JUSTICE O'CONNOR delivered the opinion of the Court, except as to Part IV-C.
In this case, we must decide whether petitioner, Johnny Paul Penry, was sentenced to death in violation of the Eighth Amendment because the jury was not instructed that it could consider and give effect to his mitigating evidence in imposing its sentence. We must also decide whether the Eighth Amendment categorically prohibits Penry's execution because he is mentally retarded.
I
On the morning of October 25, 1979, Pamela Carpenter was brutally raped, beaten, and stabbed with a pair of scissors in her home in Livingston, Texas. She died a few hours later in the course of emergency treatment. Before she died, she described her assailant. Her description led two local sheriff's deputies to suspect Penry, who had recently been released on parole after conviction on another rape charge. Penry subsequently gave two statements confessing to the crime, and was charged with capital murder.
At a competency hearing held before trial, a clinical psychologist, Dr. Jerome Brown, testified that Penry was mentally retarded. As a child, Penry was diagnosed as having organic brain damage, which was probably caused by trauma to the brain at birth. App. 34-35. Penry was tested over the years as having an IQ between 50 and 63, which indicates mild to moderate retardation. [ Footnote 1 ] Id. at 36-38, 55. Dr. Brown's own testing before the trial indicated that Penry had an IQ of 54. Dr. Brown's evaluation also revealed that Penry, who was 22 years old at the time of the crime, had the mental age of a 6 1/2-year-old, which means that "he has the ability to learn and the learning or the knowledge of the average 6 1/2-year-old kid." Id. at 41. Penry's social maturity, or ability to function in the world, was that of a 9or 10-year-old. Dr. Brown testified that "there's a point at which anyone with [Penry's] IQ is always incompetent, but, you know, this man is more in the borderline range." Id. at 47.
The jury found Penry competent to stand trial. Id. at 20-24. The guilt-innocence phase of the trial began on March 24, 1980. The trial court determined that Penry's confessions were voluntary, and they were introduced into evidence. At trial, Penry raised an insanity defense and presented the testimony of a psychiatrist, Dr. Jose Garcia. Dr. Garcia testified that Penry suffered from organic brain damage and moderate retardation, which resulted in poor impulse control and an inability to learn from experience. Id. at 18, 19, 87-90. Dr. Garcia indicated that Penry's brain damage was probably caused at birth, id. at 106, but may have been caused by beatings and multiple injuries to the brain at an early age. Id. at 18, 90. In Dr. Garcia's judgment, Penry was suffering from an organic brain disorder at the time of the offense which made it impossible for him to appreciate the wrongfulness of his conduct or to conform his conduct to the law. Id. at 86-87.
Penry's mother testified at trial that Penry was unable to learn in school, and never finished the first grade. Penry's sister testified that their mother had frequently beaten him over the head with a belt when he was a child. Penry was also routinely locked in his room without access to a toilet for long periods of time. Id. at 124, 126, 127. As a youngster, Penry was in and out of a number of state schools and hospitals, until his father removed him from state schools altogether when he was 12. Id. at 120. Penry's aunt subsequently struggled for over a year to teach Penry how to print his name. Id. at 133.
The State introduced the testimony of two psychiatrists to rebut the testimony of Dr. Garcia. Dr. Kenneth Vogtsberger testified that, although Penry was a person of limited mental ability, he was not suffering from any mental illness or defect at the time of the crime, and that he knew the difference between right and wrong and had the potential to honor the law. Id. at 144-145. In his view, Penry had characteristics consistent with an antisocial personality, including an inability to learn from experience and a tendency to be impulsive and to violate society's norms. Id. at 149-150. He testified further that Penry's low IQ scores underestimated his alertness and understanding of what went on around him. Id. at 146.
Dr. Felix Peebles also testified for the State that Penry was legally sane at the time of the offense, and had a "full-blown anti-social personality." Id. at 171. In addition, Dr. Peebles testified that he personally diagnosed Penry as being mentally retarded in 1973 and again in 1977, and that Penry "had a very bad life generally, bringing up." Id. at 168-169. In Dr. Peebles' view, Penry "had been socially and emotionally deprived, and he had not learned to read and write adequately." Id. at 169. Although they disagreed with the defense psychiatrist over the extent and cause of Penry's mental limitations, both psychiatrists for the State acknowledged that Penry was a person of extremely limited mental ability, and that he seemed unable to learn from his mistakes. Id. at 149, 172-173.
