that,  when  he becomes  "stressed
       (Ftnote. 3)
out," he cannot "control the urge" to molest children.  App. 172.  This admitted
lack of volitional control,  coupled with a prediction of  future dangerousness,
adequately distinguishes Hendricks from other dangerous persons who  are perhaps
more properly dealt

                    
____________________

   3)  We recognize, of course, that psychiatric professionals are not in
   3)  
complete harmony in casting pedophilia, or paraphilias in general, as "mental
illnesses."  Compare Brief for American Psychiatric Association as Amicus Curiae
26 with Brief for Menninger Foundation et al. as Amici Curiae 22-25.  These
                                                 ____________
disagreements, however, do not tie the State's hands in setting the bounds of
its civil commitment laws.  In fact, it is precisely where such disagreement
exists that legislatures have been afforded the widest latitude in drafting such
statutes.  Cf. Jones v. United States, 463 U. S. 354, 365, n. 13 (1983).  As we
               _____    ______________
have explained regarding congressional enactments, when a legislature "under-
takes to act in areas fraught with medical and scientific uncertainties,
legislative options must be especially broad and courts should be cautious not
to rewrite legislation."  Id., at 370 (internal quotation marks and citation
                          ___
omitted).  

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                            13
                                      __

with  exclusively through criminal proceedings.  Hendricks' diagnosis as a pedo-
phile, which  qualifies as a  "mental abnormality" under  the Act,  thus plainly
suffices for due process purposes.
                                        B
  We granted Hendricks' cross-petition to determine whether the Act violates the
Constitution's double jeopardy prohibition or  its ban on ex post  facto lawmak-
                                                          ______________
ing.   The thrust of  Hendricks' argument is  that the Act  establishes criminal
proceedings; hence confinement under it necessarily constitutes  punishment.  He
contends that where, as here, newly enacted "punishment" is predicated upon past
conduct for  which he has  already been convicted and  forced to serve  a prison
sentence, the Constitution's  Double  Jeopardy  and Ex  Post  Facto Clauses  are
                                                    _______________
violated.  We are unpersuaded by Hendricks' argument that Kansas has established
criminal proceedings.
  The categorization of a  particular proceeding as civil  or criminal "is first
of all a  question of statutory construction."   Allen, 478  U. S., at 368.   We
                                                 ______
must  initially ascertain whether the legislature meant the statute to establish
"civil"  proceedings.   If so, we  ordinarily defer to  the legislature's stated
intent.  Here, Kansas'  objective to create a  civil proceeding is evidenced  by
its placement  of the Sexually  Violent Predator  Act within the  Kansas probate
code, instead  of the criminal code,  as well as  its description of the  Act as
creating a "civil commitment  procedure."  Kan. Stat.  Ann.,  Article 29  (1994)
            ___________________________
("Care and  Treatment for Mentally  Ill Persons"),  S59-29a01 (emphasis  added).
Nothing  on the  face of  the statute  suggests that  the legislature  sought to
create anything  other than a  civil commitment  scheme designed to  protect the
public from harm.
  Although we recognize that a "civil label is not always

