Cite as: 564 U. S. ____ (2011)          1

                           Per Curiam

SUPREME COURT OF THE UNITED STATES
         UNITED STATES v. JUVENILE MALE
   ON PETITION FOR WRIT OF CERTIORARI TO THE UNITED 

    STATES COURT OF APPEALS FOR THE NINTH CIRCUIT

              No. 09–940    Decided June 27, 2011


  PER CURIAM.
  The Court of Appeals in this case held that the require
ments of the Sex Offender Registration and Notification
Act (SORNA), 

. §16901 et seq., violate the Ex
Post Facto Clause of the Constitution, Art. I, §9, cl. 3,
when applied to juveniles adjudicated as delinquent before
SORNA’s enactment. We conclude that the Court of Ap
peals had no authority to enter that judgment because it
had no live controversy before it.
                               I
   Respondent Juvenile Male was 13 years old when he
began sexually abusing a 10-year-old boy on the Fort
Belknap Indian Reservation in Montana. The abuse
continued for approximately two years, until respondent
was 15 and his victim 12. In 2005, respondent was
charged in the District of Montana with delinquency
under the Federal Juvenile Delinquency Act, 

.
§5031 et seq. Respondent pleaded “true” to charges that
he knowingly engaged in sexual acts with a child under
12, which would have been a federal crime had respondent
been an adult. See §§2241(c), 1153(a). The court sen
tenced respondent to two years of juvenile detention,
followed by juvenile supervision until his 21st birthday.
Respondent was to spend the first six months of his post
confinement supervision in a prerelease center. See
United States v. Juvenile Male, 560 U. S. ___, ___ (2010)
(per curiam) (slip op., at 1).
   In 2006, while respondent remained in juvenile deten
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tion, Congress enacted SORNA. 120 Stat. 590. Under
SORNA, a sex offender must “register, and keep the re
gistration current, in each jurisdiction” where the offen
der resides, is employed, or attends school. 

.
§16913(a). This registration requirement extends to cer
tain juveniles adjudicated as delinquent for serious sex
offenses. §16911(8). In addition, an interim rule issued by
the Attorney General mandates that SORNA’s require
ments apply retroactively to sex offenders convicted before
the statute’s enactment. 72 Fed. Reg. 8897 (2007) (codi
fied at 28 CFR pt. 72 (2010)); see 

. §16913(d).1
   In July 2007, the District Court determined that re
spondent had failed to comply with the requirements of
his prerelease program. The court revoked respondent’s
juvenile supervision, imposed an additional 6-month term
of detention, and ordered that the detention be followed by
supervision until respondent’s 21st birthday. 560 U. S., at
___ (slip op., at 1–2). At the Government’s urging, and
over respondent’s objection, the court also imposed a
“special conditio[n]” of supervision requiring respondent to
register and keep current as a sex offender. Id., at ___
(slip op., at 2) (internal quotation marks omitted); see Pet.
for Cert. 9 (noting the Government’s argument in the
District Court that respondent should be required to regis
ter under SORNA “ ‘at least until’ ” his release from juve
nile supervision on his 21st birthday).
   On appeal to the Ninth Circuit, respondent challenged
this “special conditio[n]” of supervision. He requested that
the Court of Appeals “reverse th[e] portion of his sentence
——————
  1 On December 29, 2010, the Attorney General finalized the interim

rule. See 75 Fed. Reg. 81849. In Reynolds v. United States, No. 10–
6549, this Court granted certiorari on the question whether sex offend
ers convicted before the enactment of SORNA have standing to chal
lenge the validity of the Attorney General’s interim rule. 562 U. S. ___
(2011); Pet. for Cert. in Reynolds, p. i. Reynolds is slated to be heard
next Term.
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                           Per Curiam

requiring Sex Offender Registration and remand with
instructions that the district court . . . strik[e] Sex Of
fender Registration as a condition of juvenile supervision.”
Opening Brief for Defendant-Appellant in No. 07–30290
(CA9), p. 25. Then, in May 2008, with his appeal still
pending in the Ninth Circuit, respondent turned 21, and
the juvenile-supervision order requiring him to register as
a sex offender expired. 560 U. S., at ___ (slip op., at 2).
  Over a year after respondent’s 21st birthday, the Court
of Appeals handed down its decision. 