The jury rejected Penry's insanity defense, and found him guilty of capital murder. Tex.Penal Code Ann. §19.03 (1974 and Supp. 1989). The following day, at the close of the penalty hearing, the jury decided the sentence to be imposed on Penry by answering three "special issues":
(1) whether the conduct of the defendant that caused the death of the deceased was committed deliberately and with the reasonable expectation that the death of the deceased or another would result;
(2) whether there is a probability that the defendant would commit criminal acts of violence that would constitute a continuing threat to society; and
(3) if raised by the evidence, whether the conduct of the defendant in killing the deceased was unreasonable in response to the provocation, if any, by the deceased.
Tex.Code Crim.Proc.Ann., Art. 37.071(b) (Vernon 1981 and Supp. 1989). If the jury unanimously answers "yes" to each issue submitted, the trial court must sentence the defendant to death. Art. 37.071(c)-(e). Otherwise, the defendant is sentenced to life imprisonment. Ibid.
Defense counsel raised a number of objections to the proposed charge to the jury. With respect to the first special issue, he objected that the charge failed to define the term "deliberately." App. 210. With respect to the second special issue, he objected that the charge failed to define the terms "probability," "criminal acts of violence," and "continuing threat to society." Id. at 210-211. Defense counsel also objected to the charge because it failed to "authorize a discretionary grant of mercy based upon the existence of mitigating circumstances" and because it
fail[ed] to require as a condition to the assessment of the death penalty that the State show beyond a reasonable doubt that any aggravating circumstances found to exist outweigh any mitigating circumstances.
Id. at 211. In addition, the charge failed to instruct the jury that it may take into consideration all of the evidence whether aggravating or mitigating in nature which was submitted in the full trial of the case. Id. at 212. Defense counsel also objected that, in light of Penry's mental retardation, permitting the jury to assess the death penalty in this case amounted to cruel and unusual punishment prohibited by the Eighth Amendment. Id. at 211.
These objections were overruled by the trial court. The jury was then instructed that the State bore the burden of proof on the special issues, and that, before any issue could be answered "yes," all twelve jurors must be convinced by the evidence beyond a reasonable doubt that the answer to that issue should be "yes." Id. at 25. The jurors were further instructed that, in answering the three special issues, they could consider all the evidence submitted in both the guilt-innocence phase and the penalty phase of the trial. Id. at 26. The jury charge then listed the three questions, with the names of the defendant and the deceased inserted.
The jury answered "yes" to all three special issues, and Penry was sentenced to death. The Texas Court of Criminal Appeals affirmed his conviction and sentence on direct appeal. Penry v. State, 691 S. W. 2d 636 (Tex. Crim.App. 1985). That court held that terms such as "deliberately," "probability," and "continuing threat to society" used in the special issues need not be defined in the jury charge, because the jury would know their common meaning. Id. at 653-654. The court concluded that Penry was allowed to present all relevant mitigating evidence at the punishment hearing, and that there was no constitutional infirmity in failing to require the jury to find that aggravating circumstances outweighed mitigating ones or in failing to authorize a discretionary grant of mercy based upon the existence of mitigating circumstances. Id. at 654. The court also held that imposition of the death penalty was not prohibited by virtue of Penry's mental retardation. Id. at 654-655. This Court denied certiorari on direct review. Sub nom. Penry v. Texas, 474 U. S. 1073 (1986).
Penry then filed this federal habeas corpus petition challenging his death sentence. Among other claims, Penry argued that he was sentenced in violation of the Eighth Amendment because the trial court failed to instruct the jury on how to weigh mitigating factors in answering the special issues, and failed to define the term "deliberately." Penry also argued that it was cruel and unusual punishment to execute a mentally retarded person. The District Court denied relief, App. 234-273, and Penry appealed to the Court of Appeals for the Fifth Circuit.
