[March 1, 2005]

    Justice Kennedy delivered the opinion of the Court.

    This case requires us to address, for the second time in a decade and a half, whether it is permissible under the Eighth and Fourteenth Amendments to the Constitution of the United States to execute a juvenile offender who was older than 15 but younger than 18 when he committed a capital crime. In Stanford v. Kentucky, 492 U.S. 361 (1989), a divided Court rejected the proposition that the Constitution bars capital punishment for juvenile offenders in this age group. We reconsider the question.


    At the age of 17, when he was still a junior in high school, Christopher Simmons, the respondent here, committed murder. About nine months later, after he had turned 18, he was tried and sentenced to death. There is little doubt that Simmons was the instigator of the crime. Before its commission Simmons said he wanted to murder someone. In chilling, callous terms he talked about his plan, discussing it for the most part with two friends, Charles Benjamin and John Tessmer, then aged 15 and 16 respectively. Simmons proposed to commit burglary and murder by breaking and entering, tying up a victim, and throwing the victim off a bridge. Simmons assured his friends they could “get away with it” because they were minors.

    The three met at about 2 a.m. on the night of the murder, but Tessmer left before the other two set out. (The State later charged Tessmer with conspiracy, but dropped the charge in exchange for his testimony against Simmons.) Simmons and Benjamin entered the home of the victim, Shirley Crook, after reaching through an open window and unlocking the back door. Simmons turned on a hallway light. Awakened, Mrs. Crook called out, “Who’s there?” In response Simmons entered Mrs. Crook’s bedroom, where he recognized her from a previous car accident involving them both. Simmons later admitted this confirmed his resolve to murder her.

    Using duct tape to cover her eyes and mouth and bind her hands, the two perpetrators put Mrs. Crook in her minivan and drove to a state park. They reinforced the bindings, covered her head with a towel, and walked her to a railroad trestle spanning the Meramec River. There they tied her hands and feet together with electrical wire, wrapped her whole face in duct tape and threw her from the bridge, drowning her in the waters below.

    By the afternoon of September 9, Steven Crook had returned home from an overnight trip, found his bedroom in disarray, and reported his wife missing. On the same afternoon fishermen recovered the victim’s body from the river. Simmons, meanwhile, was bragging about the killing, telling friends he had killed a woman “because the bitch seen my face.”

    The next day, after receiving information of Simmons’ involvement, police arrested him at his high school and took him to the police station in Fenton, Missouri. They read him his Miranda rights. Simmons waived his right to an attorney and agreed to answer questions. After less than two hours of interrogation, Simmons confessed to the murder and agreed to perform a videotaped reenactment at the crime scene.

    The State charged Simmons with burglary, kidnaping, stealing, and murder in the first degree. As Simmons was 17 at the time of the crime, he was outside the criminal jurisdiction of Missouri’s juvenile court system.  He was tried as an adult. At trial the State introduced Simmons’ confession and the videotaped reenactment of the crime, along with testimony that Simmons discussed the crime in advance and bragged about it later. The defense called no witnesses in the guilt phase. The jury having returned a verdict of murder, the trial proceeded to the penalty phase.

    The State sought the death penalty. As aggravating factors, the State submitted that the murder was committed for the purpose of receiving money; was committed for the purpose of avoiding, interfering with, or preventing lawful arrest of the defendant; and involved depravity of mind and was outrageously and wantonly vile, horrible, and inhuman. The State called Shirley Crook’s husband, daughter, and two sisters, who presented moving evidence of the devastation her death had brought to their lives.

    In mitigation Simmons’ attorneys first called an officer of the Missouri juvenile justice system, who testified that Simmons had no prior convictions and that no previous charges had been filed against him. Simmons’ mother, father, two younger half brothers, a neighbor, and a friend took the stand to tell the jurors of the close relationships they had formed with Simmons and to plead for mercy on his behalf. Simmons’ mother, in particular, testified to the responsibility Simmons demonstrated in taking care of his two younger half brothers and of his grandmother and to his capacity to show love for them.