(CA9
2009), amended, 

(2010). No party had
raised any issue of mootness in the Ninth Circuit, and the
Court of Appeals did not address the issue sua sponte.
The court’s opinion discussed only the merits and con
cluded that applying SORNA to juvenile delinquents who
committed their offenses “before SORNA’s passage vio
lates the Ex Post Facto Clause.” 

On that
basis, the court vacated the District Court’s condition of
supervision requiring sex-offender registration and report
ing. 

The United States petitioned for a writ of
certiorari.
  While that petition was pending, this Court entered a
per curiam opinion in this case certifying a preliminary
question of Montana law to the Montana Supreme Court.
560 U. S. ___ (2010). The opinion noted that a “threshold
issue of mootness” might prevent us from reviewing the
decision below on the merits. Id., at ___ (slip op., at 2).
We explained that, because respondent is “no longer . . .
subject” to the District Court’s “sex-offender-registration
conditions,” respondent must “show that a decision invali
dating” those conditions “would be sufficiently likely to
redress ‘collateral consequences adequate to meet Article
III’s injury-in-fact requirement.’ ” Id., at ___ (slip op., at
2–3) (quoting Spencer v. Kemna, 

, 14 (1998)).
We noted that by the time of the Ninth Circuit’s decision,
“respondent had become registered as a sex offender in
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Montana.” 560 U. S., at ___ (slip op., at 3) (internal quota
tion marks omitted). Thus, “[p]erhaps the most likely
potential ‘collateral consequenc[e]’ that might be remedied
by a judgment in respondent’s favor is the requirement
that respondent remain registered as a sex offender under
Montana law.” 

ascertain whether a
decision invalidating the District Court’s registration
conditions would enable respondent to remove his name
from the Montana sex-offender registry, the Court certi
fied the following question to the Montana Supreme
Court:
    “Is respondent’s duty to remain registered as a sex
    offender under Montana law contingent upon the
    validity of the conditions of his now-expired federal
    juvenile-supervision order that required him to regis
    ter as a sex offender, or is the duty an independent
    requirement of Montana law that is unaffected by
    the validity or invalidity of the federal juvenile
    supervision conditions?” Id., at ___ (slip op., at 3)
    (citations omitted).
   The Montana Supreme Court has now responded to our
certified question. See United States v. Juvenile Male, ___
P. 3d ___, 

(2011). Its answer is that
respondent’s “state law duty to remain registered as a sex
offender is not contingent upon the validity of the condi
tions of his federal supervision order, but is an independ
ent requirement of Montana law.” Id., at ___, 

,*1.
                                II
   It is a basic principle of Article III that a justiciable case
or controversy must remain “extant at all stages of review,
not merely at the time the complaint is filed.” Arizonans
for Official English v. Arizona, 

, 67 (1997)
(internal quotation marks omitted). “[T]hroughout the
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                          Per Curiam

litigation,” the party seeking relief “ ‘must have suffered,
or be threatened with, an actual injury traceable to the de
fendant and likely to be redressed by a favorable judicial
decision.’ ” 

(quoting Lewis v. Conti
nental Bank Corp., 

, 477 (1990)).
   In criminal cases, this requirement means that a defen
dant wishing to continue his appeals after the expiration
of his sentence must suffer some “continuing injury” or
“collateral consequence” sufficient to satisfy Article III.
See 

–8. When the defendant chal
lenges his underlying conviction, this Court’s cases have
long presumed the existence of collateral consequences.

see Sibron v. New York, 

, 55–56
(1968). But when a defendant challenges only an expired
sentence, no such presumption applies, and the defendant
must bear the burden of identifying some ongoing “collat
eral consequenc[e]” that is “traceable” to the challenged
portion of the sentence and “likely to be redressed by a
favorable judicial decision.” See 

