Justice Stevens delivered the opinion of the Court.

Those mentally retarded persons who meet the law's requirements for criminal responsibility should be tried and punished when they commit crimes. Because of their disabilities in areas of reasoning, judgment, and control of their impulses, however, they do not act with the level of moral culpability that characterizes the most serious adult criminal conduct. Moreover, their impairments can jeopardize the reliability and fairness of capital proceedings against mentally retarded defendants. Presumably for these reasons, in the 13 years since we decided Penry v. Lynaugh, 492 U. S. 302 (1989), the American public, legislators, scholars, and judges have deliberated over the question whether the death penalty should ever be imposed on a mentally retarded criminal. The consensus reflected in those deliberations informs our answer to the question presented by this case: whether such executions are "cruel and unusual punishments" prohibited by the Eighth Amendment to the Federal Constitution.

I

Petitioner, Daryl Renard Atkins, was convicted of abduction, armed robbery, and capital murder, and sentenced to death. At approximately midnight on August 16, 1996, Atkins and William Jones, armed with a semiautomatic handgun, abducted Eric Nesbitt, robbed him of the money on his person, drove him to an automated teller machine in his pickup truck where cameras recorded their withdrawal of additional cash, then took him to an isolated location where he was shot eight times and killed.

Jones and Atkins both testified in the guilt phase of Atkins' trial.1 Each confirmed most of the details in the other's account of the incident, with the important exception that each stated that the other had actually shot and killed Nesbitt. Jones' testimony, which was both more coherent and credible than Atkins', was obviously credited by the jury and was sufficient to establish Atkins' guilt.2 At the penalty phase of the trial, the State introduced victim impact evidence and proved two aggravating circumstances: future dangerousness and "vileness of the offense." To prove future dangerousness, the State relied on Atkins' prior felony convictions as well as the testimony of four victims of earlier robberies and assaults. To prove the second aggravator, the prosecution relied upon the trial record, including pictures of the deceased's body and the autopsy report.

In the penalty phase, the defense relied on one witness, Dr. Evan Nelson, a forensic psychologist who had evaluated Atkins before trial and concluded that he was "mildly mentally retarded."3 His conclusion was based on interviews with people who knew Atkins,4 a review of school and court records, and the administration of a standard intelligence test which indicated that Atkins had a full scale IQ of 59.5

The jury sentenced Atkins to death, but the Virginia Supreme Court ordered a second sentencing hearing because the trial court had used a misleading verdict form. 257 Va. 160, 510 S. E. 2d 445 (1999). At the resentencing, Dr. Nelson again testified. The State presented an expert rebuttal witness, Dr. Stanton Samenow, who expressed the opinion that Atkins was not mentally retarded, but rather was of "average intelligence, at least," and diagnosable as having antisocial personality disorder.6 App. 476. The jury again sentenced Atkins to death.

The Supreme Court of Virginia affirmed the imposition of the death penalty. 260 Va. 375, 385, 534 S. E. 2d 312, 318 (2000). Atkins did not argue before the Virginia Supreme Court that his sentence was disproportionate to penalties imposed for similar crimes in Virginia, but he did contend "that he is mentally retarded and thus cannot be sentenced to death." Id., at 386, 534 S. E. 2d, at 318. The majority of the state court rejected this contention, relying on our holding in Penry. 260 Va., at 387, 534 S. E. 2d, at 319. The Court was "not willing to commute Atkins' sentence of death to life imprisonment merely because of his IQ score." Id., at 390, 534 S. E. 2d, at 321.

Justice Hassell and Justice Koontz dissented. They rejected Dr. Samenow's opinion that Atkins possesses average intelligence as "incredulous as a matter of law," and concluded that "the imposition of the sentence of death upon a criminal defendant who has the mental age of a child between the ages of 9 and 12 is excessive." Id., at 394, 395-396, 534 S. E. 2d, at 323-324. In their opinion, "it is indefensible to conclude that individuals who are mentally retarded are not to some degree less culpable for their criminal acts. By definition, such individuals have substantial limitations not shared by the general population. A moral and civilized society diminishes itself if its system of justice does not afford recognition and consideration of those limitations in a meaningful way." Id., at 397, 534 S. E. 2d, at 325.