The Court of Appeals affirmed the District Court's judgment. 832 F. 2d 915 (1987). The court stressed, however, that it found considerable merit in Penry's claim that the jury was not allowed to consider and apply all of his personal mitigating circumstances in answering the Texas special issues. Although the jury was presented with evidence that might mitigate Penry's personal culpability for the crime, such as his mental retardation, arrested emotional development, and abused background, the jury could not give effect to that evidence by mitigating Penry's sentence to life imprisonment. "Having said that it was a deliberate murder and that Penry will be a continuing threat, the jury can say no more." Id. at 920. In short, the court did not see how Penry's mitigating evidence, under the instructions given, could be fully acted upon by the jury, because "[t]here is no place for the jury to say no' to the death penalty" based on the mitigating force of those circumstances. Id. at 925. Although the court questioned whether Penry was given the individualized sentencing that the Constitution requires, it ultimately concluded that prior Circuit decisions required it to reject Penry's claims. Id. at 926. The court also rejected Penry's contention that it was cruel and unusual punishment to execute a mentally retarded person such as himself. Id. at 918 (citing Brogdon v. Butler, 824 F. 2d 338, 341 (CA5 1987)).
We granted certiorari to resolve two questions. 487 U.S. 1233 (1988). First, was Penry sentenced to death in violation of the Eighth Amendment because the jury was not adequately instructed to take into consideration all of his mitigating evidence and because the terms in the Texas special issues were not defined in such a way that the jury could consider and give effect to his mitigating evidence in answering them? Second, is it cruel and unusual punishment under the Eighth Amendment to execute a mentally retarded person with Penry's reasoning ability?
II
A
Penry is currently before the Court on his petition in federal court for a writ of habeas corpus. Because Penry is before us on collateral review, we must determine, as a threshold matter, whether granting him the relief he seeks would create a "new rule." Teague v. Lane, 489 U. S. 288, 489 U. S. 301 (1989). Under Teague, new rules will not be applied or announced in cases on collateral review unless they fall into one of two exceptions. Id. at 489 U. S. 311 -313.
Teague was not a capital case, and the plurality opinion expressed no views regarding how the retroactivity approach adopted in Teague would be applied in the capital sentencing context. Id. at 489 U. S. 314, n. 2. The plurality noted, however, that a criminal judgment necessarily includes the sentence imposed, and that collateral challenges to sentences
delay the enforcement of the judgment at issue and decrease the possibility that 'there will at some point be the certainty that comes with an end to litigation.'
Ibid. (quoting Sanders v. United States, 373 U. S. 1, 373 U. S. 25 (1963) (Harlan, J., dissenting)). See also Mackey v. United States, 401 U. S. 667, 401 U. S. 690 -695 (1971) (Harlan, J., concurring in judgments in part and dissenting in part). In our view, the finality concerns underlying Justice Harlan's approach to retroactivity are applicable in the capital sentencing context, as are the two exceptions to his general rule of nonretroactivity. See Teague, supra, at 489 U. S. 311 -313.
B
As we indicated in Teague,
[i]n general… a case announces a new rule when it breaks new ground or imposes a new obligation on the States or the Federal Government.
489 U.S. at 489 U. S. 301. Or,
[t]o put it differently, a case announces a new rule if the result was not dictated by precedent existing at the time the defendant's conviction became final.
Ibid. (emphasis in original). Teague noted that "[i]t is admittedly often difficult to determine when a case announces a new rule." Ibid. Justice Harlan recognized
"the inevitable difficulties that will arise in attempting "to determine whether a particular decision has really announced a new' rule at all, or whether it has simply applied a well-established constitutional principle to govern a case which is closely analogous to those which have been previously considered in the prior case law.""
Mackey, supra, at 401 U. S. 695 (opinion concurring in judgments in part and dissenting in part) (quoting Desist v. United States, 394 U. S. 244, 394 U. S. 263 (1969) (Harlan, J., dissenting)). See generally Yates v. Aiken, 484 U. S. 211, 484 U. S. 216 -217 (1988) (concluding that Francis v. Franklin, 471 U. S. 307 (1985), did not announce a new rule, but was "merely an application of the principle that governed our decision in Sandstrom v. Montana, [442 U.S. 510 (1979),] which had been decided before petitioner's trial took place").
Penry's conviction became final on January 13, 1986, when this Court denied his petition for certiorari on direct review of his conviction and sentence. Sub nom. Penry v. Texas, supra. This Court's decisions in Lockett v. Ohio, 438 U.S. 586 (1978), and Eddings v. Oklahoma, 455 U. S. 104 (1982), were rendered before his conviction became final. Under the retroactivity principles adopted in Griffith v. Kentucky, 479 U. S. 314 (1987), Penry is entitled to the benefit of those decisions. Citing Lockett and Eddings, Penry argues that he was sentenced to death in violation of the Eighth Amendment because, in light of the jury instructions given, the jury was unable to fully consider and give effect to the mitigating evidence of his mental retardation and abused background, which he offered as the basis for a sentence less than death. Penry thus seeks a rule that, when such mitigating evidence is presented, Texas juries must, upon request, be given jury instructions that make it possible for them to give effect to that mitigating evidence in determining whether a defendant should be sentenced to death. We conclude, for the reasons discussed below, that the rule Penry seeks is not a "new rule" under Teague.
