(Slip Opinion)              OCTOBER TERM, 2015                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                              KANSAS v. CARR

         CERTIORARI TO THE SUPREME COURT OF KANSAS

   No. 14–449.      Argued October 7, 2015—Decided January 20, 2016*
A Kansas jury sentenced respondent Sidney Gleason to death for killing
  a co-conspirator and her boyfriend to cover up the robbery of an elder-
  ly man.
     A Kansas jury sentenced respondents Reginald and Jonathan Carr,
  brothers, to death after a joint sentencing proceeding. Respondents
  were convicted of various charges stemming from a notorious crime
  spree that culminated in the brutal rape, robbery, kidnaping, and ex-
  ecution-style shooting of five young men and women.
     The Kansas Supreme Court vacated the death sentences in each
  case, holding that the sentencing instructions violated the Eighth
  Amendment by failing “to affirmatively inform the jury that mitigat-
  ing circumstances need only be proved to the satisfaction of the indi-
  vidual juror in that juror’s sentencing decision and not beyond a rea-
  sonable doubt.” It also held that the Carrs’ Eighth Amendment right
  “to an individualized capital sentencing determination” was violated
  by the trial court’s failure to sever their sentencing proceedings.
Held:
     1. The Eighth Amendment does not require capital-sentencing
  courts to instruct a jury that mitigating circumstances need not be
  proved beyond a reasonable doubt. Pp. 8–13.
        (a) Because the Kansas Supreme Court left no doubt that its rul-
  ing was based on the Federal Constitution, Gleason’s initial argu-
  ment—that this Court lacks jurisdiction to hear his case because the
  state court’s decision rested on adequate and independent state-law
  grounds—is rejected. See Kansas v. Marsh, 548 U. S. 163, 169.
  Pp. 8–9.
——————
   *Together with No. 14–450, Kansas v. Carr, and No. 14–452, Kansas
v. Gleason, also on certiorari to the same court.
2                            KANSAS v. CARR

                                  Syllabus

          (b) This Court’s capital-sentencing case law does not support re-
    quiring a court to instruct a jury that mitigating circumstances need
    not be proved beyond a reasonable doubt. See, e.g., Buchanan v. An-
    gelone, 522 U. S. 269, 275. Nor was such an instruction constitution-
    ally necessary in these particular cases to avoid confusion. Ambigui-
    ty in capital-sentencing instructions gives rise to constitutional error
    only if “there is a reasonable likelihood that the jury has applied the
    challenged instruction in a way that prevents the consideration of
    constitutionally relevant evidence,” Boyde v. California, 494 U. S.
    370, 380, a bar not cleared here. Even assuming that it would be un-
    constitutional to require the defense to prove mitigating circumstanc-
    es beyond a reasonable doubt, the record belies the defendants’ con-
    tention that the instructions caused jurors to apply such a standard
    of proof here. The instructions make clear that both the existence of
    aggravating circumstances and the conclusion that they outweigh
    mitigating circumstances must be proved beyond a reasonable doubt
    but that mitigating circumstances must merely be “found to exist,”
    which does not suggest proof beyond a reasonable doubt. No juror
    would have reasonably speculated that “beyond a reasonable doubt”
    was the correct burden for mitigating circumstances. Pp. 9–13.
       2. The Constitution did not require severance of the Carrs’ joint
    sentencing proceedings. The Eighth Amendment is inapposite when
    a defendant’s claim is, at bottom, that evidence was improperly ad-
    mitted at a capital-sentencing proceeding. The question is whether
    the allegedly improper evidence “so infected the sentencing proceed-
    ing with unfairness as to render the jury’s imposition of the death
    penalty a denial of due process.” Romano v. Oklahoma, 512 U. S. 1,
    12. In light of all the evidence presented at the guilt and penalty
    phases relevant to the jury’s sentencing determination, the conten-
    tion that the admission of mitigating evidence by one Carr brother
    could have “so infected” the jury’s consideration of the other’s sen-
    tence as to amount to a denial of due process is beyond the pale. The
    Court presumes that the jury followed its instructions to “give sepa-
    rate consideration to each defendant.” Bruton v. United States, 391
    U. S. 123, distinguished. Joint proceedings are permissible and often
    preferable when the joined defendants’ criminal conduct arises out of
    a single chain of events. Buchanan v. Kentucky, 483 U. S. 402, 418.
    Limiting instructions, like those given in the Carrs’ proceeding, “of-
    ten will suffice to cure any risk of prejudice,” Zafiro v. United States,
    506 U. S. 534, 539, that might arise from codefendants’ “antagonistic”
    mitigation theories, id., at 538. It is improper to vacate a death sen-
    tence based on pure “speculation” of fundamental unfairness, “rather
    than reasoned judgment.” Romano, supra, at 13–14. Only the most
    extravagant speculation would lead to the conclusion that any sup-
                    Cite as: 577 U. S. ____ (2016)                 3

                              Syllabus

  posedly prejudicial evidence rendered the Carr brothers’ joint sen-
  tencing proceeding fundamentally unfair when their acts of almost
  inconceivable cruelty and depravity were described in excruciating
  detail by the sole survivor, who, for two days, relived the Wichita
  Massacre with the jury. Pp. 13–17.
No. 14–449, 300 Kan. 340, 329 P. 3d 1195; No. 14–450, 300 Kan. 1, 331
 P. 3d 544; and No. 14–452, 299 Kan. 1127, 329 P. 3d 1102, reversed
 and remanded.

  SCALIA, J., delivered the opinion of the Court, in which ROBERTS,
C. J., and KENNEDY, THOMAS, GINSBURG, BREYER, ALITO, and KAGAN,
JJ., joined. SOTOMAYOR, J., filed a dissenting opinion.
                       Cite as: 577 U. S. ____ (2016)                              1

                            Opinion of the Court

    NOTICE: This opinion is subject to formal revision before publication in the
    preliminary print of the United States Reports. Readers are requested to
    notify the Reporter of Decisions, Supreme Court of the United States, Wash-
    ington, D. C. 20543, of any typographical or other formal errors, in order
    that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                  _________________

                    Nos. 14–449, 14–450, and 14–452
                                  _________________


                      KANSAS, PETITIONER
14–449                         v.
                       JONATHAN D. CARR

                   KANSAS, PETITIONER
14–450                      v.
                REGINALD DEXTER CARR, JR.