Because of the gravity of the concerns expressed by the dissenters, and in light of the dramatic shift in the state legislative landscape that has occurred in the past 13 years, we granted certiorari to revisit the issue that we first addressed in the Penry case. 533 U. S. 976 (2001).

II

The Eighth Amendment succinctly prohibits "excessive" sanctions. It provides: "Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted." In Weems v. United States, 217 U. S. 349 (1910), we held that a punishment of 12 years jailed in irons at hard and painful labor for the crime of falsifying records was excessive. We explained "that it is a precept of justice that punishment for crime should be graduated and proportioned to the offense." Id., at 367. We have repeatedly applied this proportionality precept in later cases interpreting the Eighth Amendment. See Harmelin v. Michigan, 501 U. S. 957, 997-998 (1991) (Kennedy, J., concurring in part and concurring in judgment); see also id., at 1009-1011 (White, J., dissenting).7 Thus, even though "imprisonment for ninety days is not, in the abstract, a punishment which is either cruel or unusual," it may not be imposed as a penalty for "the `status' of narcotic addiction," Robinson v. California, 370 U. S. 660, 666-667 (1962), because such a sanction would be excessive. As Justice Stewart explained in Robinson: "Even one day in prison would be a cruel and unusual punishment for the `crime' of having a common cold." Id., at 667.

A claim that punishment is excessive is judged not by the standards that prevailed in 1685 when Lord Jeffreys presided over the "Bloody Assizes" or when the Bill of Rights was adopted, but rather by those that currently prevail. As Chief Justice Warren explained in his opinion in Trop v. Dulles, 356 U. S. 86 (1958): "The basic concept underlying the Eighth Amendment is nothing less than the dignity of man. ... The Amendment must draw its meaning from the evolving standards of decency that mark the progress of a maturing society." Id., at 100-101.

Proportionality review under those evolving standards should be informed by " `objective factors to the maximum possible extent,' " see Harmelin, 501 U. S., at 1000 (quoting Rummel v. Estelle, 445 U. S 263, 274-275 (1980)). We have pinpointed that the "clearest and most reliable objective evidence of contemporary values is the legislation enacted by the country's legislatures." Penry, 492 U. S., at 331. Relying in part on such legislative evidence, we have held that death is an impermissibly excessive punishment for the rape of an adult woman, Coker v. Georgia, 433 U. S. 584, 593-596 (1977), or for a defendant who neither took life, attempted to take life, nor intended to take life, Enmund v. Florida, 458 U. S. 782, 789-793 (1982). In Coker, we focused primarily on the then-recent legislation that had been enacted in response to our decision 10 years earlier in Furman v. Georgia, 408 U. S. 238 (1972) (per curiam), to support the conclusion that the "current judgment," though "not wholly unanimous," weighed very heavily on the side of rejecting capital punishment as a "suitable penalty for raping an adult woman." Coker, 433 U. S., at 596. The "current legislative judgment" relevant to our decision in Enmund was less clear than in Coker but "nevertheless weigh[ed] on the side of rejecting capital punishment for the crime at issue." Enmund, 458 U. S., at 793.

We also acknowledged in Coker that the objective evidence, though of great importance, did not "wholly determine" the controversy, "for the Constitution contemplates that in the end our own judgment will be brought to bear on the question of the acceptability of the death penalty under the Eighth Amendment." 433 U. S., at 597. For example, in Enmund, we concluded by expressing our own judgment about the issue:

"For purposes of imposing the death penalty, Enmund's criminal culpability must be limited to his participation in the robbery, and his punishment must be tailored to his personal responsibility and moral guilt. Putting Enmund to death to avenge two killings that he did not commit and had no intention of committing or causing does not measurably contribute to the retributive end of ensuring that the criminal gets his just deserts. This is the judgment of most of the legislatures that have recently addressed the matter, and we have no reason to disagree with that judgment for purposes of construing and applying the Eighth Amendment." 458 U. S., at 801 (emphasis added).

Thus, in cases involving a consensus, our own judgment is "brought to bear," Coker, 433 U. S., at 597, by asking whether there is reason to disagree with the judgment reached by the citizenry and its legislators.

Guided by our approach in these cases, we shall first review the judgment of legislatures that have addressed the suitability of imposing the death penalty on the mentally retarded and then consider reasons for agreeing or disagreeing with their judgment.