    During closing arguments, both the prosecutor and defense counsel addressed Simmons’ age, which the trial judge had instructed the jurors they could consider as a mitigating factor. Defense counsel reminded the jurors that juveniles of Simmons’ age cannot drink, serve on juries, or even see certain movies, because “the legislatures have wisely decided that individuals of a certain age aren’t responsible enough.” Defense counsel argued that Simmons’ age should make “a huge difference to [the jurors] in deciding just exactly what sort of punishment to make.” In rebuttal, the prosecutor gave the following response: “Age, he says. Think about age. Seventeen years old. Isn’t that scary? Doesn’t that scare you? Mitigating? Quite the contrary I submit. Quite the contrary.”

    The jury recommended the death penalty after finding the State had proved each of the three aggravating factors submitted to it. Accepting the jury’s recommendation, the trial judge imposed the death penalty....

    After these proceedings in Simmons’ case had run their course, this Court held that the Eighth and Fourteenth Amendments prohibit the execution of a mentally retarded person. Atkins v. Virginia, 536 U.S. 304 (2002). Simmons filed a new petition for state postconviction relief, arguing that the reasoning of Atkins established that the Constitution prohibits the execution of a juvenile who was under 18 when the crime was committed.

    The Missouri Supreme Court agreed. It held that since Stanford, “a national consensus has developed against the execution of juvenile offenders, as demonstrated by the fact that eighteen states now bar such executions for juveniles, that twelve other states bar executions altogether, that no state has lowered its age of execution below 18 since Stanford, that five states have legislatively or by case law raised or established the minimum age at 18, and that the imposition of the juvenile death penalty has become truly unusual over the last decade.”

On this reasoning it set aside Simmons’ death sentence and resentenced him to “life imprisonment without eligibility for probation, parole, or release except by act of the Governor.” 

    We granted certiorari, 540 U.S. 1160 (2004), and now affirm.


    The Eighth Amendment provides: “Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.” The provision is applicable to the States through the Fourteenth Amendment....The Eighth Amendment guarantees individuals the right not to be subjected to excessive sanctions. The right flows from the basic “ ‘precept of justice that punishment for crime should be graduated and proportioned to [the] offense.’ ” By protecting even those convicted of heinous crimes, the Eighth Amendment reaffirms the duty of the government to respect the dignity of all persons.

    The prohibition against “cruel and unusual punishments,” like other expansive language in the Constitution, must be interpreted according to its text, by considering history, tradition, and precedent, and with due regard for its purpose and function in the constitutional design. To implement this framework we have established the propriety and affirmed the necessity of referring to “the evolving standards of decency that mark the progress of a maturing society” to determine which punishments are so disproportionate as to be cruel and unusual. Trop v. Dulles (1958)....

    In Thompson v. Oklahoma, 487 U.S. 815 (1988), a plurality of the Court determined that our standards of decency do not permit the execution of any offender under the age of 16 at the time of the crime.  The plurality opinion explained that no death penalty State that had given express consideration to a minimum age for the death penalty had set the age lower than 16. The plurality also observed that “[t]he conclusion that it would offend civilized standards of decency to execute a person who was less than 16 years old at the time of his or her offense is consistent with the views that have been expressed by respected professional organizations, by other nations that share our Anglo-American heritage, and by the leading members of the Western European community.” The opinion further noted that juries imposed the death penalty on offenders under 16 with exceeding rarity; the last execution of an offender for a crime committed under the age of 16 had been carried out in 1948, 40 years prior. 

    Bringing its independent judgment to bear on the permissibility of the death penalty for a 15-year-old offender, the Thompson plurality stressed that “[t]he reasons why juveniles are not trusted with the privileges and responsibilities of an adult also explain why their irresponsible conduct is not as morally reprehensible as that of an adult.” According to the plurality, the lesser culpability of offenders under 16 made the death penalty inappropriate as a form of retribution, while the low likelihood that offenders under 16 engaged in “the kind of cost-benefit analysis that attaches any weight to the possibility of execution” made the death penalty ineffective as a means of deterrence..... 

