FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

CECILIO GONZALEZ,                         No. 06-56523
             Petitioner-Appellant,
               v.                           D.C. No.
                                         CV-04-09786-DOC
W. A. DUNCAN,
                                            OPINION
            Respondent-Appellee.
                                     
       Appeal from the United States District Court
          for the Central District of California
        David O. Carter, District Judge, Presiding

                  Argued and Submitted
           April 9, 2008—Pasadena, California

                 Filed December 30, 2008

  Before: William C. Canby, Jr., Andrew J. Kleinfeld, and
               Jay S. Bybee, Circuit Judges.

                 Opinion by Judge Bybee




                          16829
16832               GONZALEZ v. DUNCAN


                        COUNSEL

Sean K. Kennedy, Federal Public Defender, Gia Kim
(argued), Deputy Federal Public Defender, Los Angeles, Cali-
fornia, for the petitioner-appellant.

Edmund G. Brown, Jr., Attorney General of the State of Cali-
fornia, Dane R. Gillette, Chief Assistant Attorney General,
Pamela C. Hamanaka, Senior Assistant Attorney General,
Kenneth C. Byrne, Supervising Deputy Attorney General,
Carl N. Henry (argued), Deputy Attorney General, Los Ange-
les, California, for the respondent-appellee.
                        GONZALEZ v. DUNCAN                        16833
                              OPINION



BYBEE, Circuit Judge:

   Cecilio Gonzalez was convicted by a jury of failing to
update his annual sex offender registration within five
working days of his birthday, in violation of California Penal
Code § 290(a)(1)(D).1 Because of his prior criminal convic-
tions, he received a sentence of 28 years to life imprisonment
under California’s “Three Strikes” law. On habeas review, we
must decide whether his sentence violates the Eighth Amend-
ment’s prohibition against cruel and unusual punishment and,
if so, whether the contrary conclusion of the California Court
of Appeal constituted an unreasonable application of clearly
established federal law.

   The California courts have characterized the state’s regis-
tration requirement as a regulatory offense, a “most technical
violation” that “by itself, pose[s] no danger to society.” Peo-
ple v. Cluff, 

, 81, 86 (Cal. Ct. App. 2001).
In a case materially indistinguishable from this one, the Cali-
fornia Court of Appeal concluded that a Three Strikes sen-
tence of 25 years to life imprisonment for violating the
registration requirement was “grossly disproportionate to the
offense” and violated the Eighth Amendment. People v. Car-
mony, 

, 368-69 (Cal. Ct. App. 2005).
Although our standard of review is more deferential, we too
conclude that Gonzalez’s sentence is grossly disproportionate
to his offense. We further conclude that the California Court
of Appeal’s decision affirming Gonzalez’s sentence consti-
tutes an unreasonable application of clearly established fed-
  1
    The provisions of California Penal Code § 290 have since been recodi-
fied to California Penal Code § 290.012. In this opinion, we use the sec-
tion numbers and statutory language corresponding to the charged crimes
when Gonzalez was sentenced.
16834                 GONZALEZ v. DUNCAN
eral law under 28 U.S.C. § 2254(d)(1). We therefore reverse
the district court’s denial of Gonzalez’s petition and remand
with instructions to grant the petition for a writ of habeas cor-
pus.

                                I

   On August 10, 2001, Petitioner Cecilio Gonzalez, a con-
victed sex offender, was charged by information in Los Ange-
les County Superior Court with two felony violations of
California’s sex offender registration statute, California Penal
Code § 290(a)(1)(A), for allegedly failing to register a change
of address on and between May 16, 2000 and May 31, 2001.
The information further alleged that Gonzalez had been con-
victed of three serious or violent felonies that constituted
“strikes” under California’s Three Strikes law.

   Gonzalez pled not guilty. Prior to trial, he moved to pro-
ceed in propria persona. At a pretrial hearing on September 7,
2001, the superior court expressed concern about the possibil-
ity that Gonzalez would receive a life sentence even though
the facts indicated that Gonzalez had attempted to comply
with the registration requirements. The court thus encouraged
Gonzales to accept a plea agreement in exchange for a mid-
term sentence of two years. Gonzalez maintained his inno-
cence and refused to accept a plea. The court granted Gonza-
lez’s motion to proceed pro per.

   On September 10, 2001, the prosecution amended the infor-
mation. Count 1 of the amended information alleged that
Gonzalez failed to register a change of address on and
between May 16, 2000, and May 31, 2001, in violation of
California Penal Code § 290(a)(1)(A), and Count 2 alleged
that he failed to update his registration within five working
days of his February 24, 2001, birthday in violation of Cali-
fornia Penal Code § 290(a)(1)(D). The amended information
retained the allegation of three prior serious or violent felony
convictions under California’s Three Strikes law.
                       GONZALEZ v. DUNCAN                      16835
   Trial began on January 16, 2002. When the superior court
asked if the parties were ready to begin, Gonzalez expressed
his willingness to accept a plea agreement in exchange for a
one year sentence. The court offered a four year sentence,
which Gonzalez declined. Gonzalez moved for a Romero2
hearing to permit the court to strike one or more of his prior
felony convictions for Three Strikes sentencing purposes in
the interest of justice. After a brief hearing, the superior court
declined to strike any of the prior convictions.

   The case proceeded to a jury trial, during which Gonzalez
cross-examined prosecution witnesses and presented a
defense. The government’s theory on Count 1 was that Gon-
zalez had moved twice without updating his sex offender reg-
istration: first, from his grandmother’s house in Lake View
Terrace to his wife’s house in Chatsworth; and second, from
the house in Chatsworth to an apartment he allegedly shared
with his wife in North Hills.