III

The parties have not called our attention to any state legislative consideration of the suitability of imposing the death penalty on mentally retarded offenders prior to 1986. In that year, the public reaction to the execution of a mentally retarded murderer in Georgia8 apparently led to the enactment of the first state statute prohibiting such executions.9 In 1988, when Congress enacted legislation reinstating the federal death penalty, it expressly provided that a "sentence of death shall not be carried out upon a person who is mentally retarded."10 In 1989, Maryland enacted a similar prohibition.11 It was in that year that we decided Penry, and concluded that those two state enactments, "even when added to the 14 States that have rejected capital punishment completely, do not provide sufficient evidence at present of a national consensus." 492 U. S., at 334.

Much has changed since then. Responding to the national attention received by the Bowden execution and our decision in Penry, state legislatures across the country began to address the issue. In 1990 Kentucky and Tennessee enacted statutes similar to those in Georgia and Maryland, as did New Mexico in 1991, and Arkansas, Colorado, Washington, Indiana, and Kansas in 1993 and 1994.12 In 1995, when New York reinstated its death penalty, it emulated the Federal Government by expressly exempting the mentally retarded.13 Nebraska followed suit in 1998.14 There appear to have been no similar enactments during the next two years, but in 2000 and 2001 six more States--South Dakota, Arizona, Connecticut, Florida, Missouri, and North Carolina--joined the procession.15 The Texas Legislature unanimously adopted a similar bill,16 and bills have passed at least one house in other States, including Virginia and Nevada.17

It is not so much the number of these States that is significant, but the consistency of the direction of change.18 Given the well-known fact that anticrime legislation is far more popular than legislation providing protections for persons guilty of violent crime, the large number of States prohibiting the execution of mentally retarded persons (and the complete absence of States passing legislation reinstating the power to conduct such executions) provides powerful evidence that today our society views mentally retarded offenders as categorically less culpable than the average criminal. The evidence carries even greater force when it is noted that the legislatures that have addressed the issue have voted overwhelmingly in favor of the prohibition.19 Moreover, even in those States that allow the execution of mentally retarded offenders, the practice is uncommon. Some States, for example New Hampshire and New Jersey, continue to authorize executions, but none have been carried out in decades. Thus there is little need to pursue legislation barring the execution of the mentally retarded in those States. And it appears that even among those States that regularly execute offenders and that have no prohibition with regard to the mentally retarded, only five have executed offenders possessing a known IQ less than 70 since we decided Penry.20 The practice, therefore, has become truly unusual, and it is fair to say that a national consensus has developed against it.21

To the extent there is serious disagreement about the execution of mentally retarded offenders, it is in determining which offenders are in fact retarded. In this case, for instance, the Commonwealth of Virginia disputes that Atkins suffers from mental retardation. Not all people who claim to be mentally retarded will be so impaired as to fall within the range of mentally retarded offenders about whom there is a national consensus. As was our approach in Ford v. Wainwright, with regard to insanity, "we leave to the State[s] the task of developing appropriate ways to enforce the constitutional restriction upon its execution of sentences." 477 U. S. 399, 405, 416-417 (1986).22

IV

This consensus unquestionably reflects widespread judgment about the relative culpability of mentally retarded offenders, and the relationship between mental retardation and the penological purposes served by the death penalty. Additionally, it suggests that some characteristics of mental retardation undermine the strength of the procedural protections that our capital jurisprudence steadfastly guards.

As discussed above, clinical definitions of mental retardation require not only subaverage intellectual functioning, but also significant limitations in adaptive skills such as communication, self-care, and self-direction that became manifest before age 18. Mentally retarded persons frequently know the difference between right and wrong and are competent to stand trial. Because of their impairments, however, by definition they have diminished capacities to understand and process information, to communicate, to abstract from mistakes and learn from experience, to engage in logical reasoning, to control impulses, and to understand the reactions of others.23 There is no evidence that they are more likely to engage in criminal conduct than others, but there is abundant evidence that they often act on impulse rather than pursuant to a premeditated plan, and that in group settings they are followers rather than leaders.24 Their deficiencies do not warrant an exemption from criminal sanctions, but they do diminish their personal culpability.