Penry does not challenge the facial validity of the Texas death penalty statute, which was upheld against an Eighth Amendment challenge in Jurek v. Texas, 428 U. S. 262 (1976). Nor does he dispute that some types of mitigating evidence can be fully considered by the sentencer in the absence of special jury instructions. See Franklin v. Lynaugh, 487 U. S. 164, 487 U. S. 175 (1988) (plurality opinion); id. at 487 U. S. 185 -186 (O'CONNOR, J., concurring in judgment). Instead, Penry argues that, on the facts of this case, the jury was unable to fully consider and give effect to the mitigating evidence of his mental retardation and abused background in answering the three special issues. In our view, the relief Penry seeks does not "impos[e] a new obligation" on the State of Texas. Teague, supra, at 489 U. S. 301. Rather, Penry simply asks the State to fulfill the assurance upon which Jurek was based: namely, that the special issues would be interpreted broadly enough to permit the sentencer to consider all of the relevant mitigating evidence a defendant might present in imposing sentence.
In Jurek, the joint opinion of Justices Stewart, Powell, and STEVENS noted that the Texas statute narrowed the circumstances in which the death penalty could be imposed to five categories of murders. 428 U.S. at 428 U. S. 268. Thus, although Texas had not adopted a list of statutory aggravating factors that the jury must find before imposing the death penalty, "its action in narrowing the categories of murders for which a death sentence may ever be imposed serves much the same purpose," id. at 428 U. S. 270, and effectively "requires the sentencing authority to focus on the particularized nature of the crime." Id. at 428 U. S. 271. To provide the individualized sentencing determination required by the Eighth Amendment, however, the sentencer must be allowed to consider mitigating evidence. Ibid. Indeed, as Woodson v. North Carolina, 428 U. S. 280 (1976), made clear,
in capital cases, the fundamental respect for humanity underlying the Eighth Amendment… requires consideration of the character and record of the individual offender and the circumstances of the particular offense as a constitutionally indispensable part of the process of inflicting the penalty of death.
Id. at 428 U. S. 304 (plurality opinion).
Because the Texas death penalty statute does not explicitly mention mitigating circumstances, but rather directs the jury to answer three questions, Jurek reasoned that the statute's constitutionality "turns on whether the enumerated questions allow consideration of particularized mitigating factors." 428 U.S. at 428 U. S. 272. Although the various terms in the special questions had yet to be defined, the joint opinion concluded that the sentencing scheme satisfied the Eighth Amendment on the assurance that the Texas Court of Criminal Appeals would interpret the question concerning future dangerousness so as to allow the jury to consider whatever mitigating circumstances a defendant may be able to show, including a defendant's prior criminal record, age, and mental or emotional state. Id. at 428 U. S. 272 -273.
Our decisions subsequent to Jurek have reaffirmed that the Eighth Amendment mandates an individualized assessment of the appropriateness of the death penalty. In Lockett v. Ohio, 438 U. S. 586 (1978), a plurality of this Court held that the Eighth and Fourteenth Amendments require that the sentencer
not be precluded from considering, as a mitigating factor, any aspect of a defendant's character or record and any of the circumstances of the offense that the defendant proffers as a basis for a sentence less than death.
Id. at 438 U. S. 604 (emphasis in original). Thus, the Court held unconstitutional the Ohio death penalty statute which mandated capital punishment upon a finding of one aggravating circumstance unless one of three statutory mitigating factors was present.
Lockett underscored Jurek's recognition that the constitutionality of the Texas scheme "turns on whether the enumerated questions allow consideration of particularized mitigating factors." Jurek, 428 U.S. at 428 U. S. 272. The plurality opinion in Lockett indicated that the Texas death penalty statute had
survived the petitioner's Eighth and Fourteenth Amendment attack [in Jurek ] because three Justices concluded that the Texas Court of Criminal Appeals had broadly interpreted the second question -despite its facial narrowness -so as to permit the sentencer to consider 'whatever mitigating circumstances' the defendant might be able to show.