                           95-1649 & 95-9075 - OPINION

14                             KANSAS v. HENDRICKS
                                      __

dispositive,"  Allen, supra, at 369,  we will reject  the legislature's manifest
               ______ _____
intent only where a party challenging the statute provides  "the clearest proof"
that "the statutory scheme  [is] so punitive either  in purpose or effect as  to
negate [the State's] intention" to deem it "civil."   United States v. Ward, 448
                                                      _____________    _____
U. S. 242, 248-249 (1980).  In those limited circumstances, we will consider the
statute to  have established  criminal proceedings for  constitutional purposes.
Hendricks, however, has failed to satisfy this heavy burden.
  As a threshold matter,  commitment under the Act does not implicate  either of
the two  primary objectives  of criminal punishment: retribution  or deterrence.
The Act's purpose  is not retributive because it does  not affix culpability for
prior criminal  conduct.  Instead, such  conduct is used solely  for evidentiary
purposes, either to demonstrate that a "mental abnormality" exists or to support
a  finding of  future  dangerousness.   We  have  previously concluded  that  an
Illinois statute was nonpunitive even though it was triggered by the  commission
of a sexual assault, explaining that evidence of the prior  criminal conduct was
"received  not to  punish past  misdeeds, but  primarily to  show  the accused's
mental  condition and to  predict future behavior."   Allen, supra, at  371.  In
                                                      _____  _____
addition, the Kansas Act does not make a criminal conviction  a prerequisite for
commitment  - persons  absolved of  criminal responsibility  may nonetheless  be
subject to  confinement under the Act.  See Kan. Stat. Ann. S59-29a03(a) (1994).
An absence of the necessary criminal  responsibility suggests that the State  is
not seeking retribution for a past misdeed.  Thus, the fact that the Act  may be
"tied  to criminal activity" is "insufficient to render the statut[e] punitive."
United States v. Ursery, 518 U. S. __ (1996) (slip op., at 24).  
_____________    _______
  Moreover,  unlike a  criminal statute, no finding  of scienter  is required to
commit an individual who is

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                               KANSAS v. HENDRICKS                            15
                                      __

found to be a  sexually violent predator; instead, the  commitment determination
is made based on a "mental abnormality" or "personality disorder" rather than on
one's criminal intent.   The existence of a  scienter requirement is customarily
an  important element  in  distinguishing criminal  from  civil statutes.    See
Kennedy v. Mendoza-Martinez, 372  U. S. 144, 168 (1963).  The absence  of such a
_______    _________________
requirement here is evidence that confinement  under the statute is not intended
to be retributive.
  Nor can  it be said  that the  legislature intended the  Act to function as  a
deterrent.   Those persons committed under the Act are, by definition, suffering
from a "mental  abnormality" or a "personality disorder" that prevents them from
exercising adequate control  over their  behavior.  Such  persons are  therefore
unlikely to  be deterred  by  the threat  of confinement.    And the  conditions
surrounding that  confinement do not  suggest a punitive purpose  on the State's
part.  The  State has represented that  an individual confined under  the Act is
not subject  to the more restrictive  conditions placed on  state prisoners, but
instead experiences essentially the same conditions as any involuntarily commit-
ted patient in the state mental  institution.  App. 50-56, 59-60.   Because none
of the parties  argues that  people institutionalized under  the Kansas  general
civil  commitment statute are subject  to punitive conditions,  even though they
may be involuntarily confined, it is difficult to conclude that persons confined
under this Act are being "punished."
  Although the civil commitment scheme at issue here does involve an affirmative
restraint, "the mere fact that a person is detained does not inexorably lead  to
the conclusion  that the government  has imposed punishment."   United States v.
                                                                _____________
Salerno, 481 U. S. 739, 746 (1987).  The State may take measures to restrict the
________
freedom of the dangerously mentally ill.  This is a legitimate non-

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16                             KANSAS v. HENDRICKS
                                      __

