In 2002, the Supreme Court ruled in Atkins v. Virginia1 that the Eighth Amendment prohibits the execution of defendants with intellectual disability.2 However, the Court declined to establish a uniform protocol for identifying protected individuals, instead leaving to the states “the task of developing appropriate ways to enforce the constitutional restriction upon [their] execution of sentences.”3 Subsequently, the Florida Supreme Court construed Florida’s criminal code to bar any person with an IQ over 70 from offering evidence of intellectual disability.4 Last Term, in Hall v. Florida,5 the U.S. Supreme Court found that such a bar violates the Eighth and Fourteenth Amendments by “creat[ing] an unacceptable risk that persons with intellectual disability will be executed.”6 In finding Florida’s evidentiary process insufficient to vindicate Atkins’s substantive guarantee, the Court relied on “strong evidence of consensus” against a 70-point IQ cutoff.7 Inquiry into national consensus to evaluate a largely procedural point was not inevitable and, unless Hall is convincingly limited, could create a precedential toehold for challenges to other outlier sentencing practices.
In 1978, twenty-one-year-old Karol Hurst, then seven months pregnant, was abducted, sexually assaulted, and shot dead.8 Freddie Lee Hall and his codefendant, Mack Ruffin, were arrested and convicted for Hurst’s murder.9 Hall received a death sentence, which the Florida Supreme Court affirmed.10 In 1987, the U.S. Supreme Court decided Hitchcock v. Dugger,11 holding that a capital sentencer must consider all relevant mitigating evidence the defendant presents.12 Relying on Hitchcock, Hall challenged his sentence in state court and was ultimately granted a new sentencing proceeding.13 At resentencing, the trial court cited Hall’s intellectual disability as a mitigating factor but nevertheless imposed the death sentence again.14 After the U.S. Supreme Court decided Atkins, Hall moved to vacate his sentence on the grounds that his intellectual disability exempted him from the death penalty.15 Although Hall had previously been judged “probably somewhat retarded”16 and had previously presented an IQ score of 60,17 Hall failed to establish an IQ of 70 or below at his Atkins hearing, rendering him incapable of satisfying Florida’s intellectual disability standard.18 The court therefore denied relief, and Hall appealed.19
The Florida Supreme Court affirmed.20 To prove intellectual disability under Florida law, a defendant must show “significantly subaverage general intellectual functioning existing concurrently with deficits in adaptive behavior and manifested during the period from conception to age 18.”21 “[S]ignificantly subaverage general intellectual functioning”22 is statutorily defined as “performance that is two or more standard deviations from the mean score on a standardized intelligence test.”23 Relying on a precedential interpretation of this provision that created a rigid 70-point IQ cutoff for intellectual disability claims,24 the court rejected Hall’s contention that his IQ scores ought to be interpreted as part of a range.25 Moreover, the court found no error in the trial court’s refusal to permit Hall to present evidence of deficits in adaptive behavior; because Florida’s intellectual disability standard requires both subaverage intellect and adaptive deficits, Hall’s failure to prove subaverage intellect was dispositive.26 Finally, the court found no error in the trial court’s refusal to consider evidence of Hall’s intellectual disability from past sentencing hearings.27 Relying on the U.S. Supreme Court’s decision in Bobby v. Bies,28 the court noted that “[m]ental retardation as a mitigator and mental retardation under Atkins . . . are discrete legal issues.”29 Thus, the court denied relief.30
The Supreme Court reversed.31 Writing for the majority, Justice Kennedy32 found Florida’s scheme unconstitutional because it “contravene[d] our Nation’s commitment to dignity and its duty to teach human decency as the mark of a civilized world.”33 After noting that executing the intellectually disabled serves “[n]o legitimate penological purpose”34 and threatens trial integrity,35 the Court proceeded to determine “how intellectual disability must be defined in order to implement these principles and the holding of Atkins.”36