                      KANSAS, PETITIONER
14–452                         v.
                       SIDNEY J. GLEASON

   ON WRITS OF CERTIORARI TO THE SUPREME COURT OF 

                       KANSAS

                              [January 20, 2016]


  JUSTICE SCALIA delivered the opinion of the Court.
  The Supreme Court of Kansas vacated the death sen-
tences of Sidney Gleason and brothers Reginald and Jona-
than Carr. Gleason killed one of his co-conspirators and
her boyfriend to cover up the robbery of an elderly man.
The Carrs’ notorious Wichita crime spree culminated in
the brutal rape, robbery, kidnaping, and execution-style
shooting of five young men and women. We first consider
whether the Constitution required the sentencing courts
to instruct the juries that mitigating circumstances “need
not be proved beyond a reasonable doubt.” And second,
2                         KANSAS v. CARR

                        Opinion of the Court

whether the Constitution required severance of the Carrs’
joint sentencing proceedings.
                             I

                            A

  Less than one month after Sidney Gleason was paroled
from his sentence for attempted voluntary manslaughter,
he joined a conspiracy to rob an elderly man at knife-
point.1 Gleason and a companion “cut up” the elderly man
to get $10 to $35 and a box of cigarettes. 299 Kan. 1127,
1136, 329 P. 3d 1102, 1115 (2014). Fearing that their
female co-conspirators would snitch, Gleason and his
cousin, Damien Thompson, set out to kill co-conspirator
Mikiala Martinez. Gleason shot and killed Martinez’s
boyfriend, and then Gleason and Thompson drove Mar-
tinez to a rural location, where Thompson strangled her
for five minutes and then shot her in the chest, Gleason
standing by and providing the gun for the final shot.
  The State ultimately charged Gleason with capital
murder for killing Martinez and her boyfriend, first-degree
premeditated murder of the boyfriend, aggravating kid-
naping of Martinez, attempted first-degree murder and
aggravated robbery of the elderly man, and criminal pos-
session of a firearm. He was convicted on all counts except
the attempted first-degree murder charge. Id., at 1134–
1135, 1146, 329 P. 3d, at 1114, 1120. The jury also found
that the State proved beyond a reasonable doubt the
existence of four aggravating circumstances and unani-
mously agreed to a sentence of death. Id., at 1146–1147,
329 P. 3d, at 1120–1121.
                          B
    In December 2000, brothers Reginald and Jonathan
——————
  1 The facts for this portion of the opinion come from the Kansas Su-

preme Court, 299 Kan. 1127, 1134–1147, 329 P. 3d 1102, 1113–1121
(2014), and the parties’ briefs.
                    Cite as: 577 U. S. ____ (2016)                  3

                        Opinion of the Court

Carr set out on a crime spree culminating in the Wichita
Massacre.2 On the night of December 7, Reginald Carr
and an unknown man carjacked Andrew Schreiber, held a
gun to his head, and forced him to make cash withdrawals
at various ATMs.
   On the night of December 11, the brothers followed
Linda Ann Walenta, a cellist for the Wichita symphony,
home from orchestra practice. One of them approached
her vehicle and said he needed help. When she rolled
down her window, he pointed a gun at her head. When
she shifted into reverse to escape, he shot her three times,
ran back to his brother’s car, and fled the scene. One of
the gunshots severed Walenta’s spine, and she died one
month later as a result of her injuries.
   On the night of December 14, the brothers burst into a
triplex at 12727 Birchwood, where roommates Jason,
Brad, and Aaron lived. Jason’s girlfriend, Holly, and
Heather, a friend of Aaron’s, were also in the house.
Armed with handguns and a golf club, the brothers forced
all five into Jason’s bedroom. They demanded that they
strip naked and later ordered them into the bedroom
closet. They took Holly and Heather from the bedroom,
demanded that they perform oral sex and digitally pene-
trate each other as the Carrs looked on and barked orders.
They forced each of the men to have sex with Holly and
then with Heather. They yelled that the men would be
shot if they could not have sex with the women, so Holly—
fearing for Jason’s life—performed oral sex on him in the
closet before he was ordered out by the brothers.
   Jonathan then snatched Holly from the closet. He
ordered that she digitally penetrate herself. He set his
——————
  2 The facts for this portion of the opinion come from the Kansas Su-

preme Court, 300 Kan. 1, 18–38, 331 P. 3d 544, 575–586 (2014), and
witness testimony. See 21–A Tr. 59–75 (Oct. 7, 2002), 22–B Tr. 39–124
(Oct. 8, 2002), 23–A Tr. 4–118 (Oct. 9, 2002), 23–B Tr. 5–133 (Oct. 9,
2002), and 24–A Tr. 4–93 (Oct. 10, 2002).
4                     KANSAS v. CARR

                     Opinion of the Court

gun between her knees on the floor. And he raped her.
Then he raped Heather.
  Reginald took Brad, Jason, Holly, and Aaron one-by-one
to various ATMs to withdraw cash. When the victims
returned to the house, their torture continued. Holly uri-
nated in the closet because of fright. Jonathan found an
engagement ring hidden in the bedroom that Jason was
keeping as a surprise for Holly. Pointing his gun at Jason,
he had Jason identify the ring while Holly was sitting
nearby in the closet. Then Reginald took Holly from the
closet, said he was not going to shoot her yet, and raped
her on the dining-room floor strewn with boxes of Christ-
mas decorations. He forced her to turn around, ejaculated
into her mouth, and forced her to swallow. In a nearby
bathroom, Jonathan again raped Heather and then again
raped Holly.
  At 2 a.m.—three hours after the mayhem began—the
brothers decided it was time to leave the house. They
attempted to put all five victims in the trunk of Aaron’s
Honda Civic. Finding that they would not all fit, they
jammed the three young men into the trunk. They di-
rected Heather to the front of the car and Holly to Jason’s
pickup truck, driven by Reginald. Once the vehicles ar-
rived at a snow-covered field, they instructed Jason and
Brad, still naked, and Aaron to kneel in the snow. Holly
cried, “Oh, my God, they’re going to shoot us.” Holly and
Heather were then ordered to kneel in the snow. Holly
went to Jason’s side; Heather, to Aaron.
  Holly heard the first shot, heard Aaron plead with the
brothers not to shoot, heard the second shot, heard the
screams, heard the third shot, and the fourth. She felt the
blow of the fifth shot to her head, but remained kneeling.
They kicked her so she would fall face-first into the snow
and ran her over in the pickup truck. But she survived,
because a hair clip she had fastened to her hair that night
deflected the bullet. She went to Jason, took off her
                 Cite as: 577 U. S. ____ (2016)           5