punitive governmental objective and has been historically so regarded.  Cf. id.,
                                                                            ____
at  747.  The  Court has, in  fact, cited the  confinement of "mentally unstable
individuals who  present a  danger  to the  public" as  one  classic example  of
nonpunitive  detention.   Id., at  748-749.   If  detention for  the purpose  of
                          ____
protecting the community from harm  necessarily constituted punishment, then all
                                    ___________
involuntary civil  commitments would have to  be considered punishment.   But we
have never so held.
  Hendricks  focuses on  his  confinement's potentially  indefinite  duration as
evidence of  the State's punitive  intent.  That  focus, however, is  misplaced.
Far from any punitive objective, the confinement's duration is instead linked to
the stated  purposes of the  commitment, namely,  to hold the  person until  his
mental abnormality no  longer causes him to  be a threat to others.   Cf. Jones,
                                                                          ______
463 U.  S., at  368 (noting  with approval  that  "because it  is impossible  to
predict  how  long it  will  take  for any  given  individual  to recover  [from
insanity] -  or indeed whether he will ever recover  - Congress has chosen . . .
to  leave the length of commitment indeterminate,  subject to periodic review of
the patients's  suitability for release").  If, at any time, the confined person
is  adjudged "safe  to be  at large,"  he is  statutorily entitled  to immediate
release.  Kan. Stat. Ann. S59-29a07 (1994).  
  Furthermore, commitment  under the  Act is only potentially  indefinite.   The
                                                  ___________
maximum  amount of time an individual can  be incapacitated pursuant to a single
judicial proceeding is one  year.  S59-29a08.   If Kansas seeks to  continue the
detention  beyond  that  year,  a  court  must once  again  determine  beyond  a
reasonable doubt that the detainee satisfies the same standards  as required for
the initial confinement.  Ibid.  This requirement again demonstrates that Kansas
                          _____
does not intend an individual  committed pursuant to the Act to  remain confined
any longer than he suffers from a mental

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                               KANSAS v. HENDRICKS                            17
                                      __

abnormality rendering him unable to control his dangerousness.  
  Hendricks  next  contends  that  the  State's  use  of  procedural  safeguards
traditionally  found  in criminal  trials  makes the  proceedings  here criminal
rather  than civil.   In Allen,  we confronted a  similar argument.   There, the
                         _____
petitioner  "place[d] great reliance on the fact  that proceedings under the Act
are  accompanied by procedural safeguards  usually found in  criminal trials" to
argue that the proceedings  were civil in  name only.   478 U. S.,  at 371.   We
rejected  that  argument, however,  explaining  that  the  State's decision  "to
provide  some of the safeguards applicable in criminal trials cannot itself turn
these proceedings  into criminal  prosecutions."   Id., at  372.   The  numerous
                                                   ___
procedural and evidentiary protections afforded here demonstrate that the Kansas
Legislature has taken great care to confine only a narrow  class of particularly
dangerous individuals,  and then  only after  meeting  the strictest  procedural
standards.   That Kansas  chose to afford  such procedural protections  does not
transform a civil commitment proceeding into a criminal prosecution.
  Finally,  Hendricks argues  that the  Act is  necessarily punitive  because it
fails  to offer any legitimate  "treatment."  Without  such treatment, Hendricks
asserts, confinement under the Act amounts to little more than disguised punish-
ment.    Hendricks'  argument  assumes  that  treatment  for  his  condition  is
available, but that the State has failed (or refused) to provide it.  The Kansas
Supreme Court, however, apparently rejected this assumption, explaining:

     "It  is clear that the overriding concern of the legislature is to continue
   the segregation of  sexually violent  offenders from the  public.   Treatment
   with the goal of reintegrating them into society is incidental, at best.  The
   record  reflects that  treatment for  sexually violent  predators is  all but
   nonexistent. 

                           95-1649 & 95-9075 - OPINION

18                             KANSAS v. HENDRICKS
                                      __

   The  legislature concedes that sexually violent predators are not amenable to
   treatment  under [the existing  Kansas involuntary  commitment statute].   If
   there  is nothing  to treat  under [that  statute], then  there is  no mental
   illness.   In  that light,  the provisions  of the  Act for  treatment appear
   somewhat disingenuous."  259 Kan., at 258, 912 P. 2d, at 136.