438 U.S. at 438 U. S. 607. Thus, the Lockett plurality noted that neither the Texas statute upheld in 1976 nor the statutes that had survived facial challenges in Gregg v. Georgia, 428 U. S. 153 (1976), and Proffitt v. Florida, 428 U. S. 242 (1976),
clearly operated at that time to prevent the sentencer from considering any aspect of the defendant's character and record or any circumstances of his offense as an independently mitigating factor.
Lockett, supra, at 438 U. S. 607. Cf. Hitchcock v. Dugger, 481 U. S. 393 (1987) (sustaining "as applied" challenge to Florida death penalty statute); Godfrey v. Georgia, 446 U. S. 420 (1980) (sustaining "as applied" challenge to Georgia death penalty statute).
In Eddings v. Oklahoma, 455 U. S. 104 (1982), a majority of the Court reaffirmed that a sentencer may not be precluded from considering, and may not refuse to consider, any relevant mitigating evidence offered by the defendant as the basis for a sentence less than death. In Eddings, the Oklahoma death penalty statute permitted the defendant to introduce evidence of any mitigating circumstance, but the sentencing judge concluded, as a matter of law, that he was unable to consider mitigating evidence of the youthful defendant's troubled family history, beatings by a harsh father, and emotional disturbance. Applying Lockett, we held that
[j]ust as the State may not by statute preclude the sentencer from considering any mitigating factor, neither may the sentencer refuse to consider, as a matter of law, any relevant mitigating evidence.
455 U.S. at 455 U. S. 113 -114 (emphasis in original). In that case, "it was as if the trial judge had instructed a jury to disregard the mitigating evidence [the defendant] proffered on his behalf." Id. at 114.
Thus, at the time Penry's conviction became final, it was clear from Lockett and Eddings that a State could not, consistent with the Eighth and Fourteenth Amendments, prevent the sentencer from considering and giving effect to evidence relevant to the defendant's background or character or to the circumstances of the offense that mitigate against imposing the death penalty. Moreover, the facial validity of the Texas death penalty statute had been upheld in Jurek on the basis of assurances that the special issues would be interpreted broadly enough to enable sentencing juries to consider all of the relevant mitigating evidence a defendant might present. Penry argues that those assurances were not fulfilled in his particular case because, without appropriate instructions, the jury could not fully consider and give effect to the mitigating evidence of his mental retardation and abused childhood in rendering its sentencing decision. The rule Penry seeks -that when such mitigating evidence is presented, Texas juries must, upon request, be given jury instructions that make it possible for them to give effect to that mitigating evidence in determining whether the death penalty should be imposed -is not a "new rule" under Teague, because it is dictated by Eddings and Lockett. Moreover, in light of the assurances upon which Jurek was based, we conclude that the relief Penry seeks does not "impos[e] a new obligation" on the State of Texas. Teague, 489 U.S. at 489 U. S. 301.
Underlying Lockett and Eddings is the principle that punishment should be directly related to the personal culpability of the criminal defendant. If the sentencer is to make an individualized assessment of the appropriateness of the death penalty,
evidence about the defendant's background and character is relevant because of the belief, long held by this society, that defendants who commit criminal acts that are attributable to a disadvantaged background, or to emotional and mental problems, may be less culpable than defendants who have no such excuse.
California v. Brown, 479 U. S. 538, 479 U. S. 545 (1987) (O'CONNOR, J., concurring). Moreover, Eddings makes clear that it is not enough simply to allow the defendant to present mitigating evidence to the sentencer. The sentencer must also be able to consider and give effect to that evidence in imposing sentence. Hitchcock v. Dugger, 481 U. S. 393 (1987). Only then can we be sure that the sentencer has treated the defendant as a "uniquely individual human bein[g]," and has made a reliable determination that death is the appropriate sentence. Woodson, 428 U.S. at 428 U. S. 304, 428 U. S. 305.
Thus, the sentence imposed at the penalty stage should reflect a reasoned moral response to the defendant's background, character, and crime.
California v. Brown, supra, at 479 U. S. 545 (O'CONNOR, J., concurring) (emphasis in original).