   The government’s basis for Count 2 was that Gonzalez had
failed to update his registration within five working days of
his February 24, 2001, birthday. Testimony established that
the California Department of Corrections notified Gonzalez of
his duty to register annually within five working days of his
birthday on May 2, 2000. Gonzalez registered his Lake View
Terrace address on May 23, 2000, nine months before his
February 24, 2001, birthday. On the registration form, Gonza-
lez initialed the statement: “I must annually, within 5 working
days of my birthday, go to the law enforcement agency hav-
ing jurisdiction over my location or place of residence and
update my registration information.” Gonzalez, however, did
not update his registration until May 21, 2001, within one
year of being advised of his duty to report annually, but three
months after his birthday.
  2
   See People v. Superior Court (Romero), 

 (Cal. 1996).
16836                    GONZALEZ v. DUNCAN
   On January 23, 2002, the jury acquitted Gonzales of failing
to register a change of address but convicted him of failing to
update his registration annually within five working days of
his birthday. At a bench trial to determine the validity of Gon-
zalez’s prior convictions, the prosecutor introduced abstracts
of judgment for a 1988 conviction for cocaine possession, a
1989 conviction for committing a lewd act with a child under
14 years of age, a 1989 conviction for attempted rape by force,3
and a 1992 conviction for second-degree robbery. The supe-
rior court found three prior serious or violent felony convic-
tions under California’s Three Strikes law4 and three prior
prison terms, which each triggered additional one-year sen-
tence enhancements under California law.5 Gonzalez renewed
his Romero motion to strike his prior convictions, which the
superior court denied. The superior court sentenced Gonzalez
to an indeterminate period of 28 years to life imprisonment.
The California Court of Appeal affirmed the sentence in an
eight page unpublished opinion, and the California Supreme
Court declined to hear the case on direct appeal.

   Gonzalez filed state habeas petitions in the California Court
of Appeal and the California Supreme Court, which were both
summarily denied. Gonzalez then filed this 28 U.S.C. § 2254
petition for a writ of habeas corpus in the United States Dis-
  3
     The 1989 lewd act and attempted rape convictions arose from a single
incident.
   4
     Under the Three Strikes law, a defendant with a current felony convic-
tion and no fewer than two prior serious or violent felony convictions must
be sentenced to an indeterminate period of life imprisonment, with the
minimum term calculated as the greater of three times the punishment for
each current felony conviction, or 25 years. Cal. Penal Code
§§ 667(e)(2)(A) & 1170.12(c)(2)(A).
   5
     Under California Penal Code § 667.5(b), a defendant convicted of a
felony receives a one-year enhancement for each prior separate prison
term served for any felony, “provided that no additional term shall be
imposed . . . for any prison term served prior to a period of five years in
which the defendant remained free of both prison custody and the com-
mission of an offense which results in a felony conviction.”
                        GONZALEZ v. DUNCAN                        16837
trict Court for the Central District of California. A magistrate
judge recommended denying Gonzalez habeas relief, and the
district court adopted the recommendation and entered judg-
ment dismissing the petition. Gonzalez timely filed a notice
of appeal and applied for a certificate of appealability. We
certified one issue: “whether appellant’s sentence of 28 years-
to-life under California’s Three Strikes law violates the
Eighth Amendment.”6

                                   II

   We review the district court’s denial of a 28 U.S.C. § 2254
petition for a writ of habeas corpus de novo. Silva v. Wood-
ford, 

, 835 (9th Cir. 2002). Applying the defer-
ential standard of review of the Antiterrorism and Effective
Death Penalty Act (AEDPA), we will not disturb the deci-
sions of the California state courts with respect to Gonzalez’s
Eighth Amendment claim unless the state court’s resolution of
that claim “was contrary to, or involved an unreasonable
application of, clearly established Federal law, as determined
by the Supreme Court.” 28 U.S.C. § 2254(d); see also Wil-
liams v. Taylor, 

, 405-06 (2000); Ramirez v. Cas-
tro, 

, 762 (9th Cir. 2004). Furthermore, we
presume that factual findings made by a state court are correct
unless the petitioner rebuts that presumption with clear and
convincing evidence. 28 U.S.C. § 2254(e)(1).

                                   III

  [1] The Eighth Amendment mandates that “[e]xcessive bail
shall not be required, nor excessive fines imposed, nor cruel
and unusual punishments inflicted.” “The final clause prohib-
  6
   Gonzalez raises two uncertified issues in his opening brief, which we
construe as a motion to expand the Certificate of Appealability. See 9th
Cir. R. 22-1(e). Because Gonzalez failed to make “a substantial showing
of the denial of a constitutional right” with respect to those issues, we
deny that motion. See 28 U.S.C. § 2253(c)(2).
16838                GONZALEZ v. DUNCAN
its not only barbaric punishments, but also sentences that are
disproportionate to the crime committed.” Solem v. Helm, 

, 284 (1983). Reviewing its Eighth Amendment juris-
prudence, the Court has stated that “one governing legal prin-
ciple emerges as ‘clearly established’ under § 2254(d)(1): A
gross disproportionality principle is applicable to sentences
for terms of years.” Lockyer v. Andrade, 

, 72
(2003). The “ ‘precise contours’ of [the gross disproportion-
ality principle] ‘are unclear,’ ” and “applicable only in the
‘exceedingly rare’ and ‘extreme’ case.” Id. at 72-73 (quoting
Harmelin v. Michigan, 

, 998, 1001 (1991) (Ken-
nedy, J., concurring in part and concurring in judgment)).
Five Supreme Court decisions supply guidance on how gross
disproportionality review operates in practice.

   First, in Rummel v. Estelle, the Court considered the impo-
sition of a life sentence with the possibility of parole within
12 years under a Texas recidivist sentencing statute. 

, 265-66, 268 (1980). Rummel was convicted of a felony
for obtaining $120.75 by false pretenses; he had prior felony
convictions for fraudulently using a credit card to obtain $80
worth of goods or services and for passing a forged check in
the amount of $28.36. Id. at 265-66. The Court upheld the
sentence but cautioned that its decision did not mean “that a
proportionality principle would not come into play in the
extreme example [of] a legislature [making] overtime parking
a felony punishable by life imprisonment.” Id. at 274 n.11.

   By contrast, in Solem v. Helm, the Court held that imposi-
tion of a life sentence without the possibility of parole under
South Dakota’s recidivist sentencing statute was grossly dis-
proportionate to the triggering offense of uttering a “no
account” check for $100. 

, 281-82, 284 (1983).
Ordinarily, the maximum punishment for this offense would
have been five years imprisonment and a $5,000 fine; how-
ever, Helm had three prior third degree burglary convictions,
as well as single convictions for obtaining money under false
pretenses, grand larceny, and third-offense driving while
                     GONZALEZ v. DUNCAN                   16839
intoxicated. Id. at 279-81. All of Helm’s crimes were “nonvi-
olent, none was a crime against a person, and alcohol was a
contributing factor in each case.” Id. at 280.