It is possible to read this passage as a determination that Hendricks' condition
was untreatable under the existing Kansas civil commitment statute, and thus the
    ___________
Act's sole purpose was  incapacitation.  Absent a treatable  mental illness, the
Kansas court concluded, Hendricks could not be detained against his will. 
  Accepting  the Kansas  court's apparent  determination that  treatment  is not
possible  for this  category of individuals  does not  obligate us  to adopt its
legal conclusions.  We have already observed that, under the appropriate circum-
stances  and  when accompanied  by proper  procedures,  incapacitation may  be a
legitimate end of the civil law.  See Allen,  supra, at 373; Salerno, 481 U. S.,
                                      ______  _____          ________
at  748-749.   Accordingly,  the Kansas  court's  determination that  the  Act's
"overriding  concern"  was  the   continued  "segregation  of  sexually  violent
offenders"  is consistent  with our  conclusion that  the Act  establishes civil
proceedings, 259 Kan., at  258, 912 P. 2d, at 136,  especially when that concern
is coupled  with the  State's ancillary  goal  of providing  treatment to  those
offenders, if such  is possible.   While we have  upheld state civil  commitment
statutes that aim both to  incapacitate and to treat, see Allen,  supra, we have
                                                          _____   _____
never held that the  Constitution prevents a State from civilly  detaining those
for whom  no treatment  is  available, but  who nevertheless  pose  a danger  to
others.   A State could  hardly be  seen as furthering  a "punitive" purpose  by
involuntarily confining persons afflicted with an untreatable, highly contagious
disease.  Accord Compagnie Francaise de Navigation a Vapeur v. Louisi-
                 __________________________________________    _______

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                            19
                                      __

ana Bd. of  Health, 186 U. S. 380  (1902) (permitting involuntary quarantine  of
___________________
persons suffering from communicable diseases).  Similarly, it would be of little
value to  require  treatment as  a  precondition for  civil  confinement of  the
dangerously  insane when no acceptable treatment existed.  To conclude otherwise
would obligate a  State to  release certain confined  individuals who were  both
mentally ill and dangerous simply because they could not be successfully treated
for their  afflictions.   Cf. Greenwood  v. United  States, 350  U. S.  366, 375
                              _________     _______________
(1956)  ("The fact that  at present there  may be little  likelihood of recovery
does  not defeat federal power to make  this initial commitment of the petition-
er");  O'Connor  v. Donaldson,  422  U. S.  563,  584  (1975)  (Burger,  C.  J.,
       ________     __________
concurring) ("[I]t remains a stubborn  fact that there are many forms  of mental
illness  which are not understood, some which  are untreatable in the sense that
no effective  therapy has yet been discovered for them, and that rates of `cure'
are generally low").  
  Alternatively, the Kansas Supreme Court's opinion can be read to conclude that
Hendricks'  condition is  treatable,  but that  treatment  was not  the  State's
"overriding concern,"  and that no treatment was being provided (at least at the
time Hendricks was committed).   259 Kan., at 258, 912 P. 2d,  at 136.  See also
ibid.   ("It  is clear  that the  primary objective  of the  Act is  to continue
_____
incarceration  and  not  to  provide  treatment").    Even  if  we  accept  this
determination that the provision  of treatment was not the  Kansas Legislature's
"overriding" or "primary" purpose in passing the Act, this does not rule out the
possibility that an ancillary purpose  of the Act was to provide  treatment, and
it does not  require us to conclude that the Act  is punitive.  Indeed, critical
language  in  the  Act itself  demonstrates  that the  Secretary  of  Social and
Rehabilitation  Services, under  whose  custody sexually  violent predators  are
committed, has an obligation to provide treatment to individuals like

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20                             KANSAS v. HENDRICKS
                                      __

Hendricks.  S59-29a07(a) ("If the court or  jury determines that the person is a
sexually violent predator, the person  shall be committed to the custody  of the
secretary  of social and rehabilitation services for control, care and treatment
                                                     ___________________________
until such time as the  person's mental abnormality or personality  disorder has
so changed that the  person is safe to be at large" (emphasis added)).  Other of
the  Act's  sections echo  this obligation  to  provide treatment  for committed
persons.  See, e.g., S59-29a01 (establishing civil commitment procedure "for the
               ____
long-term care  and  treatment of  the  sexually violent  predator");  S59-29a09
(requiring  the confinement to "conform  to constitutional requirements for care
and treatment").  Thus,  as in Allen, "the State  has a statutory obligation  to
                               _____
provide `care and treatment for  [persons adjudged sexually dangerous]  designed
to  effect recovery,'"  478  U. S.,  at 369  (quoting Ill.  Rev. Stat.,  ch. 38,
(para.) 105-8 (1985)),  and we may therefore conclude that  "the State has . . .
provided for the treatment of those it commits."  478 U. S., at 370.
  Although the treatment  program initially  offered Hendricks  may have  seemed
somewhat meager,  it must be remembered  that he was the  first person committed
under the Act.  That the State did  not have all of its treatment procedures  in
place  is thus not surprising.  What  is significant, however, is that Hendricks
was placed under  the supervision of the Kansas Department  of Health and Social
and Rehabilitative Services, housed in a unit segregated from the general prison
population and operated not by employees  of the Department of Corrections,  but
by other trained individuals. (Ftnote. 4)  And,
                              (Ftnote. 4)

