Cite as: 586 U. S. ____ (2019)                              1

                                   Per Curiam

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SUPREME COURT OF THE UNITED STATES
          TIM SHOOP, WARDEN v. DANNY HILL
   ON PETITION FOR WRIT OF CERTIORARI TO THE UNITED
    STATES COURT OF APPEALS FOR THE SIXTH CIRCUIT
                   No. 18–56. Decided January 7, 2019

   PER CURIAM.
   The United States Court of Appeals for the Sixth Circuit
held that respondent Danny Hill, who has been sentenced
to death in Ohio, is entitled to habeas relief under 

. §2254(d)(1) because the decisions of the Ohio
courts concluding that he is not intellectually disabled
were contrary to Supreme Court precedent that was clearly
established at the time in question. In reaching this de-
cision, the Court of Appeals relied repeatedly and exten-
sively on our decision in Moore v. Texas, 581 U. S. ___
(2017), which was not handed down until long after the
state-court decisions.
   The Court of Appeals’ reliance on Moore was plainly
improper under §2254(d)(1), and we therefore vacate that
decision and remand so that Hill’s claim regarding intel-
lectual disability can be evaluated based solely on holdings
of this Court that were clearly established at the relevant
time.
                              I
   In September 1985, 12-year old Raymond Fife set out on
his bicycle for a friend’s home. When he did not arrive, his
parents launched a search, and that evening his father
found Raymond—naked, beaten, and burned—in a wooded
field. Although alive, he had sustained horrific injuries
2                      SHOOP v. HILL

                         Per Curiam

that we will not describe. He died two days later.
   In 1986, respondent Danny Hill was convicted for tor-
turing, raping, and murdering Raymond, and he was
sentenced to death. An intermediate appellate court
affirmed his conviction and sentence, as did the Ohio
Supreme Court. We denied certiorari. Hill v. Ohio, 

(1993).
   After unsuccessful efforts to obtain postconviction relief
in state and federal court, Hill filed a new petition in the
Ohio courts contending that his death sentence is illegal
under Atkins v. Virginia, 

(2002), which held
that the Eighth Amendment prohibits the imposition of a
death sentence on a defendant who is “mentally retarded.”
In 2006, the Ohio trial court denied this claim, App. to Pet.
for Cert. 381a–493a, and in 2008, the Ohio Court of Ap-
peals affirmed, State v. Hill, 

, 2008-
Ohio-3509, 

. In 2009, the Ohio Supreme
Court denied review. State v. Hill, 

,
2009-Ohio-4233, 

.
   In 2010, Hill filed a new federal habeas petition under

. §2254, seeking review of the denial of his At-
kins claim. The District Court denied the petition, App. to
Pet. for Cert. 77a–210a, but the Sixth Circuit reversed and
granted habeas relief under §2254(d)(1), which applies
when a state-court adjudication “resulted in a decision
that was contrary to, or involved an unreasonable applica-
tion of, clearly established Federal law, as determined by
the Supreme Court of the United States.” See Hill v.
Anderson, 

(2018). The Sixth Circuit found
two alleged deficiencies in the Ohio courts’ decisions: First,
they “overemphasized Hill’s adaptive strengths”; and
second, they “relied too heavily on adaptive strengths that
Hill exhibited in the controlled environment of his death-
row prison cell.” 

In reaching these conclu-
sions, the court relied repeatedly on our decision in Moore
v. Texas, 581 U. S. ___. 

, 487, 488,
                  Cite as: 586 U. S. ____ (2019)            3

                           Per Curiam

n. 4, 489, 491, 492, 493, 495, 496, 498, 500. The court
acknowledged that “[o]rdinarily, Supreme Court decisions
that post-date a state court’s determination cannot be
‘clearly established law’ for the purposes of [the federal
habeas statute],” but the court argued “that Moore’s hold-
ing regarding adaptive strengths [was] merely an applica-
tion of what was clearly established by Atkins.” 