The Court first inquired into “the medical community’s opinions” because “[s]ociety relies upon medical and professional expertise to define and explain how to diagnose the mental condition at issue.”37 The Court found that Florida’s “mandatory cutoff” contravened professional practice in two ways: First, it left courts unable to consider evidence of intellectual disability, such as medical and behavioral histories, for a defendant with an IQ above the cutoff, “even though the medical community accepts that all of this evidence can be probative of intellectual disability, including for [such] individuals.”38 Second, it failed to account for the fact that each IQ test has a “standard error of measurement” (SEM),39 and that professionals therefore agree that an IQ score “should be read not as a single fixed number but as a range.”40
The Court next considered “objective indicia of society’s standards.”41 Finding “at most nine States [that] mandate a strict IQscore cutoff at 70,”42 the Court concluded that “in 41 States an individual in Hall’s position . . . would not be deemed automatically eligible for the death penalty.”43 Furthermore, because “[c]onsistency of the direction of change is also relevant,”44 the Court emphasized that “every state legislature to have considered the issue after Atkins — saveVirginia’s — and whose law has been interpreted by its courts has taken a position contrary to that of Florida.”45 The Court read these objective indicia as “strong evidence of consensus that our society does not regard [a 70-point] cutoff as proper or humane.”46
Finding this evidence of consensus instructive, the Court proceeded to exercise the “independent judgment” that is “the Court’s judicial duty” when assessing a death penalty practice.47 Given its understanding that clinical definitions of intellectual disability were a “fundamental premise of Atkins,”48 the Court found that “a State must afford [IQ] test scores the same studied skepticism that those who design and use the tests do.”49 Ultimately, the Court found it inappropriate to make one factor “dispositive of a conjunctive and interrelated assessment” and therefore held that “when a defendant’s IQ test score falls within the test’s acknowledged and inherent margin of error, the defendant must be able to present additional evidence of intellectual disability, including testimony regarding adaptive deficits.”50
Justice Alito dissented.51 He disparaged the majority’s use of “the evolving standards of professional societies” as a benchmark for national consensus.52 Looking instead to legislative enactments as democratic indicators of society’s standards, Justice Alito found that “the same absence of a consensus that th[e] Court found in Atkins persists today.”53 According to Justice Alito’s tally, “of the death-penalty states, 10 (including Florida) do not require that the SEM be taken into account, 12 consider the SEM, and 9 have not taken a definitive position on this question.”54 Moreover, the dissent faulted the majority for including non–death penalty states in its calculations because “[t]he fact that a State has abolished the death penalty says nothing about how that State would resolve the evidentiary problem of identifying defendants who are intellectually disabled.”55
Further, Justice Alito noted that he would not strike down Florida’s system even if there were a contrary national consensus sufficient to require the Court to “look beyond the evidence of societal standards.”56 First, Justice Alito defended Florida’s threshold reliance on IQ scores, noting that professionals consider IQ score “the best measure of intellectual functioning.”57 He found no fault with Florida’s refusal to permit a defendant with an IQ above the cutoff to present evidence of adaptive deficit because even strong evidence of adaptive deficit does not prove subaverage intelligence — without which “a person simply cannot be classified as intellectually disabled.”58 Second, Justice Alito defended Florida’s use of IQ score as a fixed number. Each IQ test has its own SEM,59 and that SEM can be used to construct any number of different confidence intervals.60 The range corresponding to any given IQ score therefore depends both on the IQ test used and on the desired level of confidence that the “true” IQ falls within that range. Because “[t]he appropriate confidence level is ultimately a judgment best left to legislatures” and because “Florida’s system already accounts for the risk of testing error by allowing the introduction of multiple test scores,”61 Justice Alito would have affirmed.62
Despite Hall’s emphasis on procedural reliability, the Court employed a national consensus test typically used to identify capital punishment’s substantive limits. Unless convincingly limited, Hall could plausibly be read to extend national consensus inquiry into the realm of procedure. Given the Court’s readiness to find national consensus against substantive death penalty practices, such a reading could open long-accepted outlier sentencing practices to renewed attack.