                     Opinion of the Court

sweater, the only scrap of clothing the brothers had let her
wear, and tied it around his head to stop the bleeding from
his eye. She rushed to Brad, then Aaron, and then
Heather.
   Spotting a house with white Christmas lights in the
distance, Holly started running toward it for help—naked,
skull shattered, and without shoes, through the snow and
over barbed-wire fences. Each time a car passed on the
nearby road, she feared it was the brothers returning and
camouflaged herself by lying down in the snow. She made
it to the house, rang the doorbell, knocked. A man opened
the door, and she relayed as quickly as she could the
events of the night to him, and minutes later to a 911
dispatcher, fearing that she would not live.
   Holly lived, and retold this play-by-play of the night’s
events to the jury. Investigators also testified that the
brothers returned to the Birchwood house after leaving
the five friends for dead, where they ransacked the place
for valuables and (for good measure) beat Holly’s dog,
Nikki, to death with a golf club.
   The State charged each of the brothers with more than
50 counts, including murder, rape, sodomy, kidnaping,
burglary, and robbery, and the jury returned separate
guilty verdicts. It convicted Reginald of one count of kid-
naping, aggravated robbery, aggravated battery, and
criminal damage to property for the Schreiber carjacking,
and one count of first-degree felony murder for the Walenta
shooting. Jonathan was acquitted of all counts related
to the Schreiber carjacking but convicted of first-degree
felony murder for the Walenta shooting. For the Birch-
wood murders, the jury convicted each brother of 4 counts
of capital murder, 1 count of attempted first-degree mur-
der, 5 counts of aggravated kidnaping, 9 counts of aggra-
vated robbery, 20 counts of rape or attempted rape, 3
counts of aggravated criminal sodomy, 1 count each of
aggravated burglary and burglary, 1 count of theft, and 1
6                     KANSAS v. CARR

                     Opinion of the Court

count of cruelty to animals. The jury also convicted Reg-
inald of three counts of unlawful possession of a firearm.
300 Kan. 1, 15–16, 331 P. 3d 544, 573–574 (2014).
  The State sought the death penalty for each of the four
Birchwood murders, and the brothers were sentenced
together. The State relied on the guilt-phase evidence,
including Holly’s two days of testimony, as evidence of four
aggravating circumstances: that the defendants knowingly
or purposely killed or created a great risk of death to more
than one person; that they committed the crimes for the
purpose of receiving money or items of monetary value;
that they committed the crimes to prevent arrest or pro-
secution; and that they committed the crimes in an espe-
cially heinous, atrocious, or cruel manner. Id., at 258–259,
331 P. 3d, at 708. After hearing each brother’s case for
mitigation, the jury issued separate verdicts of death for
Reginald and Jonathan. It found unanimously that the
State proved the existence of the four aggravating circum-
stances beyond a reasonable doubt and that those aggra-
vating circumstances outweighed the mitigating circum-
stances, justifying four separate verdicts of death for each
brother for the murders of Jason, Brad, Aaron, and
Heather. App. in No. 14–449 etc., pp. 461–492.
                            C
  The Kansas Supreme Court vacated the death penalties
in both cases. It held that the instructions used in both
Gleason’s and the Carrs’ sentencing violated the Eighth
Amendment because they “failed to affirmatively inform
the jury that mitigating circumstances need only be
proved to the satisfaction of the individual juror in that
juror’s sentencing decision and not beyond a reasonable
doubt.” 299 Kan., at 1196, 329 P. 3d, at 1147 (Gleason);
300 Kan., at 303, 331 P. 3d, at 733 (Reginald Carr); 300
Kan. 340, 369–370, 329 P. 3d 1195, 1213 (2014) (Jonathan
Carr). Without that instruction, according to the court,
                 Cite as: 577 U. S. ____ (2016)           7

                     Opinion of the Court

the jury “was left to speculate as to the correct burden of
proof for mitigating circumstances, and reasonable jurors
might have believed they could not consider mitigating
circumstances not proven beyond a reasonable doubt.”
299 Kan., at 1197, 329 P. 3d, at 1148. This, the court
concluded, might have caused jurors to exclude relevant
mitigating evidence from their consideration. Ibid.
   The Kansas Supreme Court also held that the Carrs’
death sentences had to be vacated because of the trial
court’s failure to sever their sentencing proceedings,
thereby violating the brothers’ Eighth Amendment right
“to an individualized capital sentencing determination.”
300 Kan., at 275, 331 P. 3d, at 717; 300 Kan., at 368, 329
P. 3d, at 1212. According to the court, the joint trial “in-
hibited the jury’s individualized consideration of [Jona-
than] because of family characteristics tending to demon-
strate future dangerousness that he shared with his
brother”; and his brother’s visible handcuffs prejudiced the
jury’s consideration of his sentence. 300 Kan., at 275, 331
P. 3d, at 717. As for Reginald, he was prejudiced, accord-
ing to the Kansas Supreme Court, by Jonathan’s portrayal
of him as the corrupting older brother. Id., at 276, 331
P. 3d, at 717. Moreover, Reginald was prejudiced by his
brother’s cross-examination of their sister, who testified
that she thought Reginald had admitted to her that he
was the shooter. Id., at 279, 331 P. 3d, at 719. (She later
backtracked and testified, “ ‘I don’t remember who was,
you know, shot by who[m].’ ” Ibid.) The Kansas Supreme
Court opined that the presumption that the jury followed
its instructions to consider each defendant separately was
“defeated by logic.” Id., at 280, 331 P. 3d, at 719. “[T]he
defendants’ joint upbringing in the maelstrom that was
their family and their influence on and interactions with
one another . . . simply was not amenable to orderly sepa-
ration and analysis.” Ibid., 331 P. 3d, at 719–720. The
Kansas Supreme Court found itself unable to “say that the
8                     KANSAS v. CARR

                     Opinion of the Court

death verdict was unattributable, at least in part, to this
error.” Id., at 282, 331 P. 3d, at 720. We granted certio-
rari. 575 U. S. ___ (2015).
                             II
   We first turn to the Kansas Supreme Court’s contention
that the Eighth Amendment required these capital-
sentencing courts to instruct the jury that mitigating
circumstances need not be proved beyond a reasonable
doubt.
                              A
   Before considering the merits of that contention, we
consider Gleason’s challenge to our jurisdiction. According
to Gleason, the Kansas Supreme Court’s decision rests on
adequate and independent state-law grounds. This argu-
ment is a familiar one. We rejected it in Kansas v. Marsh,
548 U. S. 163, 169 (2006). Like the defendant in that case,
Gleason urges that the decision below rests only on a rule
of Kansas law announced in State v. Kleypas, 272 Kan.
894, 40 P. 3d 139 (2001) (per curiam)—a rule later reiter-
ated in State v. Scott, 286 Kan. 54, 183 P. 3d 801 (2008)
( per curiam). As we stated in Marsh, “Kleypas, itself,
rested on federal law.” 548 U. S., at 169. So too does the
relevant passage of Scott, which rested on Kleypas’s dis-
cussion of the constitutional rule that jurors need not
agree on mitigating circumstances. See Scott, supra, at
106–107, 183 P. 3d, at 837–838. The Kansas Supreme
Court’s opinion in this case acknowledged as much, saying
that “statements from Kleypas implicate the broader
Eighth Amendment principle prohibiting barriers that
preclude a sentencer’s consideration of all relevant miti-
gating evidence.” 299 Kan., at 1195, 329 P. 3d, at 1147.
   The Kansas Supreme Court’s opinion leaves no room for
doubt that it was relying on the Federal Constitution. It
stated that the instruction it required “protects a capital
                 Cite as: 577 U. S. ____ (2016)            9