                    
____________________

   4)  We have explained that the States enjoy wide latitude in developing
   4)  
treatment regimens.  Youngberg v. Romeo, 457 U. S. 307, 317 (1982) (observing
                     _________    _____
that the State "has considerable discretion in determining the nature and scope
of its responsibilities").  In Allen, for example, we concluded that "the State
                               _____
serves its purpose of treating rather than punishing sexually dangerous person
by committing them to an institution expressly designed to provide psychiatric
care and treatment."  478 U. S., at 373 (emphasis in original omitted).  By this
measure, Kansas has doubtless satisfied its obligation to provide available
treatment.

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                            21
                                      __

before this Court,  Kansas declared "[a]bsolutely" that  persons committed under
the Act are  now receiving in the neighborhood  of "31.5 hours of  treatment per
week."  Tr. of Oral Arg. 14-15, 16. (Ftnote. 5)  
                                    (Ftnote. 5)
  Where the State has "disavowed any punitive intent"; limited confinement to  a
small segment of particularly  dangerous individuals; provided strict procedural
safeguards; directed that confined persons be segregated from the general prison
population  and  afforded  the  same status  as  others  who  have  been civilly
committed;  recommended treatment if  such is possible;  and permitted immediate
release upon  a showing that the  individual is no longer  dangerous or mentally
impaired, we cannot  say that it acted with punitive intent.   We therefore hold
that  the Act  does  not establish  criminal  proceedings and  that  involuntary
confinement pursuant to the Act is not punitive.  Our conclusion that the Act is
nonpunitive thus  removes an essential  prerequisite for both  Hendricks' double
jeopardy and ex post facto claims.
             _____________

                    
____________________

   5)  Indeed, we have been informed that an August 28, 1995, hearing on
   5)  
Hendricks' petition for state habeas corpus relief, the trial court, over
admittedly conflicting testimony, ruled that: "[T]he allegation that no
treatment is being provided to any of the petitioners or other persons committed
to the program designated as a sexual predator treatment program is not true.  I
find that they are receiving treatment."  App. 453-454.  Thus, to the extent
that treatment is available for Hendricks' condition, the State now appears to
be providing it.  By furnishing such treatment, the Kansas Legislature has
indicated that treatment, if possible, is at least an ancillary goal of the Act,
which easily satisfies any test for determining that the Act is not punitive.

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22                             KANSAS v. HENDRICKS
                                      __