, 14.
   At the time of the Ninth Circuit’s decision in this case,
the District Court’s order of juvenile supervision had
expired, and respondent was no longer subject to the sex
offender-registration conditions that he sought to chal
lenge on appeal. 560 U. S., at ___ (slip op., at 2). As a
result, respondent’s challenge was moot before the Ninth
Circuit unless he could “show that a decision invalidating”
the District Court’s order would likely redress some collat
eral consequence of the registration conditions. Id., at ___
(slip op., at 2–3) (citing 

).
   As we noted in our prior opinion, one “potential collat
eral consequence that might be remedied” by an order
invalidating the registration conditions “is the require
ment that respondent remain registered” under Montana
law. 560 U. S., at ___ (slip op., at 3) (internal quotation
marks and brackets omitted). But as the Montana Su
preme Court has now clarified, respondent’s “state law
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                               Per Curiam

duty to remain registered as a sex offender is not contin
gent upon the validity of the conditions of his federal
supervision order,” 

, *1, and continues to
apply regardless of the outcome in this case. True, a
favorable decision in this case might serve as a useful
precedent for respondent in a hypothetical lawsuit chal
lenging Montana’s registration requirement on ex post
facto grounds. But this possible, indirect benefit in a
future lawsuit cannot save this case from mootness. See
Camreta v. Greene, 563 U. S. ___, ___ (2011) (slip op., at
16); Commodity Futures Trading Comm’n v. Board of
Trade of Chicago, 

, 656 (CA7 1989) (Posner,
J.) (“[O]ne can never be certain that findings made in a
decision concluding one lawsuit will not some day . . .
control the outcome of another suit. But if that were
enough to avoid mootness, no case would ever be moot”).
  Respondent also argues that this case “cannot be con
sidered moot in any practical sense” because, under cur
rent law, respondent may have “an independent duty to
register as a sex offender” under SORNA itself. Brief in
Opposition 6.2 But the duty to register under SORNA is
not a consequence—collateral or otherwise—of the District
Court’s special conditions of supervision. The statutory
duty to register is, as respondent notes, an obligation that
exists “independent” of those conditions. That continuing
obligation might provide grounds for a pre-enforcement
challenge to SORNA’s registration requirements. It does
not, however, render the current controversy regarding
the validity of respondent’s sentence any less moot.
  Respondent further argues that this case falls within
——————
  2 See 

. §16911(8) (SORNA applicable if the juvenile was “14

years of age or older at the time of the offense and the offense adjudi
cated was comparable to or more severe than aggravated sexual abuse
(as described in section 2241 of title 18)”); 72 Fed. Reg. 8897 (codified at
28 CFR pt. 72) (SORNA’s requirements extend to sex offenders con
victed before the statute’s enactment).
                 Cite as: 564 U. S. ____ (2011)                  7

                          Per Curiam

the established exception to mootness for disputes that are
“ ‘capable of repetition, yet evading review.’ ” 

(quoting Weinstein v. Bradford, 

, 148–149
(1975) (per curiam)). This exception, however, applies
only where “(1) the challenged action [is] in its duration
too short to be fully litigated prior to cessation or expira
tion, and (2) there [is] a reasonable expectation that the
same complaining party [will] be subject to the same
action again.” 

(internal quotation
marks omitted). At the very least, respondent cannot
satisfy the second of these requirements. He has now
turned 21, and he will never again be subject to an order
imposing special conditions of juvenile supervision. See,
e.g., DeFunis v. Odegaard, 

(1974) (per cu
riam). The capable-of-repetition exception to mootness
thus does not apply, and the Ninth Circuit lacked
the authority under Article III to decide this case on the
merits.
    The petition for a writ of certiorari and respondent’s
motion to proceed in forma pauperis are granted. The
judgment of the Court of Appeals is vacated, and the case
is remanded with instructions to dismiss the appeal.

                                                  It is so ordered.

  JUSTICE GINSBURG, JUSTICE BREYER, and JUSTICE
SOTOMAYOR would remand the case to the Ninth Circuit
for that court’s consideration of mootness in the first
instance.

  JUSTICE KAGAN took no part in the consideration or
decision of this case.