                     Opinion of the Court

defendant’s Eighth Amendment right to individualized
sentencing,” that the absence of the instruction “im-
plicat[ed] Gleason’s right to individualized sentencing
under the Eighth Amendment,” and that vacatur of
Gleason’s death sentence was the “[c]onsequen[ce]” of
Eighth Amendment error. Id., at 1196–1197, 329 P. 3d, at
1147–1148 (emphasis added).
   For this reason, the criticism leveled by the dissent is
misdirected. It generally would have been “none of our
business” had the Kansas Supreme Court vacated
Gleason’s and the Carrs’ death sentences on state-law
grounds. Marsh, 548 U. S., at 184 (SCALIA, J., concurring).
But it decidedly did not. And when the Kansas Supreme
Court time and again invalidates death sentences because
it says the Federal Constitution requires it, “review by this
Court, far from undermining state autonomy, is the only
possible way to vindicate it.” Ibid. “When we correct a
state court’s federal errors, we return power to the State,
and to its people.” Ibid. The state courts may experiment
all they want with their own constitutions, and often do in
the wake of this Court’s decisions. See Sutton, San Anto-
nio Independent School District v. Rodriguez And Its
Aftermath, 94 Va. L. Rev. 1963, 1971–1977 (2008). But
what a state court cannot do is experiment with our Fed-
eral Constitution and expect to elude this Court’s review
so long as victory goes to the criminal defendant. “Turn-
ing a blind eye” in such cases “would change the uniform
‘law of the land’ into a crazy quilt.” Marsh, supra, at 185.
And it would enable state courts to blame the unpopular
death-sentence reprieve of the most horrible criminals
upon the Federal Constitution when it is in fact their own
doing.
                           B
  We turn, then, to the merits of the Kansas Supreme
Court’s conclusion that the Eighth Amendment requires
10                    KANSAS v. CARR

                     Opinion of the Court

capital-sentencing courts in Kansas “to affirmatively
inform the jury that mitigating circumstances need not be
proven beyond a reasonable doubt.” 299 Kan., at 1197,
329 P. 3d, at 1148.
   Approaching the question in the abstract, and without
reference to our capital-sentencing case law, we doubt
whether it is even possible to apply a standard of proof to
the mitigating-factor determination (the so-called “selec-
tion phase” of a capital-sentencing proceeding). It is pos-
sible to do so for the aggravating-factor determination (the
so-called “eligibility phase”), because that is a purely
factual determination. The facts justifying death set forth
in the Kansas statute either did or did not exist—and one
can require the finding that they did exist to be made
beyond a reasonable doubt. Whether mitigation exists,
however, is largely a judgment call (or perhaps a value
call); what one juror might consider mitigating another
might not. And of course the ultimate question whether
mitigating circumstances outweigh aggravating circum-
stances is mostly a question of mercy—the quality of
which, as we know, is not strained. It would mean noth-
ing, we think, to tell the jury that the defendants must
deserve mercy beyond a reasonable doubt; or must more-
likely-than-not deserve it. It would be possible, of course,
to instruct the jury that the facts establishing mitigating
circumstances need only be proved by a preponderance,
leaving the judgment whether those facts are indeed
mitigating, and whether they outweigh the aggravators, to
the jury’s discretion without a standard of proof. If we
were to hold that the Constitution requires the mitigating-
factor determination to be divided into its factual compo-
nent and its judgmental component, and the former to be
accorded a burden-of-proof instruction, we doubt whether
that would produce anything but jury confusion. In the
last analysis, jurors will accord mercy if they deem it
appropriate, and withhold mercy if they do not, which is
                 Cite as: 577 U. S. ____ (2016)          11

                     Opinion of the Court

what our case law is designed to achieve.
    In any event, our case law does not require capital
sentencing courts “to affirmatively inform the jury that
mitigating circumstances need not be proved beyond a
reasonable doubt.” Ibid. In Buchanan v. Angelone, 522
U. S. 269 (1998), we upheld a death sentence even though
the trial court “failed to provide the jury with express
guidance on the concept of mitigation.” Id., at 275. Like-
wise in Weeks v. Angelone, 528 U. S. 225 (2000), we reaf-
firmed that the Court has “never held that the State must
structure in a particular way the manner in which juries
consider mitigating evidence” and rejected the contention
that it was constitutionally deficient to instruct jurors to
“ ‘consider a mitigating circumstance if you find there is
evidence to support it,’ ” without additional guidance. Id.,
at 232–233.
    Equally unavailing is the contention that even if an
instruction that mitigating evidence need not be “proven
beyond a reasonable doubt” is not always required, it was
constitutionally necessary in these cases to avoid confu-
sion. Ambiguity in capital-sentencing instructions gives
rise to constitutional error only if “there is a reasonable
likelihood that the jury has applied the challenged in-
struction in a way that prevents the consideration of
constitutionally relevant evidence.” Boyde v. California,
494 U. S. 370, 380 (1990) (emphasis added). The alleged
confusion stemming from the jury instructions used at the
defendants’ sentencings does not clear that bar. A meager
“possibility” of confusion is not enough. Ibid.
    As an initial matter, the defendants’ argument rests on
the assumption that it would be unconstitutional to re-
quire the defense to prove mitigating circumstances be-
yond a reasonable doubt. Assuming without deciding that
that is the case, the record belies the defendants’ conten-
tion that the instructions caused jurors to apply that
standard of proof. The defendants focus upon the follow-
12                        KANSAS v. CARR

                         Opinion of the Court

ing instruction: “The State has the burden to prove beyond
a reasonable doubt that there are one or more aggravating
circumstances and that they are not outweighed by any
mitigating circumstances found to exist.” App. to Pet. for
Cert. in No. 14–452, p. 133 (Instr. 8).3 The juxtaposition of
aggravating and mitigating circumstances, so goes the
argument, caused the jury to speculate that mitigating
circumstances must also be proved beyond a reasonable
doubt. 299 Kan., at 1197, 329 P. 3d, at 1148. It seems to
us quite the opposite. The instruction makes clear that
both the existence of aggravating circumstances and the
conclusion that they outweigh mitigating circumstances
must be proved beyond a reasonable doubt; mitigating
circumstances themselves, on the other hand, must merely
be “found to exist.” That same description, mitigating
circumstances “found to exist,” is contained in three other
instructions, App. to Pet. for Cert. in No. 14–452, at 133
(Instrs. 7, 9, and 10) (emphasis added)—unsurprisingly,
since it recites the Kansas statute, see Kan. Stat. Ann.
§21–4624(e) (1995). “Found to exist” certainly does not
suggest proof beyond a reasonable doubt. The instructions
as a whole distinguish clearly between aggravating and
mitigating circumstances: “The State has the burden to
prove beyond a reasonable doubt that there are one or
more aggravating circumstances . . . ,” and the jury must
decide unanimously that the State met that burden. App.
to Pet. for Cert. in No. 14–452, at 133 (Instrs. 8 and 10)
(emphasis added). “Mitigating circumstances,” on the
other hand, “do not need to be found by all members of the
jury” to “be considered by an individual juror in arriving at
his or her sentencing decision.” Id., at 131 (Instr. 7). Not
once do the instructions say that defense counsel bears the
——————
  3 The relevant penalty-phase instructions from the Carrs’ sentencing

proceedings are materially indistinguishable. See App. to Pet. for Cert.
in No. 14–450, pp. 501–510.
                 Cite as: 577 U. S. ____ (2016)          13