   [2] The Court announced three objective factors to guide
review of a sentence for a term of years under the Eighth
Amendment. First, a reviewing court must look to the gravity
of the offense and the harshness of the penalty. Id. at 290-91.
The Court noted that “Helm’s crime was one of the most pas-
sive felonies a person could commit,” involving neither vio-
lence nor threat of violence to any person, and the Court
further reasoned that Helm’s prior felonies were all relatively
minor. Id. at 296-97 (internal quotation marks omitted). Sec-
ond, the Court stated that “it may be helpful to compare the
sentences imposed on other criminals in the same jurisdic-
tion.” Id. at 291. Applying this factor, the Court found that
Helm’s offense was much less severe than the other crimes
punishable by life imprisonment without possibility of parole
in South Dakota, which included murder, treason, first-degree
manslaughter, first-degree arson and kidnaping. Id. at 298.
Finally, the majority explained that reviewing “courts may
find it useful to compare the sentences imposed for commis-
sion of the same crime in other jurisdictions.” Id. at 291. On
this point, the Court found that Helm’s sentence was more
severe than that authorized for the same crime in all but one
other state. Id. at 299. The Court concluded that Helm’s sen-
tence violated the Eighth Amendment. Id. at 303.

   In a third case, Harmelin v. Michigan, the Court upheld a
life sentence without the possibility of parole for possession
of more than 650 grams of cocaine. 

, 961, 996
(1991). With respect to the general principles of gross dispro-
portionality review, no opinion commanded a majority of the
Court. Seven members of the Court agreed, however, that the
Eighth Amendment contains a gross disproportionality princi-
ple, although they disagreed as to the factors that comprise it.
Id. at 996-97 (Kennedy, J., concurring in part and concurring
16840                 GONZALEZ v. DUNCAN
in the judgment); id. at 1009 (White, J., dissenting); id. at
1027 (Marshall, J., dissenting).

   Justice Kennedy’s opinion, joined by Justices O’Connor
and Souter, represented the narrowest view of a majority of
the Court on the question of gross disproportionality review.
See Marks v. United States, 

, 193 (1977). Under
Justice Kennedy’s view, the Eighth Amendment “does not
require strict proportionality between crime and sentence.
Rather, it forbids only extreme sentences that are ‘grossly dis-
proportionate’ to the crime.” Harmelin, 501 U.S. at 1001
(Kennedy, J., concurring in part and concurring in the judg-
ment) (quoting Helm, 463 U.S. at 288, 303). Though he
acknowledged the three factors set forth in Helm, Justice Ken-
nedy thought that the case “did not announce a rigid three-part
test.” Id. at 1004. Rather, he thought the Court should initially
examine the “crime committed and the sentence imposed” and
only proceed with intrajurisdictional and interjurisdictional
analyses “in the rare case[s]” where the initial examination
“leads to an inference of gross disproportionality.” Id. at
1005-06.

   Applying this methodology, Justice Kennedy concluded
that Harmelin’s sentence, when compared with his crime, did
not give rise to an inference of gross disproportionality, and
thus that no further inquiry was required. Id. at 1008-09. Con-
trasting Harmelin’s offense with the crime considered by the
Court in Helm, he observed that, while utterance of a no
account check was “one of the most passive felonies a person
could commit,” possession of a large quantity of cocaine
“threatened to cause grave harm to society” because of the
association between drugs and violent crime. Id. at 1002
(internal quotation marks omitted); accord Taylor v. Lewis,

, 1099 (9th Cir. 2006) (upholding, on habeas
review, a sentence of 25 years to life imprisonment under Cal-
ifornia’s Three Strikes law for possession of 0.036 grams of
cocaine).
                         GONZALEZ v. DUNCAN                         16841
   In a fourth case, Ewing v. California, the Court upheld a
Three Strikes sentence of 25 years to life imprisonment for
felony grand theft of personal property in excess of $400. 

, 30-31 (2003). The defendant’s prior convictions
included three counts theft, one count grand theft auto, one
count battery, four counts burglary, one count possession of
drug paraphernalia, one count unlawful possession of a fire-
arm, at least one count trespassing, and one count robbery. Id.
at 18-19. There was no majority opinion but Justice
O’Connor’s opinion, joined by Chief Justice Rehnquist and
Justice Kennedy, represents the narrowest basis for the
Court’s decision.7 Justice O’Connor weighed the gravity of
the triggering offense against the harshness of the penalty,
factoring in Ewing’s “long history of felony recidivism” in its
calculation. Id. at 29 (opinion of O’Connor, J.). The plurality
first rejected the defendant’s attempt to downplay the serious-
ness of his offense, and offered the following analysis:

      Even standing alone, Ewing’s theft should not be
      taken lightly. His crime was certainly not “one of the
      most passive felonies a person could commit.” To
      the contrary, the Supreme Court of California has
      noted the “seriousness” of grand theft in the context
      of proportionality review.

Id. at 28 (internal citation omitted). The plurality then con-
cluded that Ewing’s sentence of 25 years to life imprisonment
“reflect[ed] a rational legislative judgment, entitled to defer-
ence, that offenders who have committed serious or violent
felonies and who continue to commit felonies must be inca-
pacitated.” Id. at 30.
  7
    Justices Scalia and Thomas, concurring only in the judgment, con-
cluded that the Eighth Amendment contains no proportionality principle
at all. Id. at 31-32 (Scalia, J., concurring in the judgment); id. (Thomas,
J., concurring in the judgment). This view, however, was clearly rejected
by the plurality and by the four dissenters. Id. at 23-24 (opinion of
O’Connor, J.); id. at 32-33 (Stevens, J., dissenting).
16842                GONZALEZ v. DUNCAN
   Finally, in Lockyer v. Andrade, the Court upheld on federal
habeas review a Three Strikes sentence of 25 years to life
imprisonment for two petty theft convictions arising from the
theft of $153.54 worth of videotapes. 

