with whom Justice O’Con-nor, Justice Scalia, and Justice Kennedy join, dissenting.
The Court here decides that the sentence imposed by a Maryland jury is constitutionally infirm because the Court cannot be certain that each juror understood the sentencing instructions and charges to the jury. Last Term, in California v. Brown, 479 U. S. 538 (1987), we reaffirmed our view that the relevant inquiry is not whether an impermissible interpretation of instructions to the jury, however improbable, is literally possible; it is instead “what a reasonable juror could have understood the charge as meaning.” Id., at 541. I think the instructions and charges to the jury in this case pass this test, and I would affirm petitioner’s sentence as well as his conviction.
I
Petitioner, already serving a 30-year sentence for a murder he committed in 1982, stabbed his cellmate 6 times in the chest and 39 times in the back with a homemade knife. Petitioner had threatened to kill his cellmate several weeks earlier if numerous demands were not met by the prison warden, and on August 6, 1984, he made good on his threat. Evidence at trial strongly suggested that this brutal assault was unprovoked and was initiated while the victim was asleep.
After finding petitioner guilty of first-degree murder, the Maryland jury hearing his case proceeded to the sentencing phase of the trial. As part of the sentencing process, the jury was provided with the standard sentencing form. Although the sentencing form is reproduced in the Appendix to the majority’s opinion, I believe it is useful to review the instructions and the charges that confronted the jurors.
*391Section I of the sentencing form requires the jurors unanimously to determine whether or not several aggravating circumstances existed; the jurors unanimously found that “[t]he defendant committed the murder at a time when he was confined in a correctional institution.” App. 99-101. After reaching this decision, the jury moved on to Section II of the form, which began:
“Based upon the evidence we unanimously find that each of the following mitigating circumstances which is marked ‘yes’ has been proven to exist by A PREPONDERANCE OF THE EVIDENCE and each mitigating circumstance marked ‘no’ has not been proven by A PREPONDERANCE OF THE EVIDENCE.” Appendix to opinion of Court, ante, at 387.
These instructions were followed by seven possible mitigating factors. After each one was the choice “_yes [or]_no”; the jurors checked “no” for each factor, and for the eighth and final question whether “[o]ther mitigating circumstances exist, as set forth below,” the jury wrote “none.” App. 101-103.
The jury’s negative responses, when examined in the light of the directions in Section II, admit of but one reasonable interpretation: the jury unanimously found that no mitigating factors existed that should be weighed against the aggravating circumstance that it unanimously determined was present. This is “what a reasonable juror [would] have understood the charge as meaning,” and there is absolutely no reason to think that this meaning was not abundantly plain to the jurors acting under these instructions.1
*392These instructions, which by themselves would serve as an understandable guide to the jury in its deliberations, were accompanied by additional charges from the trial judge. Although the Court ignores several of these charges, I do not think it open to doubt that they reinforce the jury’s understanding that it must unanimously reach a decision on each question before proceeding to the next. After distributing the sentencing forms, the trial judge delivered the following charges:
“Let me remind you that in reaching your determination as to any of the issues raised by the case and presented to you on this sentencing form your verdict must be unanimous; that is, all twelve of you must agree.
“Now should you find the existence unanimously and beyond a reasonable doubt of aggravating circumstance number two and mark that yes, then you should proceed to section two, which begins at the top of page two. That provides that based upon the evidence we unanimously find that each of the following mitigating circumstances which is marked yes has been proven to exist by a preponderance of the evidence, and each mitigating circumstance marked no has not been proven by a preponderance of the evidence. Again I stress that your finding as to mitigating circumstances must be unanimous, that is you must all agree.
“Again let me stress the requirement of unanimity, that is your finding under section two and your findings *393under section three must be one in which all twelve of you agree.
“Again let me remind you of the burdens of proof as I have defined them for you and the requirement that your verdict or your decision with regard to any of these items must be unanimous.
“Let me remind you that... as you consider each of the circumstances you must indicate yes or no, however your unanimous decision falls.” Id., at 69, 70-71, 73, 74, 95 (emphasis added).