                     Opinion of the Court

burden of proving the facts constituting a mitigating
circumstance beyond a reasonable doubt—nor would that
make much sense, since one of the mitigating circum-
stances is (curiously) “mercy,” which simply is not a fac-
tual determination.
   We reject the Kansas Supreme Court’s decision that
jurors were “left to speculate as to the correct burden of
proof for mitigating circumstances.” 299 Kan., at 1197,
329 P. 3d, at 1148. For the reasons we have described, no
juror would reasonably have speculated that mitigating
circumstances must be proved by any particular standard,
let alone beyond a reasonable doubt. The reality is that
jurors do not “pars[e] instructions for subtle shades of
meaning in the same way that lawyers might.” Boyde,
supra, at 381. The instructions repeatedly told the jurors
to consider any mitigating factor, meaning any aspect of
the defendants’ background or the circumstances of their
offense. Jurors would not have misunderstood these
instructions to prevent their consideration of constitution-
ally relevant evidence.
                            III
  We turn next to the contention that a joint capital-
sentencing proceeding in the Carrs’ cases violated the
defendants’ Eighth Amendment right to an “individualized
sentencing determination.” 300 Kan., at 276, 331 P. 3d, at
717.
  The Kansas Supreme Court agreed with the defendants
that, because of the joint sentencing proceeding, one de-
fendant’s mitigating evidence put a thumb on death’s scale
for the other, in violation of the other’s Eighth Amend-
ment rights. Ibid. It accepted Reginald’s contention that
he was prejudiced by his brother’s portrayal of him as the
corrupting older brother. And it agreed that Reginald was
prejudiced by his brother’s cross-examination of their
sister, who equivocated about whether Reginald admitted
14                        KANSAS v. CARR

                         Opinion of the Court

to her that he was the shooter. (Reginald has all but
abandoned that implausible theory of prejudice before this
Court and contends only that the State “likely would not
have introduced any such testimony” had he been sen-
tenced alone. Brief for Respondent in No. 14–450, p. 34,
n. 3.) Jonathan asserted that he was prejudiced by evi-
dence associating him with his dangerous older brother,
which caused the jury to perceive him as an incurable
sociopath.4 Both speculate that the evidence assertedly
prejudicial to them would have been inadmissible in sev-
ered proceedings under Kansas law. The Kansas Supreme
Court also launched a broader attack on the joint proceed-
ings, contending that the joinder rendered it impossible for
the jury to consider the Carrs’ relative moral culpability
and to determine individually whether they were entitled
to “mercy.” 300 Kan., at 278, 331 P. 3d, at 718–719.
   Whatever the merits of defendants’ procedural objec-
tions, we will not shoehorn them into the Eighth Amend-
ment’s prohibition of “cruel and unusual punishments.”
As the United States as amicus curiae intimates, the
Eighth Amendment is inapposite when each defendant’s
claim is, at bottom, that the jury considered evidence that
would not have been admitted in a severed proceeding,
and that the joint trial clouded the jury’s consideration of
mitigating evidence like “mercy.” Brief for United States
24, n. 8. As we held in Romano v. Oklahoma, 512 U. S. 1
(1994), it is not the role of the Eighth Amendment to
establish a special “federal code of evidence” governing
“the admissibility of evidence at capital sentencing pro-
ceedings.” Id., at 11–12. Rather, it is the Due Process
——————
   4 Jonathan also alleges that he was prejudiced by the jury’s witness-

ing his brother’s handcuffs, which his brother requested remain visible
before the penalty phase commenced. That allegation is mystifying.
That his brother’s handcuffs were visible (while his own restraints were
not) more likely caused the jury to see Jonathan as the less dangerous
of the two.
                 Cite as: 577 U. S. ____ (2016)          15

                     Opinion of the Court

Clause that wards off the introduction of “unduly prejudi-
cial” evidence that would “rende[r] the trial fundamentally
unfair.” Payne v. Tennessee, 501 U. S. 808, 825 (1991); see
also Brown v. Sanders, 546 U. S. 212, 220–221 (2006).
   The test prescribed by Romano for a constitutional
violation attributable to evidence improperly admitted at a
capital-sentencing proceeding is whether the evidence “so
infected the sentencing proceeding with unfairness as to
render the jury’s imposition of the death penalty a denial
of due process.” 512 U. S., at 12. The mere admission of
evidence that might not otherwise have been admitted in a
severed proceeding does not demand the automatic vaca-
tur of a death sentence.
   In light of all the evidence presented at the guilt and
penalty phases relevant to the jury’s sentencing determi-
nation, the contention that the admission of mitigating
evidence by one brother could have “so infected” the jury’s
consideration of the other’s sentence as to amount to a
denial of due process is beyond the pale. To begin with,
the court instructed the jury that it “must give separate
consideration to each defendant,” that each was “entitled
to have his sentence decided on the evidence and law
which is applicable to him,” and that any evidence in the
penalty phase “limited to only one defendant should not be
considered by you as to the other defendant.” App. to Pet.
for Cert. in No. 14–450, at 501 (Instr. 3). The court gave
defendant-specific instructions for aggravating and miti-
gating circumstances. Id., at 502–508 (Instrs. 5, 6, 7, and
8). And the court instructed the jury to consider the “indi-
vidual” or “particular defendant” by using four separate
verdict forms for each defendant, one for each murdered
occupant of the Birchwood house. Id., at 509 (Instr. 10);
App. in No. 14–449 etc., at 461–492. We presume the jury
followed these instructions and considered each defendant
separately when deciding to impose a sentence of death for
each of the brutal murders. Romano, supra, at 13.
16                    KANSAS v. CARR