    The next year, in Stanford v. Kentucky (1989), the Court, over a dissenting opinion joined by four Justices, referred to contemporary standards of decency in this country and concluded the Eighth and Fourteenth Amendments did not proscribe the execution of juvenile offenders over 15 but under 18. The Court noted that 22 of the 37 death penalty States permitted the death penalty for 16-year-old offenders, and, among these 37 States, 25 permitted it for 17-year-old offenders. These numbers, in the Court’s view, indicated there was no national consensus “sufficient to label a particular punishment cruel and unusual....”



The evidence of national consensus against the death penalty for juveniles is similar, and in some respects parallel, to the evidence Atkins held sufficient to demonstrate a national consensus against the death penalty for the mentally retarded. When Atkins was decided, 30 States prohibited the death penalty for the mentally retarded. This number comprised 12 that had abandoned the death penalty altogether, and 18 that maintained it but excluded the mentally retarded from its reach. By a similar calculation in this case, 30 States prohibit the juvenile death penalty, comprising 12 that have rejected the death penalty altogether and 18 that maintain it but, by express provision or judicial interpretation, exclude juveniles from its reach. Atkins emphasized that even in the 20 States without formal prohibition, the practice of executing the mentally retarded was infrequent. In the present case, too, even in the 20 States without a formal prohibition on executing juveniles, the practice is infrequent. Since Stanford, six States have executed prisoners for crimes committed as juveniles. In the past 10 years, only three have done so: Oklahoma, Texas, and Virginia....

We consider the change from Stanford to this case to be significant..... The number of States that have abandoned capital punishment for juvenile offenders since Stanford is smaller than the number of States that abandoned capital punishment for the mentally retarded after Penry; yet we think the same consistency of direction of change has been demonstrated. Since Stanford, no State that previously prohibited capital punishment for juveniles has reinstated it. This fact, coupled with the trend toward abolition of the juvenile death penalty, carries special force in light of the general popularity of anticrime legislation and in light of the particular trend in recent years toward cracking down on juvenile crime in other respects.

    The slower pace of abolition of the juvenile death penalty over the past 15 years, moreover, may have a simple explanation. When we heard Penry, only two death penalty States had already prohibited the execution of the mentally retarded. When we heard Stanford, by contrast, 12 death penalty States had already prohibited the execution of any juvenile under 18, and 15 had prohibited the execution of any juvenile under 17. If anything, this shows that the impropriety of executing juveniles between 16 and 18 years of age gained wide recognition earlier than the impropriety of executing the mentally retarded. In the words of the Missouri Supreme Court: “It would be the ultimate in irony if the very fact that the inappropriateness of the death penalty for juveniles was broadly recognized sooner than it was recognized for the mentally retarded were to become a reason to continue the execution of juveniles now that the execution of the mentally retarded has been barred....”

    Petitioner cannot show national consensus in favor of capital punishment for juveniles but still resists the conclusion that any consensus exists against it. Petitioner supports this position with, in particular, the observation that when the Senate ratified the International Covenant on Civil and Political Rights (ICCPR), Dec. 19, 1966, 999 U. N. T. S. 171 (entered into force Mar. 23, 1976), it did so subject to the President’s proposed reservation regarding Article 6(5) of that treaty, which prohibits capital punishment for juveniles. Brief for Petitioner 27. This reservation at best provides only faint support for petitioner’s argument. First, the reservation was passed in 1992; since then, five States have abandoned capital punishment for juveniles. Second, Congress considered the issue when enacting the Federal Death Penalty Act in 1994, and determined that the death penalty should not extend to juveniles. See 18 U.S.C. § 3591. The reservation to Article 6(5) of the ICCPR provides minimal evidence that there is not now a national consensus against juvenile executions.

    As in Atkins, the objective indicia of consensus in this case–the rejection of the juvenile death penalty in the majority of States; the infrequency of its use even where it remains on the books; and the consistency in the trend toward abolition of the practice–provide sufficient evidence that today our society views juveniles, in the words Atkins used respecting the mentally retarded, as “categorically less culpable than the average criminal.”