Over and over again, the trial court exhorted the jury that every determination made on the sentencing form had to be a unanimous one. This repeated emphasis, when combined with the instructions on the face of Section II itself, simply had to alert the jury to the requirement of unanimity. To conclude otherwise, as the Court does, applies to the deliberations of jurors and the instructions of judges a requirement of freedom from any ambiguity more suitable to mathematics or the physical sciences than to the affairs of human beings.2
I am also more than a little uncertain about the standard the majority purports to employ in finding that the jury may not have understood its instructions as intended. In California v. Brown, 479 U. S. 538 (1987), we held that the correct inquiry in this situation is “‘what a reasonable juror could have understood the charge as meaning.’” Id., at 541, quot*394ing Francis v. Franklin, 471 U. S. 307, 316 (1985); see also Sandstrom v. Montana, 442 U. S. 510, 516-517 (1979). Thus, in Brown we found that a reasonable juror would reject the construction of the jury charge advanced by the defendant, and would instead understand that the trial judge’s instruction not to rely on “mere sympathy” was “a directive to ignore only the sort of sympathy that would be totally divorced from the evidence adduced during the penalty phase.” 479 U. S., at 542. Similarly, in Jurek v. Texas, 428 U. S. 262 (1976), a majority of the Court concluded that the issues arising in the Texas sentencing proceeding “have a common-sense core of meaning and that criminal juries should be capable of understanding them.” Id., at 279 (White, J., concurring in judgment) (agreeing with joint opinion by Stewart, Powell, and Stevens, JJ.). Jurek demonstrates that the interpretation a reasonable juror would give to instructions from the trial court is the determinative element in this Court’s review.
For this reason, the Court’s reliance on Lockett v. Ohio, 438 U. S. 586 (1978), and Eddings v. Oklahoma, 455 U. S. 104 (1982), is misplaced. The issue here is not whether the jurors were permitted to hear all the extenuating evidence petitioner cared to present; they undoubtedly were. Rather, as in Brown and Jurek, the question is whether a reasonable juror operating under the trial court’s instructions would have considered this evidence of mitigating circumstances in a constitutional manner. In the present case, would a reasonable juror understand that, to mark “no” to each mitigating factor on the sentencing form, all 12 jurors must agree? The language of Section II of the form, when coupled with the repeated instructions from the trial judge, leaves no doubt that the answer is in the affirmative.
The Court states that “[bjecause we have no reason to believe that the jury also arrived at” the proper interpretation of the sentencing form, petitioner’s sentence must be vacated •and his case remanded for resentencing. Ante, at 369. The *395Court also proposes that “[u]nless we can rule out the substantial possibility that the jury may have rested its verdict” on an improper construction of the sentencing instructions and jury charges, petitioner’s sentence must be set aside. Ante, at 377. This formulation obscures considerably what I view as the correct standard set forth in Brown. Short of ordering a separate trial to investigate the knowledge of each juror and the discussions among all 12, I can envision no method by which the court can ever attain the level of certainty on which the majority insists. Jury deliberations are by nature secret, and the mental processes of individual jurors equally recondite. To demand this degree of assurance in conducting judicial review of jury proceedings would establish a standard which can never be satisfied.
As the preceding discussion indicates, if the “reasonable juror” standard is employed, the instructions on the sentencing form and the charges given to the jury in this case are constitutionally unexceptionable, and petitioner’s sentence should be upheld.
II
Since the majority finds dispositive petitioner’s argument that the jurors may not have understood the unanimity requirements of the sentencing instructions and jury charges, it does not reach the second issue in the case. See ante, at 384, n. 16. Because I would reject the challenge to the instructions, I must continue on and deal with petitioner’s claim that the trial judge improperly allowed into evidence statements concerning the personal characteristics of the victim, Paul Brown, in violation of our recent decision in Booth v. Maryland, 482 U. S. 496 (1987). Although petitioner failed to object at trial to the introduction of this evidence,3 the Maryland Court of Appeals nonetheless found that the information *396about Brown did not constitute a proscribed victim impact statement. The issue is thus properly before this Court, see Orr v. Orr, 440 U. S. 268, 274-275 (1979); Illinois v. Gates, 462 U. S. 213, 218, n. 1 (1983); McGoldrick v. Compagnie Generale Transatlantique, 309 U. S. 430, 434-435 (1940), and I would uphold the Court of Appeals’ determination.
Attached to the Maryland Division of Parole and Probation’s investigation report of the crime was a memorandum to the State’s Attorney, which summarized an interview conducted by a caseworker with the victim’s brother and sister-in-law. After petitioner’s counsel informed the court that he had read the memorandum and did not object to its admission, the trial judge allowed it into evidence. ' In its entirety, the memorandum stated:
“ ‘Paul and Thomas Brown came from a family of six. At a very young age they were removed from their parents [sic] custody because of neglect and placed in separate foster homes. (Removal by the Department of Social Services was prompted by Paul being hospitalized at age 4 for anemia and malnutrition).