, 77 (2003).
The defendant’s prior convictions included two counts of mis-
demeanor theft, at least three counts of residential burglary,
and two counts of transportation of marijuana. Id. at 66-67.
Applying AEDPA’s deferential standard of review, the Court
declared that “[t]he facts here fall in between the facts in
Rummel and the facts in Solem[,] . . . [a]nd while this case
resembles to some degree both Rummel and Solem, it is not
materially indistinguishable from either.” Id. at 74. The Court
thus held that the California court decision was not contrary
to clearly established Supreme Court precedent. Id. Applying
the “unreasonable application” clause, the Court first noted
the substantial uncertainty among its membership “regarding
the application of the proportionality principle to the Califor-
nia three strikes law.” Id. at 76. The majority then reiterated
that a sentence for a term of years violated the Eighth Amend-
ment only in an extraordinary case. Id. at 77. The Court held
that Andrade’s sentence did not constitute such an extraordi-
nary case and thus that the California Court of Appeal’s affir-
mance of his sentence did not constitute an unreasonable
application of clearly established law. Id.

   The Supreme Court’s Eighth Amendment jurisprudence
establishes that “no penalty is per se constitutional,” and that
“successful challenges to the proportionality of particular sen-
tences [are] exceedingly rare,” Helm, 463 U.S. at 289-90
(quotation marks omitted), and “reserve[d] . . . for only the
extraordinary case.” Andrade, 538 U.S. at 77. Nevertheless,
the Court has stated, as plainly as can be expressed in words,
that “one governing principle emerges as ‘clearly established’
under § 2254(d)(1): A gross proportionality principle is appli-
cable to sentences for terms of years.” Andrade, 538 U.S. at
72.

  Although the principle may be “clearly established,” the
details are not. In Andrade, the Court decried its own “lack of
                      GONZALEZ v. DUNCAN                   16843
clarity regarding what factors may indicate gross proportion-
ality,” id., but declined to clarify the “gross disproportionali-
ty” standard, leaving us with a principle, but no explanation.
As the Court itself framed the AEDPA standard we must
apply here, “the only relevant clearly established law amena-
ble to the ‘contrary to’ or ‘unreasonable application of’ frame-
work is the gross disproportionality principle, the precise
contours of which are unclear.” Id. at 73. Although the
Andrade Court noted that it had in the past largely failed to
supply specific content to the gross disproportionality princi-
ple, the Court nonetheless did not hesitate to apply it. Id. at
76-77; see also Ewing v. California, 

, 28-31
(2003) (plurality opinion) (applying the gross disproportion-
ality principle).

   Following Andrade, we have applied the gross dispropor-
tionality principle in a number of cases. In Ramirez v. Castro,
for example, Ramirez shoplifted a $199 VCR and was con-
victed of one count of petty theft with a prior theft-related
conviction, an offense punishable as a felony under California
law. 

, 756 (9th Cir. 2004). Having been previ-
ously convicted of two nonviolent shoplifting offenses,
Ramirez was sentenced to 25 years to life imprisonment under
California’s Three Strikes law. We first found that Ramirez’s
sentence was “harsh . . . beyond any dispute” and not “justi-
fied by the gravity of his most recent offense and criminal his-
tory.” Id. at 767-68. Finding that “this is the extremely rare
case that gives rise to an inference of gross disproportionali-
ty,” we then conducted an intrajurisdictional and interjurisdic-
tional “comparative analysis” of Ramirez’s sentence. Id. at
770-73. We concluded that the state court had correctly iden-
tified the gross disproportionality principle and that the
court’s decision was thus not “contrary to” Supreme Court
precedent. Id. at 774. However, we held that Ramirez was
entitled to habeas relief because the state court had unreason-
ably applied the gross disproportionality principle to the facts
in Ramirez’s case. Id. at 774-75.
16844                 GONZALEZ v. DUNCAN
   As Nunes v. Ramirez-Palmer, 

 (9th Cir. 2007),
illustrates, however, we have followed the Supreme Court’s
admonition that successful disproportionality challenges
should be rare. In Nunes, the petitioner was sentenced to 25
years to life imprisonment after being convicted of shoplifting
$114.40 worth of tools. Id. at 435. Unlike the petitioner in
Ramirez, however, Nunes had an “extensive felony record”
dating back almost sixty years. Id. at 440. We had little diffi-
culty concluding that Nunes was not entitled to habeas relief.
Id. at 443. In other cases, we have similarly denied habeas
relief to petitioners where the triggering offense involved a
serious crime against life or property and followed a long
criminal history. See, e.g., Taylor v. Lewis, 

,
1101 (9th Cir. 2006) (denying habeas relief to petitioner who
received 25 years to life imprisonment for possessing 0.036
grams of cocaine following a “history of recidivism, marked
by violence and the intentional taking of human life and span-
ning some 30 years”); Rios v. Garcia, 

, 1083
(9th Cir. 2004) (denying habeas relief to petitioner who
received sentence of 25 years to life imprisonment for stealing
$80 worth of watches from a department store following prior
robbery convictions).

                              IV

   Having set forth this background, we now turn to whether
“a threshold comparison of the crime committed and the sen-
tence imposed” in this case “leads to an inference of gross
disproportionality.” Harmelin, 501 U.S. at 1005 (Kennedy, J.,
concurring in part and concurring in the judgment).

A.     Inference of Gross Disproportionality

  1.    Gravity of the Offense

   [3] We weigh the criminal offense and the resulting penalty
“in light of the harm caused or threatened to the victim or to
society, and the culpability of the offender.” Helm, 463 U.S.
                      GONZALEZ v. DUNCAN                   16845
at 292. The statute of conviction, California Penal Code
§ 290(a)(1)(D), requires a registered sex offender to update
his registration annually within five working days of his birth-
day. Violation of that subsection “involve[s] neither violence
nor threat of violence to any person,” Helm, 463 U.S. at 296;
it is purely a regulatory offense. See People v. Barker, 

 345, 354 (2004). “[A] violation of section 290 requires
actual knowledge of the duty to register,” id. at 351, but one
may violate the statute simply by forgetting to register after
having been advised of the duty to do so. Id. at 354.

   The purpose of California’s registration law is to prevent
“recidivism in sex offenders” by assuring they are “available
for police surveillance.” Wright v. Superior Court, 

, 104 (Cal. 1997) (internal quotation marks and citations
omitted). Section 290(a)(1)(A)’s mandate that sex offenders
register any change of address relates directly to the state’s
interest in ensuring that it knows the whereabouts of its sex
offenders. As noted by the California Supreme Court,
“[e]nsuring offenders are readily available for police surveil-
lance depends on timely change-of-address notification.” Id.
at 105 (internal quotation marks and citation omitted). A jury,
however, acquitted Gonzalez of the charge that he violated
this requirement. Accordingly, we adopt the jury’s implicit
determination that Gonzalez was living at his registered
address throughout the relevant time period in this case.