                                        1
  The Double  Jeopardy Clause provides:  "[N]or shall any  person be subject for
the same  offence  to be  twice put  in jeopardy  of  life or  limb."   Although
generally understood to preclude a second prosecution for the  same offense, the
Court has also interpreted this prohibition to prevent the State from "punishing
twice, or attempting a  second time to punish criminally, for the same offense."
Witte  v. United  States,  515 U.  S.  389, 396  (1995)  (emphasis and  internal
_____     ______________
quotation  marks omitted).   Hendricks argues that,  as applied to  him, the Act
violates  double  jeopardy principles  because  his confinement  under  the Act,
imposed  after a  conviction and  a term  of incarceration,  amounted to  both a
second prosecution and a second punishment for the same offense.  We disagree. 
  Because we have  determined that the Kansas Act is civil in nature, initiation
of its  commitment proceedings does  not constitute  a second prosecution.   Cf.
Jones  v.  United States,  463 U. S.  354  (1984) (permitting  involuntary civil
_____      ______________
commitment after verdict  of not guilty  by reason of  insanity).  Moreover,  as
commitment  under the Act is not tantamount to "punishment," Hendricks' involun-
tary  detention does  not violate the  Double Jeopardy Clause,  even though that
confinement may follow a prison term.  Indeed, in Baxstrom v. Herold, 383  U. S.
                                                  ________    _______
107  (1966),  we expressly  recognized that  civil  commitment could  follow the
expiration  of a prison  term without offending double  jeopardy principles.  We
reasoned that "there is  no conceivable basis for distinguishing  the commitment
of  a  person who  is nearing  the  end of  a penal  term  from all  other civil
commitments."    Id.,  at  111-112.    If  an  individual  otherwise  meets  the
                 ___
requirements for involuntary  civil commitment, the State is under no obligation
to release that individual simply because the detention would follow a period of

                           95-1649 & 95-9075 - OPINION

                               KANSAS v. HENDRICKS                            23
                                      __

incarceration.
  Hendricks also argues that even if the Act survives the "multiple punishments"
test, it nevertheless fails  the "same elements"  test of Blockburger v.  United
                                                          ___________     ______
States,  284 U. S.  299  (1932).   Under  Blockburger, "where  the  same act  or
_______                                   ___________
transaction constitutes  a violation of  two distinct statutory  provisions, the
test  to be applied to determine whether there  are two offenses or only one, is
whether each provision requires proof of a fact which the other does not."  Id.,
                                                                            ___
at  304.  The Blockburger  test, however, simply  does not apply  outside of the
              ___________
successive  prosecution context.  A proceeding under  the Act does not define an
"offense," the elements  of which can be compared to the  elements of an offense
for which the  person may previously have been convicted.  Nor does the Act make
the commission of  a specified "offense" the  basis for invoking the  commitment
proceedings.    Instead,  it uses  a  prior  conviction  (or previously  charged
conduct) for evidentiary  purposes to determine whether a  person suffers from a
"mental abnormality"  or "personality disorder" and  also poses a  threat to the
public.  Accordingly, we  are unpersuaded by Hendricks' novel application of the
Blockburger test  and conclude that the Act does not violate the Double Jeopardy
___________
Clause.
                                        2
  Hendricks' ex post facto claim is similarly flawed.  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.
California Dept. of Corrections v. Morales, 514 U. S.  499, 505 (1995)  (quoting
_______________________________    ________
Lindsey  v. Washington,  301  U. S. 397,  401 (1937)).   As  we  have previously
_______     ___________
determined, the Act does  not impose punishment; thus, its application  does not
raise  ex  post  facto  concerns.   Moreover,  the  Act  clearly  does  not have
       _______________
retroactive effect.  Rather, the Act permits involuntary

                           95-1649 & 95-9075 - OPINION

24                             KANSAS v. HENDRICKS
                                      __

confinement  based upon a determination  that the person  currently both suffers
                                                          _________
from a  "mental abnormality" or "personality  disorder" and is likely  to pose a
future  danger to the public.   To the  extent that past behavior  is taken into
account, it is  used, as noted above, solely for  evidentiary purposes.  Because
the Act does  not criminalize  conduct legal before  its enactment, nor  deprive
Hendricks of  any defense that was available  to him at the  time of his crimes,
the Act does not violate the Ex Post Facto Clause. 
                             _____________
                                       III
  We  hold that  the Kansas  Sexually  Violent Predator  Act  comports with  due
process  requirements and neither runs  afoul of double  jeopardy principles nor
constitutes  an exercise in impermissible ex post facto lawmaking.  Accordingly,
                                          _____________
the judgment of the Kansas Supreme Court is reversed.
                                                               It is so ordered.
                                                               _________________