In light of these deficiencies, our death penalty jurisprudence provides two reasons consistent with the legislative consensus that the mentally retarded should be categorically excluded from execution. First, there is a serious question as to whether either justification that we have recognized as a basis for the death penalty applies to mentally retarded offenders. Gregg v. Georgia, 428 U. S. 153, 183 (1976), identified "retribution and deterrence of capital crimes by prospective offenders" as the social purposes served by the death penalty. Unless the imposition of the death penalty on a mentally retarded person "measurably contributes to one or both of these goals, it `is nothing more than the purposeless and needless imposition of pain and suffering,' and hence an unconstitutional punishment." Enmund, 458 U. S., at 798.

With respect to retribution--the interest in seeing that the offender gets his "just deserts"--the severity of the appropriate punishment necessarily depends on the culpability of the offender. Since Gregg, our jurisprudence has consistently confined the imposition of the death penalty to a narrow category of the most serious crimes. For example, in Atkins v. Virginiafrey v. Georgia, 446 U. S. 420 (1980), we set aside a death sentence because the petitioner's crimes did not reflect "a consciousness materially more `depraved' than that of any person guilty of murder." Id., at 433. If the culpability of the average murderer is insufficient to justify the most extreme sanction available to the State, the lesser culpability of the mentally retarded offender surely does not merit that form of retribution. Thus, pursuant to our narrowing jurisprudence, which seeks to ensure that only the most deserving of execution are put to death, an exclusion for the mentally retarded is appropriate.

With respect to deterrence--the interest in preventing capital crimes by prospective offenders--"it seems likely that `capital punishment can serve as a deterrent only when murder is the result of premeditation and deliberation,' " Enmund, 458 U. S., at 799. Exempting the mentally retarded from that punishment will not affect the "cold calculus that precedes the decision" of other potential murderers. Gregg, 428 U. S., at 186. Indeed, that sort of calculus is at the opposite end of the spectrum from behavior of mentally retarded offenders. The theory of deterrence in capital sentencing is predicated upon the notion that the increased severity of the punishment will inhibit criminal actors from carrying out murderous conduct. Yet it is the same cognitive and behavioral impairments that make these defendants less morally culpable--for example, the diminished ability to understand and process information, to learn from experience, to engage in logical reasoning, or to control impulses--that also make it less likely that they can process the information of the possibility of execution as a penalty and, as a result, control their conduct based upon that information. Nor will exempting the mentally retarded from execution lessen the deterrent effect of the death penalty with respect to offenders who are not mentally retarded. Such individuals are unprotected by the exemption and will continue to face the threat of execution. Thus, executing the mentally retarded will not measurably further the goal of deterrence.

The reduced capacity of mentally retarded offenders provides a second justification for a categorical rule making such offenders ineligible for the death penalty. The risk "that the death penalty will be imposed in spite of factors which may call for a less severe penalty," Lockett v. Ohio, 438 U. S. 586, 605 (1978), is enhanced, not only by the possibility of false confessions,25 but also by the lesser ability of mentally retarded defendants to make a persuasive showing of mitigation in the face of prosecutorial evidence of one or more aggravating factors. Mentally retarded defendants may be less able to give meaningful assistance to their counsel and are typically poor witnesses, and their demeanor may create an unwarranted impression of lack of remorse for their crimes. As Penry demonstrated, moreover, reliance on mental retardation as a mitigating factor can be a two-edged sword that may enhance the likelihood that the aggravating factor of future dangerousness will be found by the jury. 492 U. S., at 323-325. Mentally retarded defendants in the aggregate face a special risk of wrongful execution.

Our independent evaluation of the issue reveals no reason to disagree with the judgment of "the legislatures that have recently addressed the matter" and concluded that death is not a suitable punishment for a mentally retarded criminal. We are not persuaded that the execution of mentally retarded criminals will measurably advance the deterrent or the retributive purpose of the death penalty. Construing and applying the Eighth Amendment in the light of our "evolving standards of decency," we therefore conclude that such punishment is excessive and that the Constitution "places a substantive restriction on the State's power to take the life" of a mentally retarded offender. Ford, 477 U. S., at 405.

The judgment of the Virginia Supreme Court is reversed and the case is remanded for further proceedings not inconsistent with this opinion.

It is so ordered.