                     Opinion of the Court

   The contrary conclusion of the Kansas Supreme Court—
that the presumption that jurors followed these instruc-
tions was “defeated by logic,” 300 Kan., at 280, 331 P. 3d,
at 719—is untenable. The Carrs implausibly liken the
prejudice resulting from the joint sentencing proceeding to
the prejudice infecting the joint trial in Bruton v. United
States, 391 U. S. 123 (1968), where the prosecution admit-
ted hearsay evidence of a codefendant’s confession impli-
cating the defendant. That particular violation of the
defendant’s confrontation rights, incriminating evidence of
the most persuasive sort, ineradicable, as a practical
matter, from the jury’s mind, justified what we have de-
scribed as a narrow departure from the presumption that
jurors follow their instructions, Richardson v. Marsh, 481
U. S. 200, 207 (1987). We have declined to extend that
exception, id., at 211, and have continued to apply the
presumption to instructions regarding mitigating evidence
in capital-sentencing proceedings, see, e.g., Weeks, 528
U. S., at 234. There is no reason to think the jury could
not follow its instruction to consider the defendants sepa-
rately in this case.
   Joint proceedings are not only permissible but are often
preferable when the joined defendants’ criminal conduct
arises out of a single chain of events. Joint trial may
enable a jury “to arrive more reliably at its conclusions
regarding the guilt or innocence of a particular defendant
and to assign fairly the respective responsibilities of each
defendant in the sentencing.” Buchanan v. Kentucky, 483
U. S. 402, 418 (1987). That the codefendants might have
“antagonistic” theories of mitigation, Zafiro v. United
States, 506 U. S. 534, 538 (1993), does not suffice to over-
come Kansas’s “interest in promoting the reliability and
consistency of its judicial process,” Buchanan, supra, at
418. Limiting instructions, like those used in the Carrs’
sentencing proceeding, “often will suffice to cure any risk
of prejudice.” Zafiro, supra, at 539 (citing Richardson,
                 Cite as: 577 U. S. ____ (2016)          17

                     Opinion of the Court

supra, at 211). To forbid joinder in capital-sentencing
proceedings would, perversely, increase the odds of “wan-
to[n] and freakis[h]” imposition of death sentences. Gregg
v. Georgia, 428 U. S. 153, 206–207 (1976) (joint opinion of
Stewart, Powell, and Stevens, JJ.). Better that two de-
fendants who have together committed the same crimes be
placed side-by-side to have their fates determined by a
single jury.
   It is improper to vacate a death sentence based on pure
“speculation” of fundamental unfairness, “rather than
reasoned judgment,” Romano, supra, at 13–14. Only the
most extravagant speculation would lead to the conclusion
that the supposedly prejudicial evidence rendered the
Carr brothers’ joint sentencing proceeding fundamentally
unfair. It is beyond reason to think that the jury’s death
verdicts were caused by the identification of Reginald as
the “corrupter” or of Jonathan as the “corrupted,” the
jury’s viewing of Reginald’s handcuffs, or the sister’s re-
tracted statement that Reginald fired the final shots.
None of that mattered. What these defendants did—acts
of almost inconceivable cruelty and depravity—was de-
scribed in excruciating detail by Holly, who relived with
the jury, for two days, the Wichita Massacre. The joint
sentencing proceedings did not render the sentencing
proceedings fundamentally unfair.
                             IV
  When we granted the State’s petition for a writ of certio-
rari for the Carrs’ cases, we declined to review whether
the Confrontation Clause, U. S. Const., Amdt. 6, requires
that defendants be allowed to cross-examine witnesses
whose statements are recorded in police reports referred to
by the State in penalty-phase proceedings. The Kansas
Supreme Court did not make the admission of those
statements a basis for its vacating of the death sentences,
but merely “caution[ed]” that in the resentencing proceed-
18                    KANSAS v. CARR

                     Opinion of the Court

ings these out-of-court testimonial statements should be
omitted, 300 Kan., at 288, 331 P. 3d, at 724. We are confi-
dent that cross-examination regarding these police reports
would not have had the slightest effect upon the sen-
tences. See Delaware v. Van Arsdall, 475 U. S. 673, 684
(1986).
                       *     *     *
  The judgments of the Supreme Court of Kansas are
reversed, and these cases are remanded for further pro-
ceedings not inconsistent with this opinion.

                                            It is so ordered.
                       Cite as: 577 U. S. ____ (2016)                              1

                         SOTOMAYOR, J., dissenting

    NOTICE: This opinion is subject to formal revision before publication in the
    preliminary print of the United States Reports. Readers are requested to
    notify the Reporter of Decisions, Supreme Court of the United States, Wash-
    ington, D. C. 20543, of any typographical or other formal errors, in order
    that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                  _________________

                     Nos. 14–449, 14-450, and 14–452
                                  _________________


                      KANSAS, PETITIONER
14–449                         v.
                       JONATHAN D. CARR

                   KANSAS, PETITIONER
14–450                      v.
                REGINALD DEXTER CARR, JR.

                      KANSAS, PETITIONER
14–452                         v.
                       SIDNEY J. GLEASON

   ON WRITS OF CERTIORARI TO THE SUPREME COURT OF 

                       KANSAS

                              [January 20, 2016]


  JUSTICE SOTOMAYOR, dissenting.
  I respectfully dissent because I do not believe these
cases should ever have been reviewed by the Supreme
Court. I see no reason to intervene in cases like these—
and plenty of reasons not to. Kansas has not violated any
federal constitutional right. If anything, the State has
overprotected its citizens based on its interpretation of
state and federal law. For reasons ably articulated by my
predecessors and colleagues and because I worry that
cases like these prevent States from serving as necessary
laboratories for experimenting with how best to guarantee
2                      KANSAS v. CARR

                   SOTOMAYOR, J., dissenting

defendants a fair trial, I would dismiss the writs as improvi-
dently granted.
                              I
   In 2014, the Kansas Supreme Court vacated three death
sentences—the sentences of Sidney Gleason and the Carr
brothers, Reginald and Jonathan—because of constitu-
tional errors in the penalty phases of their trials.
   All three men were tried under jury instructions that
did not include language previously mandated by the
Kansas Supreme Court. The instructions did not state
that, under Kansas’ statutory scheme, mitigating circum-
stances need only be proven to an individual juror’s satis-
faction and not beyond a reasonable doubt. 299 Kan.
1127, 1192–1197, 329 P. 3d 1102, 1145–1148 (2014) (Sid-
ney Gleason); 300 Kan. 1, 302–303, 331 P. 3d 544, 732–
733 (2014) (Reginald Carr); 300 Kan. 340, 368–369, 329
P. 3d 1195, 1213 (2014) (Jonathan Carr). The court found
that the instructions therefore both undermined Kansas’
state law and created a “reasonable likelihood that the
jury . . . applied the challenged instruction in a way that
prevents consideration” of mitigating evidence as required
by the Federal Constitution. 299 Kan., at 1191–1197, 329
P. 3d, at 1144–1148 (quoting Boyde v. California, 494
U. S. 370, 380 (1990)).
   The Kansas Supreme Court also vacated the Carr
brothers’ death sentences because they were jointly tried
at the penalty phase. The court concluded that each
brother’s particular case for mitigation compromised the
other brother’s case and therefore that trying them jointly
violated the Eighth Amendment right to individualized
sentencing. The error was not harmless, the Kansas
Supreme Court found, because an “especially damning
subset” of the evidence presented might not have been
admitted in separate penalty proceedings. 300 Kan., at
275–282, 331 P. 3d, at 717–720; 300 Kan., at 369–370, 329
                 Cite as: 577 U. S. ____ (2016)            3