    A majority of States have rejected the imposition of the death penalty on juvenile offenders under 18, and we now hold this is required by the Eighth Amendment....

    Three general differences between juveniles under 18 and adults demonstrate that juvenile offenders cannot with reliability be classified among the worst offenders. First, as any parent knows and as the scientific and sociological studies respondent and his amici cite tend to confirm, “[a] lack of maturity and an underdeveloped sense of responsibility are found in youth more often than in adults and are more understandable among the young. These qualities often result in impetuous and ill-considered actions and decisions......”  The second area of difference is that juveniles are more vulnerable or susceptible to negative influences and outside pressures, including peer pressure.....The third broad difference is that the character of a juvenile is not as well formed as that of an adult. The personality traits of juveniles are more transitory, less fixed.

    These differences render suspect any conclusion that a juvenile falls among the worst offenders....

    In Thompson, a plurality of the Court recognized the import of these characteristics with respect to juveniles under 16, and relied on them to hold that the Eighth Amendment prohibited the imposition of the death penalty on juveniles below that age. We conclude the same reasoning applies to all juvenile offenders under 18....

    Drawing the line at 18 years of age is subject, of course, to the objections always raised against categorical rules. The qualities that distinguish juveniles from adults do not disappear when an individual turns 18. By the same token, some under 18 have already attained a level of maturity some adults will never reach. For the reasons we have discussed, however, a line must be drawn....

    These considerations mean Stanford v. Kentucky should be deemed no longer controlling on this issue.... T


    Our determination that the death penalty is disproportionate punishment for offenders under 18 finds confirmation in the stark reality that the United States is the only country in the world that continues to give official sanction to the juvenile death penalty. This reality does not become controlling, for the task of interpreting the Eighth Amendment remains our responsibility. Yet at least from the time of the Court’s decision in Trop, the Court has referred to the laws of other countries and to international authorities as instructive for its interpretation of the Eighth Amendment’s prohibition of “cruel and unusual punishments.” As respondent and a number of amici emphasize, Article 37 of the United Nations Convention on the Rights of the Child, which every country in the world has ratified save for the United States and Somalia, contains an express prohibition on capital punishment for crimes committed by juveniles under 18.  Respondent and his amici have submitted, and petitioner does not contest, that only seven countries other than the United States have executed juvenile offenders since 1990: Iran, Pakistan, Saudi Arabia, Yemen, Nigeria, the Democratic Republic of Congo, and China. Since then each of these countries has either abolished capital punishment for juveniles or made public disavowal of the practice.  In sum, it is fair to say that the United States now stands alone in a world that has turned its face against the juvenile death penalty....

    It is proper that we acknowledge the overwhelming weight of international opinion against the juvenile death penalty, resting in large part on the understanding that the instability and emotional imbalance of young people may often be a factor in the crime. The opinion of the world community, while not controlling our outcome, does provide respected and significant confirmation for our own conclusions.

    Over time, from one generation to the next, the Constitution has come to earn the high respect and even, as Madison dared to hope, the veneration of the American people. The document sets forth, and rests upon, innovative principles original to the American experience, such as federalism; a proven balance in political mechanisms through separation of powers; specific guarantees for the accused in criminal cases; and broad provisions to secure individual freedom and preserve human dignity. These doctrines and guarantees are central to the American experience and remain essential to our present-day self-definition and national identity. Not the least of the reasons we honor the Constitution, then, is because we know it to be our own. It does not lessen our fidelity to the Constitution or our pride in its origins to acknowledge that the express affirmation of certain fundamental rights by other nations and peoples simply underscores the centrality of those same rights within our own heritage of freedom.

    The Eighth and Fourteenth Amendments forbid imposition of the death penalty on offenders who were under the age of 18 when their crimes were committed. The judgment of the Missouri Supreme Court setting aside the sentence of death imposed upon Christopher Simmons is affirmed.

It is so ordered.

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