   The State filed a petition for a writ of certiorari, con-
tending that the Sixth Circuit violated §2254(d)(1) because
a fundamental underpinning of its decision was Moore, a
case decided by this Court well after the Ohio courts’
decisions. Against this, Hill echoes the Court of Appeals’
argument that Moore merely spelled out what was clearly
established by Atkins regarding the assessment of adap-
tive skills.
                              II
  The federal habeas statute, as amended by the Antiter-
rorism and Effective Death Penalty Act of 1996 (AEDPA),
imposes important limitations on the power of federal
courts to overturn the judgments of state courts in crimi-
nal cases. The statute respects the authority and ability of
state courts and their dedication to the protection of con-
stitutional rights. Thus, under the statutory provision at
issue here, 

. §2254(d)(1), habeas relief may be
granted only if the state court’s adjudication “resulted in a
decision that was contrary to, or involved an unreasonable
application of,” Supreme Court precedent that was “clearly
established” at the time of the adjudication. E.g., White v.
Woodall, 

, 419–420 (2014); Metrish v. Lan-
caster, 

, 357–358 (2013). This means that a
state court’s ruling must be “so lacking in justification that
there was an error well understood and comprehended in
existing law beyond any possibility for fairminded dis-
agreement.” Harrington v. Richter, 

, 103
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                              Per Curiam

(2011). We therefore consider what was clearly estab-
lished regarding the execution of the intellectually dis-
abled in 2008, when the Ohio Court of Appeals rejected
Hill’s Atkins claim.
   Of course, Atkins itself was on the books, but Atkins
gave no comprehensive definition of “mental retardation”
for Eighth Amendment purposes.1 The opinion of the
Court noted that the definitions of mental retardation
adopted by the American Association on Mental Retarda-
tion and the American Psychiatric Association required
both “subaverage intellectual functioning” and “significant
limitations in adaptive skills such as communication, self-
care, and self-direction that became manifest before age

; see also 

n. 3 (quoting
definitions). The Court also noted that state statutory
definitions of mental retardation at the time “[were] not
identical, but generally conform[ed] to the[se] clinical
definitions.” 

n. 22. The Court then left “ ‘to the
State[s] the task of developing appropriate ways to enforce
the constitutional restriction’ ” that the Court adopted.

(quoting Ford v. Wainwright, 

, 416
(1986) (plurality opinion)).
   More than a decade later, we expounded on the defini-
tion of intellectual disability in two cases. In Hall v.
Florida, 

(2014), we considered a rule re-
stricting Atkins to defendants with “an IQ test score of 70
or 

. We held that this rule violated
the Eighth Amendment because it treated an IQ score
higher than 70 as conclusively disqualifying and thus
prevented consideration of other evidence of intellectual
disability, such as evidence of “deficits in adaptive func-
tioning over [the defendant’s] lifetime.” 

——————
  1 The Court explained that it was “fair to say that a national consen-

sus” had developed against the execution of “mentally retarded” offend-
ers. Atkins v. Virginia, 536 U. S., 304, 316 (2002).
                 Cite as: 586 U. S. ____ (2019)            5

                          Per Curiam

   Three years later in Moore, we applied Hall and faulted
the Texas Court of Criminal Appeals (CCA) for concluding
that the petitioner’s IQ scores, some of which were at or
below 70, established that he was not intellectually dis-
abled. Moore, 581 U. S., at ___–___. We also held that the
CCA improperly evaluated the petitioner’s adaptive func-
tioning. It erred, we concluded, in “overemphasiz[ing]
[petitioner’s] perceived adaptive strengths,” despite the
medical community’s focus on “adaptive deficits.” Id., at
___ (slip op., at 12). And we found that the CCA also went
astray in “stress[ing] [petitioner’s] improved behavior in
prison,” even though the medical community “caution[ed]
against reliance on adaptive strengths developed in a
controlled setting, as a prison surely is.” Id., at ___ (slip
op., at 13) (internal quotation marks omitted).
                             III
  In this case, no reader of the decision of the Court of
Appeals can escape the conclusion that it is heavily based
on Moore, which came years after the decisions of the Ohio
courts. Indeed, the Court of Appeals, in finding an unrea-
sonable application of clearly established law, drew almost
word for word from the two statements in Moore quoted
above. 

(“Contrary to Atkins, the
Ohio courts overemphasized Hill’s adaptive strengths and
relied too heavily on adaptive strengths that Hill exhibited
in the controlled environment of his death-row prison cell.
In so doing, they unreasonably applied clearly established
law”). Although the Court of Appeals asserted that the
holding in Moore was “merely an application of what was
clearly established by 

, the court
did not explain how the rule it applied can be teased out of
the Atkins Court’s brief comments about the meaning of
what it termed “mental retardation.” While Atkins noted
that standard definitions of mental retardation included
as a necessary element “significant limitations in adaptive
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                             Per Curiam

skills . . . that became manifest before age 

, Atkins did not definitively resolve how that ele-
ment was to be evaluated but instead left its application in
the first instance to the States. 