  [4] By contrast, § 290(a)(1)(D)’s annual registration
requirement, which Gonzalez was convicted of violating, is
only tangentially related to the state’s interest in ensuring that
sex offenders are available for police surveillance. Annual
registration is merely a “backup measure to ensure that
authorities have current accurate information.” People v. Car-
mony, 

, 374 (Cal. Ct. App. 2005). Failure
to comply with the annual registration requirement is “the
most technical violation of the section 290 registration
requirement,” and “by itself, pose[s] no danger to society.”
16846                     GONZALEZ v. DUNCAN
People v. Cluff, 

, 81, 86 (Cal. Ct. App.
2001).

   Indeed, we are unable to discern any actual harm resulting
from Gonzalez’s failure to comply with the annual registra-
tion requirement. Gonzalez updated his sex offender registra-
tion nine months before and three months after his February
24, 2001, birthday, and he remained at his last registered
address throughout that time period. There is nothing in the
record remotely indicating that Gonzalez’s failure to rereg-
ister the same address a third time in the same twelve month
period could have interfered with the ability of police to mon-
itor his activities.8 The record confirms that Gonzalez was in
fact “readily available for police surveillance”: Gonzalez was
arrested “fairly close” to his registered address, and the arrest-
ing officers were familiar with Gonzalez and had spoken to
him previously at that location. Id. at 86 (“Cluff was exactly
where he said he would be when he registered in 1995, and
the police were able to quickly find him.”). We conclude that
“[t]he purpose of the registration statute was not undermined
by [Gonzalez’s] failure to annually update his registration.”
Id.

   In reviewing Three Strikes sentences triggered by viola-
tions of the sex offender registration law, California courts
have recognized that the distinction between a conviction for
failure to register after a change of address as required by
§ 290(a)(1)(A), and a conviction for failure to update registra-
tion annually as required by § 290(a)(1)(D), is critical. In Peo-
  8
    We recognize that administrative efficiency requires California to des-
ignate some benchmark, such as the registrant’s birthday, for the annual
registration requirement and that California has a legitimate interest in
criminalizing failure to comply with that regulatory requirement. Our anal-
ysis in no way calls into question the constitutional validity of
§ 290(a)(1)(D) or California’s ability to criminalize its violation. We eval-
uate the social justification for the requirement only to determine whether
the Three Strikes sentence imposed in Gonzalez’s case exceeds constitu-
tional limits.
                          GONZALEZ v. DUNCAN                          16847
ple v. Meeks, the Court of Appeal held that imposition of a 25
years to life sentence for failure to register a change of
address and a consecutive sentence of two years imprison-
ment for failure to update registration annually did not violate
the Eighth Amendment.9 

 (Cal. Ct. App.
2004). By contrast, in Carmony, the Court of Appeal held that
a sentence of 25 years to life imprisonment merely for failure
to update registration annually did violate the Eighth Amend-
ment. 26 Cal. Rptr. 3d at 365. The court analyzed the sentence
as follows:

         The purpose of the sex offender registration law is
      to require that the offender identify his present
      address to law enforcement authorities so that he or
      she is readily available for police surveillance. In
      this case the defendant did so one month prior to his
      birthday and was in fact present at his registered
      address when the arrest for the present violation was
      made. The stated purpose of the birthday registration
      requirement was (and still is) to “update” the exist-
      ing registration information.

         Here, there was no new information to update and
      the state was aware of that fact. Accordingly, the
      requirement that defendant re-register within five
      days of his birthday served no stated or rational pur-
      pose of the registration law and posed no danger or
      harm to anyone.
  9
    We note that for purposes of sentencing, the trial court in Meeks struck
the defendant’s prior convictions with respect to his conviction for his fail-
ure to register annually within five days of his birthday. See 

 at 448. Meeks is consistent with Cluff, which held that the trial court
abused its discretion by denying a Romero motion to strike one or more
priors in the interest of justice when sentencing the defendant for failure
to register annually within five days of his birthday. See Cluff, 105 Cal.
Rptr. 2d at 87-88.
16848                      GONZALEZ v. DUNCAN
        Because a 25-year recidivist sentence imposed
     solely for failure to provide duplicate registration
     information is grossly disproportionate to the
     offense, shocks the conscience of the court and
     offends notions of human dignity, it constitutes cruel
     and unusual punishment under both the state and
     federal Constitutions.

Carmony, 26 Cal. Rptr. 3d at 368-69 (internal citation omit-
ted). This case is not materially distinguishable from Car-
mony. Gonzalez registered nine months before and three
months after his February 24, 2001, birthday. The jury found
that he did not change addresses during that time period. The
police were well aware of Gonzalez’s location at all times and
indeed arrested him near his registered address.

   [5] Although we independently evaluate federal constitu-
tional claims, in doing so we are bound by the California
courts’ interpretations of California law. See Powell v. Lam-
bert, 

, 874 (9th Cir. 2004). Accordingly, we fol-
low the Court of Appeal in finding that violation of the annual
registration requirement of § 290(a)(1)(D) alone is “an
entirely passive, harmless, and technical violation of the regis-
tration law.” Carmony, 26 Cal. Rptr. 3d at 372.10
   10
      We note that the Carmony court’s analysis of that provision comports
with common sense, particularly as applied to the circumstances of this
case. To convict Gonzalez of violating § 290(a)(1)(D), the jury found “be-
yond a reasonable doubt that the defendant had actual knowledge of his
duty to register annually within five working days of his birthday and that
he knew what act was required to be performed.” See People v. Garcia,

, 752 (2001) (“In a case like this, involving a failure to act,
we believe section 290 requires the defendant to actually know of the duty
to act.”). While violation of § 290(a)(1)(D) requires “willfulness,” or “ac-
tual knowledge of the duty to register,” id., forgetting to update the regis-
tration during the prescribed five working days after the registrant’s
birthday is not a defense. Barker, 

 at 350 (“forgetting the man-
datory registration requirement of section 290 is simply not a legitimate
defense to the charge of willfully failing to register”). As a result, it is pos-
                          GONZALEZ v. DUNCAN                         16849
  2.    Severity of the Penalty