                   SOTOMAYOR, J., dissenting

P. 3d, at 1212.
  The Kansas attorney general requested certiorari, alleg-
ing that it would best serve the State’s interest for a fed-
eral court to intervene and correct the Kansas Supreme
Court. This Court complied, even though there was no
suggestion that the Kansas Supreme Court had violated
any federal constitutional right. The majority now reverses
the Kansas Supreme Court on both points.
                              II

                               A

   Even where a state court has wrongly decided an “im-
portant question of federal law,” Sup. Ct. Rule 10, we often
decline to grant certiorari, instead reserving such grants
for instances where the benefits of hearing a case out-
weigh the costs of so doing. My colleagues and predeces-
sors have effectively set forth many of the costs of granting
certiorari in cases where state courts grant relief to crimi-
nal defendants: We risk issuing opinions that, while not
strictly advisory, may have little effect if a lower court is
able to reinstate its holding as a matter of state law.
Florida v. Powell, 559 U. S. 50, 66 (2010) (Stevens, J.,
dissenting). We expend resources on cases where the only
concern is that a State has “ ‘overprotected’ ” its citizens.
Michigan v. Long, 463 U. S. 1032, 1068 (1983) (Stevens, J.,
dissenting). We intervene in an intrastate dispute be-
tween the State’s executive and its judiciary rather than
entrusting the State’s structure of government to sort it
out. See Coleman v. Thompson, 501 U. S. 722, 766–767
(1991) (Blackmun, J., dissenting). And we lose valuable
data about the best methods of protecting constitutional
rights—a particular concern in cases like these, where the
federal constitutional question turns on the “reasonable
likelihood” of jury confusion, an empirical question best
answered with evidence from many state courts. Cf.
Arizona v. Evans, 514 U. S. 1, 30–31 (1995) (GINSBURG, J.,
4                      KANSAS v. CARR

                    SOTOMAYOR, J., dissenting

dissenting).
                               B
   The cases here demonstrate yet another cost of granting
certiorari to correct a state court’s overprotection of federal
rights: In explaining that the Federal Constitution does
not protect some particular right, it is natural to buttress
the conclusion by explaining why that right is not very
important. In so doing, the Court risks discouraging
States from adopting valuable procedural protections even
as a matter of their own state law.
   State experimentation with how best to guarantee a fair
trial to criminal defendants is an essential aspect of our
federalism scheme. See, e.g., Linde, First Things First:
Rediscovering the States’ Bill of Rights, 9 U. Balt. L. Rev.
379, 393 (1980). The Federal Constitution guarantees
only a minimum slate of protections; States can and do
provide individual rights above that constitutional floor.
See, e.g., Brennan, The Bill of Rights and the States: the
Revival of State Constitutions as Guardians of Constitu-
tional Rights, 61 N. Y. U. L. Rev. 535, 548–550 (1986).
That role is particularly important in the criminal arena
because state courts preside over many millions more
criminal cases than their federal counterparts and so are
more likely to identify protections important to a fair trial.
Compare Court Statistics Project, Examining the Work of
State Courts: An Analysis of 2010 State Court Caseloads
19–21 (2012), with Dept. of Justice, Bureau of Justice
Statistics, Federal Justice Statistics 2011–2012, pp. 19–20
(Jan. 2015) (Tables 11 and 12).
   The majority’s opinion in these cases illustrates how an
unnecessary grant of certiorari can lead to unexpected
costs by disrupting this sort of state experimentation.
Take the first question presented in these cases. The
majority’s actual holding is that the Eighth Amendment
does not require an instruction specifying that mitigating
                     Cite as: 577 U. S. ____ (2016)                   5

                      SOTOMAYOR, J., dissenting

factors need not be proven beyond a reasonable doubt.
Ante, at 11–12. The Eighth Amendment has nothing to
say about whether such an instruction is wise as a ques-
tion of state law or policy. But the majority nonetheless
uses this Court’s considerable influence to call into ques-
tion the logic of specifying any burden of proof as to miti-
gating circumstances. The majority claims that while
assessing an aggravating factor is “a purely factual deter-
mination,” assessing mitigation involves “a judgment call
(or perhaps a value call)” and is thus not amenable to
burdens of proof. Ante, at 10. Short of dividing the miti-
gating factor “into its factual component and its judgmen-
tal component,” and issuing burden-of-proof instructions
only as to the former, the majority wonders “whether it is
even possible to apply a standard of proof to the mitigating-
factor determination.” Ibid.
   By this observation, and with no experience with the
needs of juries, the majority denigrates the many States
that do specify a burden of proof for the existence of miti-
gating factors as a matter of state law, presumably under
the belief that it is, in fact, “possible” to do so.* Brief for
Respondent in No. 14–452, pp. 28–29, and n. 6. Some
States even recommend an instruction specifying that
mitigating factors need not be proven beyond a reasonable
doubt. See, e.g., Idaho Jury Instr., Crim., ICJI 1718, Jury
Deliberations (2010); Okla. Jury Instr., Crim, OUJI–CR 4–
78 (2015).
   The majority’s discussion of severance likewise short
circuits state experimentation. The majority is not con-
——————
  * I leave aside the merits of the majority’s questionable distinction,
though I cannot see how the jury’s conclusion that the Carr brothers
committed their crime “in an especially heinous, atrocious or cruel
manner”—one of the aggravating circumstances found by the Carr
brothers’ jury—involved any less of a judgment or value call than the
mitigating circumstances alleged. See 300 Kan. 1, 282–283, 331 P. 3d
544, 721 (2014).
6                      KANSAS v. CARR