Although Penry offered mitigating evidence of his mental retardation and abused childhood as the basis for a sentence of life imprisonment rather than death, the jury that sentenced him was only able to express its views on the appropriate sentence by answering three questions: Did Penry act deliberately when he murdered Pamela Carpenter? Is there a probability that he will be dangerous in the future? Did he act unreasonably in response to provocation? The jury was never instructed that it could consider the evidence offered by Penry as mitigating evidence, and that it could give mitigating effect to that evidence in imposing sentence.
Like the petitioner in Franklin v. Lynaugh,, Penry contends that, in the absence of his requested jury instructions, the Texas death penalty statute was applied in an unconstitutional manner by precluding the jury from acting upon the particular mitigating evidence he introduced. Franklin was the first case considered by this Court since Jurek to address a claim concerning the treatment of mitigating evidence under the Texas special issues. Like Jurek itself, Franklin did not produce a majority opinion for the Court. The Franklin plurality, and the two concurring Justices, concluded that Franklin was not sentenced to death in violation of the Eighth Amendment because the jury was free to give effect to his mitigating evidence of good behavior in prison by answering "no" to the question on future dangerousness. 487 U.S. at 487 U. S. 177 (plurality opinion); id. at 487 U. S. 185 (O'CONNOR, J., concurring in judgment). Moreover, a majority agreed that "residual doub[t]" as to Franklin's guilt was not a constitutionally mandated mitigating factor. Id. at 487 U. S. 173, and n. 6 (plurality opinion); id. at 487 U. S. 187 -188 (O'CONNOR, J., concurring in judgment).
In Franklin, however, the five concurring and dissenting Justices did not share the plurality's categorical reading of Jurek. In the plurality's view, Jurek had expressly and unconditionally upheld the manner in which mitigating evidence is considered under the special issues. Id. at 487 U. S. 179 -180, and n. 10. In contrast, five Members of the Court read Jurek as not precluding a claim that, in a particular case, the jury was unable to fully consider the mitigating evidence introduced by a defendant in answering the special issues. Id. at 487 U. S. 183 (O'CONNOR, J., concurring in judgment); id. at 487 U. S. 199 -200 (STEVENS, J., dissenting). Indeed, both the concurrence and the dissent understood Jurek as resting fundamentally on the express assurance that the special issues would permit the jury to fully consider all the mitigating evidence a defendant introduced that was relevant to the defendant's background and character and to the circumstances of the offense. Moreover, both the concurrence and the dissent stressed that
the right to have the sentencer consider and weigh relevant mitigating evidence would be meaningless unless the sentencer was also permitted to give effect to its consideration
in imposing sentence. Id. at 487 U. S. 185 (O'CONNOR, J., concurring in judgment); id. at 487 U. S. 199 (STEVENS, J., dissenting).
The concurrence in Franklin concluded that there was no Eighth Amendment violation in that case because Franklin's evidence of his good prison behavior had no clear relevance to his character other than to demonstrate his ability to live in a highly structured prison environment without endangering others. Thus, the jury was able to give effect to the mitigating force of this evidence in answering the second special issue. The concurrence noted, however:
If… petitioner had introduced mitigating evidence about his background or character or the circumstances of the crime that was not relevant to the special verdict questions, or that had relevance to the defendant's moral culpability beyond the scope of the special verdict questions, the jury instructions would have provided the jury with no vehicle for expressing its 'reasoned moral response' to that evidence. If this were such a case, then we would have to decide whether the jury's inability to give effect to that evidence amounted to an Eighth Amendment violation.
Id. at 487 U. S. 185.
Penry argues that his mitigating evidence of mental retardation and childhood abuse has relevance to his moral culpability beyond the scope of the special issues, and that the jury was unable to express its "reasoned moral response" to that evidence in determining whether death was the appropriate punishment. We agree. Thus, we reject the State's contrary argument that the jury was able to consider and give effect to all of Penry's mitigating evidence in answering the special issues without any jury instructions on mitigating evidence.
The first special issue asks whether the defendant acted "deliberately and with the reasonable expectation that the death of the deceased… would result." Neither the Texas Legislature nor the Texas Court of Criminal Appeals have defined the term "deliberately," and the jury was not instructed on the term, so we do not know precisely what meaning the jury gave to it. Assuming, however, that the jurors in this case understood "deliberately" to mean something more than that Penry was guilty of "intentionally" committing murder, those jurors may still have been unable to give effect to Penry's mitigating evidence in answering the first special issue.
Penry's mental retardation was relevant to the question whether he was capable of acting "deliberately," but it also "had relevance to [his] moral culpab