   [6] Gonzalez’s sentence of 28 years to life is “harsh . . .
beyond any dispute.” Ramirez, 365 F.3d at 767. The indeter-
minate life sentence he received is the third most severe pen-
alty available under California law, exceeded in severity only
by death and life imprisonment without the possibility of
parole. See id. Under the Three Strikes law, Gonzales must
serve a minimum of 28 years before he is eligible for parole.
See Carmony, 26 Cal. Rptr. 3d at 374. In contrast, a defendant
who, without prior strikes, violates § 290(a)(1)(D) by failing
to update his registration annually may only receive a prison
term of between sixteen months and three years. CAL. PENAL
CODE § 290(g)(2). Gonzalez’s minimum sentence is therefore
21 times greater than the statutory minimum and more than
nine times greater than the statutory maximum.11

   [7] In comparison to the passive, harmless, and technical
violation that triggered Gonzalez’s sentence, “the severe pen-
alty imposed on [Gonzalez] appears disproportionate by any
measure.” Cluff, 

 at 87. We recognize, how-
ever, that California has a valid “public-safety interest in inca-
pacitating and deterring recidivist felons.” Ewing, 538 U.S. at
29 (opinion of O’Connor, J.); see also People v. Murphy, 

, 1142 (Cal. 2001) (stating that the purpose of the
Three Strikes law is “to punish recidivism”). Thus, we must
consider the defendant’s criminal history when weighing the

sible that Gonzalez violated § 290(a)(1)(D) through ordinary negligence
by forgetting to register during the mandated five working day period.
Because the record suggests that Gonzalez made a good faith effort to
comply with the registration law, we find that little or no moral culpability
attaches to his violation of § 290(a)(1)(D).
   11
      Gonzalez’s sentence is also a high multiple of the plea offers he
received. See Reyes v. Brown, 

, 969 n.9 (9th Cir. 2005) (hold-
ing that plea offers are relevant to determining whether a Three Strikes
sentence is grossly disproportionate to the triggering offense).
16850                GONZALEZ v. DUNCAN
severity of the penalty. See Ewing, 538 U.S. at 29 (opinion of
O’Connor, J.).

   Gonzalez’s criminal history is extensive, including convic-
tions for possession of a controlled substance and auto theft
in 1988, attempted forcible rape and lewd conduct with a
child under the age of fourteen in 1989, robbery in 1992, and
spousal abuse in 1999. We recognize that Gonzalez’s prior
convictions, which include both crimes of violence and sexual
predation, are very serious. We also acknowledge the state’s
interest in deterring recidivism. Incarceration for a minimum
of 28 years would incapacitate Gonzalez and thus prevent him
from committing additional felonies against the general popu-
lation.

   However, we are unable to discern any rational relationship
between Gonzalez’s failure to update his sex offender regis-
tration annually and the probability that he will recidivate as
a violent criminal or sex offender. There is no evidence that,
as of 2001, Gonzalez was a recidivist. We agree with the Cali-
fornia Court of Appeal’s conclusion in Carmony that a sen-
tence of 25 years to life imprisonment does not “protect the
public when the current offense bears little indication [that
the defendant] has recidivist tendencies to commit offenses
that pose a risk of harm.” Carmony, 26 Cal. Rptr. 3d at 375
(emphasis added).

   [8] Gonzalez’s present offense does not reveal any propen-
sity to recidivate. California certainly may be “justified in
punishing a recidivist more severely than it punishes a first
offender,” Helm, 463 U.S. at 296, where “ ‘the latest crime
. . . is considered to be an aggravated offense because [it is]
a repetitive one,’ ” Witte v. United States, 

, 400
(1995) (quoting Gryger v. Burke, 

, 732 (1948)).
However, what California has done here is fundamentally dif-
ferent. It has imposed an extraordinarily harsh sentence on
Gonzalez based on a violation of a technical regulatory
requirement that resulted in no social harm and to which little
                      GONZALEZ v. DUNCAN                   16851
or no moral culpability attaches. Absent some connection
between Gonzalez’s past violent and sexual offenses, his pres-
ent regulatory violation, and his propensity to recidivate as a
violent or sexual offender, we cannot conclude that Califor-
nia’s interest in deterring and incapacitating recidivist offend-
ers justifies the severity of the indeterminate life sentence
imposed.

   [9] In sum, we conclude that Gonzalez’s sentence raises an
inference of gross disproportionality. We thus turn to a com-
parative analysis of Gonzalez’s sentence. See Harmelin, 501
U.S. at 1005 (Kennedy, J., concurring in part and concurring
in the judgment); Helm, 463 U.S. at 291-92; Ramirez, 365
F.3d at 770.

B.   Intrajurisdictional and Interjurisdictional Comparisons

   [10] Comparison of Gonzalez’s sentence with those
imposed for other crimes in California and for the same crime
in other states confirms our finding of gross disproportion-
ality. See Helm, 463 U.S. at 298-300. Gonzalez’s indetermi-
nate sentence of 28 years to life is substantially more severe
than penalties California imposes for far more serious crimes.
For example, second degree murder is punishable by 15 years
to life, CAL. PENAL CODE §§ 189, 190(a); voluntary man-
slaughter is punishable by three, six, or eleven years, CAL.
PENAL CODE §§ 192(a), 193(a); kidnaping is punishable by
three, five, or eight years, CAL. PENAL CODE §§ 207, 208; first
degree robbery is punishable by three, six, or nine years, CAL.
PENAL CODE §§ 211, 213(a)(1)(A); and rape is punishable by
three, six, or eight years, CAL. PENAL CODE §§ 261, 264(a).
The gross disparity between Gonzalez’s sentence and those
for many serious violent crimes in California underscores that
the Three Strikes sentence imposed on Gonzalez is arbitrarily
harsh and undeniably cruel.