Eighth Amendment death penalty jurisprudence falls roughly into two categories.63 The first category defines the substantive limits of acceptable punishment with reference to the “evolving standards of decency that mark the progress of a maturing society,”64 as evidenced by objective indicia of national consensus.65 Originally, the Eighth Amendment’s Cruel and Unusual Punishments Clause was understood to prohibit only extreme or torturous types of punishment.66 The Court has expanded this initial categorical understanding to require that punishments “be graduated and proportioned to [the] offense,”67 such that an otherwise constitutional punishment can violate the Eighth Amendment if it is disproportionate to the underlying offense.68 In the capital punishment context, courts rely on national consensus in assessing whether a given method of execution is categorically cruel and unusual,69 and whether the death penalty is disproportionate when applied to a given category of crime70 or offender.71
The second category requires that the process by which a state identifies the death-eligible be sufficiently reliable to encourage confidence in its outcomes. Although reliability in capital sentencing implicates due process,72 it also comes within the Court’s Eighth Amendment jurisprudence.73 Justice Stewart, joining the Court in invalidating the death penalty as practiced in 1972,74 famously noted that arbitrary imposition of the death penalty is “cruel and unusual in the same way that being struck by lightning is cruel and unusual.”75 While some early process cases inquired into national consensus,76 the Court has typically weighed challenged processes against precedential notions of fair process rather than against other states’ contemporary practices.77 Indeed, in a 1984 decision finding no constitutional defect in allowing a trial judge to override a capital sentencing jury’s recommendation of mercy, the Court noted that “[t]he Eighth Amendment is not violated every time a State reaches a conclusion different from a majority of its sisters over how best to administer its criminal laws.”78 As recently as 2012, the Court remarked that it need not “tall[y] legislative enactments” when issuing a decision that “does not categorically bar a penalty for a class of offenders or type of crime . . . [but that] mandates only that a sentencer follow a certain process.”79
Hall seemingly bridges these two categories. The case’s central question of “how intellectual disability must be defined”80 could plausibly be read as either a substantive or a procedural conundrum. On the one hand, by pegging its understanding of intellectual disability to clinical definitions,81 Atkins may have created a substantive protection yoked to professional diagnoses.82 On this reading, Atkins protects those whom medical consensus recognizes as intellectually disabled, and Hall simply relied on national consensus to identify today’s protected class.83 On the other hand, this reading sits oddly with what Hall ultimately established: a constitutional baseline as to when a state must admit evidence of intellectual disability, but no new guidance on what that evidence must show to establish such a disability.84 Thus, in ruling on how a state may “implement the protections of Atkins,”85 Hall may be better read as establishing a procedural guarantee aimed at vindicating a preexisting substantive right. On the latter reading, it was not inevitable that the Court would look to national consensus when assessing the reliability of Florida’s sentencing procedures.86
Insofar as the latter reading expands the use of national consensus inquiry, death penalty abolitionists may embrace it. After all, the Court’s national consensus methodology has grown increasingly friendly toward abolition. In 1977, the Court found national consensus against imposing the death penalty for the rape of an adult when only one state authorized such a penalty.87 Five years later, the Court found a national consensus against imposing the death penalty on accomplices to felony murder because “only about a third of American jurisdictions” authorized the death penalty for such defendants.88 By Atkins, in 2002, a “bare” eighteen states were sufficient to form a consensus,89 with the Court explaining that “[i]t is not so much the number of these States that is significant, but the consistency of the direction of change.”90 Three years later, against a similar legislative tally, the Court found consensus against the juvenile death penalty despite an even “slower pace of abolition” because the “consistent direction of the change” was toward abolition.91 Hall’s inclusion of abolitionist states in its national consensus inquiry into a question of evidentiary procedure,92 as well as Hall’s characterization of “psychiatric and professional studies” as relevant to the question of consensus,93 demonstrates that the Court continues to employ national consensus aggressively against challenged death penalty practices.
Therefore, unless Hall’s methodology is persuasively confined to the diagnostic context, the extension of national consensus inquiry into the procedural realm could threaten other outlier sentencing practices. Most germane to Hall, states permitting intellectually disabled defendants to prove their disability by a mere preponderance of the evidence well outnumber those that impose a more stringent burden of proof.94 Ambitious litigants could seek to extend national consensus inquiry still further into capital procedure. Given that both heightened-reliability procedural guarantees and proportionality-based substantive guarantees are rooted in the concern that the death penalty be imposed on only the most culpable,95 it is arguably arbitrary to apply a distinct methodology to each type of case. Under this logic, all manner of outlier practices could become assailable.96 For example, state schemes permitting a jury to return a death sentence without unanimity could run against national consensus.97 Still further, capital sentencing schemes in which the jury’s sentence is not final — long recognized as constitutional98 — might not survive a national consensus inquiry.99 Indeed, last Term, Justice Sotomayor, joined by Justice Breyer, drew on national consensus when dissenting from a denial of certiorari on Alabama’s practice of allowing judges to overturn a capital sentencing jury’s recommendation of mercy.100
Of course, while such arguments are available, they are hardly assured of success. The death penalty itself is after all an increasingly outlier practice,101 and yet the Court has not in recent years entertained challenges to its constitutionality on that basis,102 even though, as a purely substantive matter, it more clearly merits national consensus analysis than did the point at issue in Hall. But despite Hall’s uncertain future impact, savvy litigants may well find it to be more than the narrow procedural decision it appears at first blush to be.