“‘Paul was a hyperactive child and hard to handle which resulted in a lot of beatings from his various guardians. He ran away constantly from the various homes in which he had been placed. After a while Paul, at the age of 15, just started living on the streets. He was eventually sent to the Maryland Training School for Boys. Paul never really had a home or a family as such. “I (Thomas Brown) tried to keep in touch with Paul by writing and visiting him whenever possible. I always had good homes and a good life and always felt so guilty that there was nothing I could do to help Paul. After all, I was only one year older than he.”
“ ‘ “Paul was a good person who had a tough life, a lot of bad breaks, no family, no home, nobody to really give him a chance. I sometimes think he felt more secure in prison, because he had no one on the outside. Sure, he *397committed crimes, but he wasn’t violent. He did what he had to do to survive and he got involved with a lot of bad people.’”” 310 Md. 33, 72, n. 14, 527 A. 2d 3, 22, n. 14 (1987).
Several points should be made about this memorandum. First, it did not purport to be, and the Maryland Court of Appeals found that it did not fall within the statutory requirements of, a victim impact statement under Maryland law. See ibid.; see also Md. Ann. Code, Art. 41, §4-609(c) (1986). The statements summarized in the memorandum did not describe the effect of the murder on the family and friends of the victim. Nor did the memorandum contain opinions and characterizations by Paul Brown’s brother and sister-in-law of the crime. At most, this thumbnail sketch of the victim’s difficult childhood and frequent encounters with correctional authorities gave the jury a quick glimpse of the life petitioner chose to extinguish.
I joined the dissents in Booth v. Maryland, supra, at 515 and 519, and continue to believe that that case was wrongly decided. Virtually no limits are placed on the mitigating evidence a capital defendant may introduce concerning his own history and circumstances, yet the State is precluded from demonstrating the loss to the victim’s family, and to society as a whole, through the defendant’s homicide. If a jury is to assess meaningfully the defendant’s moral culpability and blameworthiness, one essential consideration should be the extent of the harm caused by the défendant. In large measure, the Court’s decision in Booth prevents the jury from having before it all the information necessary to determine the proper punishment for a first-degree murder.
But even if I were to accept the majority’s rationale in Booth, I would still find that the statements about the victim summarized in the present memorandum were correctly admitted into evidence. The victim impact statements ruled inadmissible in Booth, in addition to containing information about the elderly couple killed by the defendant, also in-*398eluded substantial material concerning the effect of the crime on the victims’ family and friends, the loss to the community, and the family’s perceptions of the defendant. By contrast, the summary admitted here gave only the barest of details about Paul Brown himself and no information at all about the impact of his death on others. I do not interpret Booth as foreclosing the introduction of all evidence, in whatever form, about a murder victim, and would thus conclude that the trial court did not commit error in admitting the summary in this case.
The majority attempts, through the backdoor of a footnote, see ante, at 380, n. 14, to explain what an individual juror might have considered persuasive as a mitigating circumstance. In addition to pointing up the fact that the majority has no evidence to support the hypothetical reading of the sentencing form it imputes to the jury, a review of the mitigating factors offered by petitioner in this case reveals that they were extraordinarily weak. At sentencing, petitioner urged that his “youthful age” of 20 *392should weigh in his favor, and argued that, despite the fact that he had murdered twice, it was “unlikely that [he would] engage in further criminal activity that would constitute a continuing threat to society.” 310 Md. 33, 57, 527 A. 2d 3, 14 (1987). Petitioner also asserted as an extenuating circumstance the failure of the State effectively to reform him. In view of the vacuity of these proffered mitigating factors, it is hardly surprising that the jury would unanimously reject them.
The Court seems to derive support from the fact that the Maryland Court of Appeals has recently modified its sentencing form, see ante, at 381-383. While any clarification in the form is of course welcome, the amendment is of no legal relevance to our decision today. As discussion at oral argument suggested, a sentencing instruction that is constitutionally acceptable may be improved in any number of ways. Tr. of Oral Arg. 11-12. Our determination here is only whether the sentencing instructions and the jury charges submitted in this case were permissible.
Petitioner did, however, challenge the Maryland Court of Appeals’ decision on the admissibility of the evidence about the victim in his petition for certiorari and in his brief. See Pet. for Cert. 8-10; Brief for Petitioner 21-24.