  [11] An interjurisdictional comparison similarly militates
against California’s position. At least eleven states require a
16852                 GONZALEZ v. DUNCAN
sex offender to renew registration within some statutorily
fixed period after the initial registration but do not tie the reg-
istration requirement to the offender’s birthday; Gonzalez’s
failure to update his sex offender registration within several
days of his birthday thus would not have even qualified as a
criminal offense in those states. See ARIZ. REV. STAT. ANN.
§ 13-3821(J); DEL. CODE tit. 11, § 4120(g); IDAHO CODE § 18-
8307(5)(b); IOWA CODE § 692A.4; LA. REV. STAT. ANN.
§ 15:542.1; NEB. REV. STAT. § 29-4006(2); NEV. REV. STAT.
§ 179D.480; N.J. STAT. ANN. § 2C:7-2(e); N.Y. CORRECT. LAW
§ 168-f; PA. CONS. STAT. § 9796; WIS. STAT. § 301.45(3). In at
least ten jurisdictions, a first registration offense is a misde-
meanor. ALASKA STAT. § 11.56.840(b); D.C. CODE § 22-
4015(a); IOWA CODE § 692A.7(1); ME. REV. STAT. ANN. tit. 34-
A, § 11227; MD. CODE ANN., CRIM. PROC. § 11-721; MASS.
GEN. LAWS ch. 6, § 178H(a)(1); MICH. COMP. LAWS
§§ 28.725a(10), 28.729(2); OR. REV. STAT. § 181.599; S.C.
CODE ANN. § 23-3-470(B)(1); W. VA. CODE § 15-12-8(b). In
at least ten states, sex offender registration violations are sub-
ject to separate recidivist statutes but such statutes punish
those who fail to comply with registration requirements only
for terms of imprisonment ranging from one to ten years.
ALASKA STAT. §§ 11.56.835(d), 12.55.125(e); COLO. REV.
STAT.      §§ 16-22-108(1)(b),      18-3-412.5(2)(A),       18-1.3-
401(1)(a)(V)(A); 18-1.3-801(2); CONN. GEN. STAT. §§ 54-254,
53a-35a, 53a-40(c), (j); FLA. STAT. ANN. § 775.084 (1)(b) &
4(b)(3); MASS. GEN. LAWS ch. 6, § 178H, § 178F, ch. 279,
§ 25; MISS. CODE ANN. §§ 45-33-33(2); MO. ANN. STAT.
§§ 589.425(1), 558.016(3), 558.011(1)(3); N.M. STAT. §§ 29-
11A-4(L), (N), 31-18-15(A)(9), 31-18-17(B), (C); N.D. CENT.
CODE §§ 12.1-32-15(9), 12.1-32-09(2)(c); TENN. CODE ANN.
§§ 40-35-112(c)(5), 40-35-106(c), 40-35-107(c), 40-39-
204(c), 40-39-208(b). An even larger number of states appear
not to subject violators of sex offender registration require-
ments to separate recidivist statutes at all.

  Several states authorize maximum recidivist sentences
greater than ten years. See ALA. CODE §§ 13A-5-9(c), 15-20-
                         GONZALEZ v. DUNCAN                          16853
24; GA. CODE ANN. §§ 17-10-7(c), 42-1-12(n); MONT. CODE
ANN. §§ 46-23-507, 46-18-501-502; N.H. REV. STAT. ANN.
§ 651-B:9(II), 651:6(II)(A), (III)(a); OKLA. STAT. tit. 57,
§§ 584(A)(5), 587, tit. 21, § 51.1(C); R.I. GEN. LAWS §§ 11-
37.1-14, 11-37.1-10, 12-19-21(a); S.D. CODIFIED LAWS §§ 22-
24B-2, 22-7-8, 22-6-1(C) (2007). However, Texas appears to
be the only state besides California that would mandate a sen-
tence of 25 years or longer for a third felony offense, includ-
ing a violation of a sex offender registration law. See TEX.
PENAL CODE ANN. § 12.42(d). See also Ramirez, 365 F.3d at
772 (“[T]he [Three Strikes statute] is the most stringent in the
nation.”); Carmony, 26 Cal. Rptr. 3d at 376-78 (compiling
statistics and concluding that “California is the only state that
requires a life sentence with a mandatory prison term of 25
years prior to parole eligibility for a Three Strikes offender
whose violation is noncompliance with the annual registration
requirement.” (emphasis omitted)).

   [12] As we expect in our federal system, sex offender regis-
tration laws vary widely among the several states and are fre-
quently changed.12 We are thus hesitant to draw any
conclusions from this survey; however, the fact that Gonza-
lez’s sentence is at the margin of what the states have deemed
an appropriate penalty for violation of sex offender registra-
tion laws supports our finding that Gonzalez’s sentence is
unusual. See Helm, 463 U.S. at 299 (“At the very least, there-
fore, it is clear that Helm could not have received such a
severe sentence in 48 of the 50 States.”).

                                    V

  [13] Weighing both the gravity of the commitment offense
and Gonzalez’s criminal history, we conclude that the sen-
  12
    See, e.g., Rummel, 445 U.S. at 282 (“Absent a constitutionally
imposed uniformity inimical to traditional notions of federalism, some
State will always bear the distinction of treating particular offenders more
severely than any other State.”).
16854                 GONZALEZ v. DUNCAN
tence imposed of 28 years to life imprisonment is grossly dis-
proportionate to the “entirely passive, harmless, and technical
violation of the registration law,” Carmony, 26 Cal. Rptr. 3d
at 372, and hence that it violates the Eighth Amendment. This
conclusion, however, is insufficient to grant Gonzalez habeas
relief. Indeed, even the California Court of Appeal’s decision
in Carmony does not control our disposition here, although
we may look to it for its persuasive value. Under AEDPA,
Gonzalez is entitled to habeas relief from this court only if the
state court proceedings “resulted in a decision that was con-
trary to, or involved an unreasonable application of, clearly
established Federal law, as determined by the Supreme Court
of the United States.” 28 U.S.C. § 2254(d)(1). A state court’s
decision is an unreasonable application of clearly established
federal law if “the state court identifies the correct governing
legal principle from [Supreme Court] decisions but unreason-
ably applies that principle to the facts of the prisoner’s case.”
Williams, 529 U.S. at 413.

   Here, the Court of Appeal properly stated the objective fac-
tors of Solem v. Helm that guide gross disproportionality
review. Moreover, the facts of Gonzalez’s case are not “mate-
rially indistinguishable” from any decision of the United
States Supreme Court. See Williams, 529 U.S. at 406. Thus,
we cannot conclude that the state court’s decision was con-
trary to clearly established law as determined by the Supreme
Court.