.
  Moreover, the posture in which Moore reached this
Court (it did not arise under AEDPA) and the Moore ma-
jority’s primary reliance on medical literature that post-
dated the Ohio courts’ decisions, 581 U. S., at ___, ___,
provide additional reasons to question the Court of Ap-
peals’ analysis. Cf. Cain v. Chappell, 

,
1024, n. 9 (CA9 2017) (because “Moore is not an AEDPA
case” and was “decided just this spring,” “Moore itself
cannot serve as ‘clearly established’ law at the time the
state court decided Cain’s claim”).
                             IV
   The centrality of Moore in the Court of Appeals’ analysis
is reflected in the way in which the intellectual-disability
issue was litigated below. The Atkins portion of Hill’s
habeas petition did not focus on §2254(d)(1), the provision
on which the decision below is based.2 Instead, it began
and ended with appeals to a different provision of the
habeas statute, §2254(d)(2), which supports relief based on
a state court’s “unreasonable determination of the facts.”
In particular, Hill opened with the claim that the Ohio
courts’ findings on “adaptive functioning” “were an unrea-
sonable determination of the facts in light of the evidence,”
Amended Pet. for Habeas Corpus in No. 96–CV–795 (ND

——————
    2 While
          Hill’s petition argued at one point that certain unidentified
“procedures” used by the state courts in making the relevant decisions
“violated clearly established federal law of Ford/Panetti/Atkins,”
Amended Pet. for Habeas Corpus in No. 96–CV–795 (ND Ohio) (Doc.
94), p. 15, ¶45, the petition plainly did not encompass his current
argument that the Ohio Court of Appeals unreasonably applied clearly
established law under Atkins by overemphasizing adaptive strengths
and improperly considering his prison behavior.
                  Cite as: 586 U. S. ____ (2019)            7

                           Per Curiam

Ohio) (Doc. 94), p. 15, ¶44 (citing §2254(d)(2)), and he
closed with the claim that the state trial court’s assess-
ment that he is “not mentally retarded” was based on “an
unreasonable determination of the facts,” 

¶101 (citing §2254(d)(2)). Indeed, Hill’s reply to the
State’s answer to his petition explicitly “concur[red] . . .
that it is proper to review [his Atkins claim] under
§2254(d)(2).” Traverse in No. 96–CV–795 (ND Ohio) (Doc.
102), p. 47. And so, unsurprisingly, the District Court
analyzed Hill’s Atkins claim solely under §2254(d)(2),
noting that “[a]s Hill concedes in his Traverse, his Atkins
claim is more appropriately addressed as it relates to the
Ohio appellate court’s factual analysis under §2254(d)(2).”
App. to Pet. for Cert. 121a.
   Hill pressed the same §2254(d)(2) argument in his open-
ing brief in the Sixth Circuit. There, he argued that the
state courts’ finding on “adaptive functioning . . . was
an unreasonable determination of the facts.” Brief for
Petitioner–Appellant in No. 14–3718 (CA6), p. 34 (citing
§2254(d)(2)); see also 

(“As such, the state courts’
findings of fact that [Hill] is not mentally retarded consti-
tute an unreasonable determination of facts in light of the
evidence presented. (§2254(d)(2))”).
   It appears that it was not until the Court of Appeals
asked for supplemental briefing on Moore that Hill intro-
duced the §2254(d)(1) argument that the Court of Appeals
adopted. Although, as noted, the Court of Appeals ulti-
mately disclaimed reliance on Moore, it explicitly asked
the parties for supplemental briefing on how Moore
“should be applied to this case.” Because the reasoning of
the Court of Appeals leans so heavily on Moore, its deci-
sion must be vacated. On remand, the court should de-
termine whether its conclusions can be sustained based
strictly on legal rules that were clearly established in the
decisions of this Court at the relevant time.
8                      SHOOP v. HILL

                         Per Curiam

                        *     *   *
  The petition for certiorari and Hill’s motion for leave to
proceed in forma pauperis are granted, the judgment of
the United States Court of Appeals for the Sixth Circuit is
vacated, and the case is remanded for further proceedings
consistent with this opinion.
                                            It is so ordered.