   [14] The Court of Appeal failed, however, to apply these
factors reasonably to the facts of Gonzalez’s case. After ini-
tially stating the proper factors, it relied on four general prop-
ositions to affirm Gonzalez’s sentence. It found that (1) the
California Legislature has determined that sex offenders pose
a “continuing threat to society” and must therefore be readily
available for police surveillance by registering under section
290, (2) Gonzalez has a “significant criminal history” reveal-
ing that he “is a recidivist who has resisted prior efforts at
rehabilitation,” (3) Gonzalez’s sentence “is not unlike others
                     GONZALEZ v. DUNCAN                   16855
imposed under the Three Strikes law and upheld by the
courts,” and (4) Gonzalez’s sentence “is consistent with the
nationwide pattern of substantially increasing sentences for
habitual criminals.”

   [15] The state court’s reasoning is unsound. First, the Court
of Appeal vastly overstated the annual registration require-
ment’s relationship to police surveillance. The requirement
that offenders update their addresses is indeed directly related
to the need for police to be able to keep track of offenders but
Gonzalez was acquitted of failing to update his address. The
annual registration requirement set forth in § 290(a)(1)(D), by
contrast, is merely a “backup measure” to ensure that police
have current information. See Carmony, 26 Cal. Rptr. 3d at
374. A violation of § 290(a)(1)(D) “by itself, pose[s] no dan-
ger to society.” Cluff, 

 at 86. The California
courts have thus, as noted above, distinguished between viola-
tions of § 290(a)(1)(D) and § 290(a)(1)(A).

   [16] Second, we agree with the California Court of Appeal
that Gonzalez’s criminal history is not insignificant. However,
Gonzalez’s criminal history alone cannot support a sentence
of 28 years to life imprisonment. The triggering offense in
this case is “remote from and bear[s] no relation to the current
offense and the current offense reveals no tendency to commit
additional offenses that pose a threat to public safety.” Car-
mony, 26 Cal. Rptr. 3d at 375. As a result, imposition of a
Three Strikes sentence in this case is not rationally related to
California’s interest in deterring recidivism.

   Third and contrary to the Court of Appeal’s assertion, Gon-
zalez’s sentence appears to be unlike sentences imposed for
other violations of § 290(a)(1)(D). For example, in Cluff, the
Court of Appeal held that the trial court had abused its discre-
tion in refusing to strike prior convictions when sentencing a
defendant for failure to annually update his registration, 

 at 87-88, and in Carmony, the Court of Appeal
held that imposition of a 25 years to life sentence for failure
16856                    GONZALEZ v. DUNCAN
to update registration annually constituted cruel and unusual
punishment under both the state and federal Constitutions, 

. Finally, while there may well be a general
trend toward more severe penalties for recidivist offenders,
Gonzalez’s sentence appears to be more severe than the maxi-
mum penalty available for similar offenses in all but one other
state.

   The state court’s analysis resulted in an unreasonable appli-
cation of the Supreme Court’s Eighth Amendment jurispru-
dence. The imposition of a 28 years to life sentence for failure
to update a sex offender registration within five working days
of the registrant’s birthday in this case is more extreme than
the imposition of a sentence of life without parole for utter-
ance of a no account check in Helm. In that case, the Supreme
Court underscored that uttering a no account check was “one
of the most passive felonies a person could commit . . .
involv[ing] neither violence nor threat of violence to any per-
son.” Helm, 463 U.S. at 296. Here, Gonzalez’s failure to
update his sex offender registration annually is a crime of
omission, which is by definition the most passive felony a
person could commit, and one that California courts have
characterized as a “harmless, and technical violation of the
registration law.” Carmony, 26 Cal. Rptr. 3d at 372. Indeed,
the California Court of Appeal specifically held that a viola-
tion of § 290(a)(1)(D) is “less serious than the offense of
uttering a no-account check committed by the defendant in
[Helm].” Id.13

   Although Solem remains the only Supreme Court decision
finding a sentence grossly disproportionate to the triggering
offense, none of the other Supreme Court decisions upholding
  13
    In fact in Carmony, the court found that “[the defendant’s] failure to
register was completely harmless and no worse than a breach of an over-
time parking ordinance,” 26 Cal. Rptr. 3d at 374, a reference to Rummel’s
“extreme example [of] a legislature [making] overtime parking a felony
punishable by life imprisonment.” See Rummel, 445 U.S. at 274 n.11.
                      GONZALEZ v. DUNCAN                   16857
sentences for a term of years—Rummel (false pretenses), Har-
melin (drug possession), Ewing (grand theft) and Lockyer
(petty theft)—involved regulatory offenses. Each of the prop-
erty and drug crimes involved in those cases imposed a read-
ily ascertainable social harm, in sharp contrast to the
“harmless, and technical violation” committed by Gonzalez.

   In addition, in the four Supreme Court decisions upholding
sentences for a term of years, the defendant’s criminal history
was directly related to the triggering offense, evincing a clear
pattern of recidivism. In Rummel the triggering offense of
obtaining $120.75 by false pretenses was related to past con-
victions for fraudulently using a credit card and passing a
forged check. In Ewing, the triggering offense of felony grand
theft was related to prior convictions for theft, grand theft
auto, burglary, trespassing, and robbery. In Andrade, the trig-
gering offenses of two petty theft convictions were related to
prior convictions for misdemeanor theft and residential bur-
glary. Here, Gonzalez’s failure to update his sex offender reg-
istration is categorically different from his past criminal
conduct and does not demonstrate any recidivist tendency
toward violent crime or sex offenses. See Cluff, 

 at 87.

   [17] The disparity between Gonzales’s technical violation
of a regulatory crime of omission and the 28 years to life sen-
tence imposed is so extreme that the state court could uphold
the constitutionality of the sentence only by reading the
“grossly disproportionate” standard out of federal law. The
court in Carmony concluded that “[i]t is beyond dispute that
a life sentence is grossly disproportionate to the [technical
failure to register].” 26 Cal. Rptr. 3d at 374. We agree. The
state court’s application of the gross disproportionality princi-
ple, clearly established by the holding of Solem v. Helm and
reaffirmed by Lockyer v. Andrade, was objectively unreason-
able.
16858              GONZALEZ v. DUNCAN
                           VI

  [18] The judgment of the district court is REVERSED, and
we REMAND with instructions to grant the petition.

  REVERSED and REMANDED.