                   SOTOMAYOR, J., dissenting

tent to hold that the Eighth Amendment does not, strictly
speaking, require severance of capital penalty proceedings.
Instead, it goes on to explain why joint capital sentencing
proceedings are not only permissible under the Federal
Constitution but are, in fact, preferable as a policy matter:
“Better that two defendants who have together committed
the same crimes be placed side-by-side to have their
fates determined by a single jury.” Ante, at 17. The ma-
jority even intimates that severed proceedings may be
worse for defendants: “To forbid joinder in capital-
sentencing proceedings would, perversely, increase the
odds of ‘wanto[n] and freakis[h]’ imposition of death sen-
tences.” Ibid. (quoting Gregg v. Georgia, 428 U. S. 153,
206–207 (1976) (joint opinion of Stewart, Powell, and
Stevens, JJ.).
   So much for Ohio’s, Georgia’s, and Mississippi’s sentenc-
ing regimes, all of which routinely allow severance at both
phases of capital proceedings. See Ga. Code Ann. §17–8–4
(2013) (upon request, defendants must be tried separately
in capital cases); Miss. Code Ann. §99–15–47 (2015)
(same); Ohio Rev. Code Ann. §2945.20 (Lexis 2014) (capi-
tal defendants shall be tried separately unless good cause
is shown for a joint trial). There is no evidence that any of
those three States adopted a severance regime based on a
misunderstanding of the Eighth Amendment. But without
any empirical foundation or any basis in experience, the
majority asserts that such regimes may increase the odds
of arbitrariness.
   The majority claims that we “ ‘return power to the State,
and to its people,’ ” when we explain that the Federal
Constitution does not require a particular result. Ante, at
9 (emphasis deleted). But that is only so when the Court
is able to pass solely on the federal constitutional ground
and not the wisdom of a state holding on an equivalent
question. Though the Court pretends that it sends back
cases like this one with a clean slate, it rarely fully erases
                  Cite as: 577 U. S. ____ (2016)            7

                   SOTOMAYOR, J., dissenting

its thoughts on the virtues of the procedural protection
at issue. By placing a thumb on the scale against a
State adopting—even as a matter of state law—proce-
dural protections the Constitution does not require, the
Court risks turning the Federal Constitution into a
ceiling, rather than a floor, for the protection of individual
liberties.
                             III
  I see no reason why these three cases out of the Kansas
Supreme Court warranted our intervention given the costs
that I have just described and those described by my
predecessors and colleagues, see supra, at 3. No federal
right has been compromised. And nobody disputes that
the State of Kansas could, as a matter of state law, reach
the same outcome.
  Perhaps most importantly, both of the questions on
which the Court granted certiorari turn on specific fea-
tures of Kansas’ sentencing scheme. As a result, the
Kansas Supreme Court’s opinion is unlikely to have much
salience for other States. If the Kansas Supreme Court
was wrong, its wrong opinion will not subvert federal law
on a broader scale.
  First, the Kansas court’s decision on the jury instruction
question aimed to “both preserv[e] the [state] statute’s
favorable distinction and protec[t] a capital defendant’s
Eighth Amendment right to individualized sentencing by
ensuring jurors are not precluded from considering all
relevant mitigating evidence.” 299 Kan., at 1196, 329
P. 3d, at 1147 (emphasis added). The Kansas Supreme
Court’s decision was thus informed by a combination of
federal and state considerations. A decision that expressly
relies on a State’s unique statutory scheme—as did the
Kansas Supreme Court’s here—has limited potential for
influencing other States.
  It is not absurd to conclude that a juror unfamiliar with
8                     KANSAS v. CARR

                   SOTOMAYOR, J., dissenting

the mechanics of the law might be confused by Kansas’
jury instructions, which almost always mention aggravat-
ing and mitigating instructions in the same breath. Id., at
1196–1197, 329 P. 3d, at 1147–1148. The Kansas Su-
preme Court’s opinion rested largely on the specific lan-
guage and ordering of that State’s instructions. Other
States’ jury instructions may be less likely to have the
same effect.
  Moreover, the decision below was made against the
unique backdrop of trial courts’ failure to implement the
Kansas Supreme Court’s earlier demands for a change to
jury instructions in capital cases. In a 2001 case, the
Kansas Supreme Court considered the jury instructions
insufficiently confusing to reverse the judgment, but suffi-
ciently confusing to demand higher clarity going forward:
“[A]ny instruction dealing with the consideration of miti-
gating circumstances should state (1) they need to be
proved only to the satisfaction of the individual juror in
the juror’s sentencing decision and not beyond a reason-
able doubt and (2) mitigating circumstances do not need to
be found by all members of the jury in order to be consid-
ered in an individual juror’s sentencing decision.” State v.
Kleypas, 272 Kan. 894, 1078, 40 P. 3d 139, 268. The Kan-
sas pattern instructions were then revised to include
consideration (2), but—“inexplicably,” as the court noted
in Gleason—not consideration (1). 299 Kan., at 1193, 329
P. 3d, at 1145. The Kansas Supreme Court reiterated the
two requirements for any jury instruction in 2008, see
State v. Scott, 286 Kan. 54, 106–108, 183 P. 3d 801, 837,
and the pattern instructions were finally changed in 2011,
see 299 Kan., at 1193, 329 P. 3d, at 1145. But Gleason
and the Carr brothers were tried in the 10-year delay
between the Kansas Supreme Court’s initial admonition
and when the jury instructions were finally edited. The
Kansas Supreme Court’s opinion in Gleason may have
rested in part on a “broader Eighth Amendment princi-
                  Cite as: 577 U. S. ____ (2016)            9

                   SOTOMAYOR, J., dissenting

ple,” but it also rested on some lower courts’ failure to give
instructions reflecting the Kansas Supreme Court’s “re-
peated recognition of the required content.” 299 Kan., at
1195, 329 P. 3d, 1146, 1147. Given this context, the Kan-
sas Supreme Court’s decision is particularly unlikely to
undermine other States or the Federal Constitution.
  The same goes for the severance question. The Kansas
Supreme Court’s decision depended on the “especially
damning subset” of the aggravating evidence presented
that may not have been admitted in a severed proceeding
under Kansas’ capital punishment scheme and evidentiary
rules, such as evidence that one brother was a bad influ-
ence on the other. Ibid. But the difference between a joint
penalty phase and a severed penalty phase may be of
limited significance in States where the same evidence
may be admitted in joint and severed proceedings. Cf.
Brown v. Sanders, 546 U. S. 212, 217 (2006); L. Palmer,
The Death Penalty in the United States: A Complete
Guide to Federal and State Laws 137 (2d ed. 2014). It
thus seems to me unlikely that the Kansas Supreme
Court’s opinion would have proven instructive in other
States, even though it was couched in the language of the
Federal Constitution.
                              IV
  There may, of course, be rare cases where certiorari is
warranted in which a state prosecutor alleges that a
State’s highest court has overprotected a criminal defend-
ant. These circumstances may include: Where a state
court’s decision in favor of a criminal defendant implicates
another constitutional right, see, e.g., Nebraska Press
Assn. v. Stuart, 427 U. S. 539, 547 (1976); where a state
court indicates a hostility to applying federal precedents,
Florida v. Meyers, 466 U. S. 380, 383 (1984) ( per curiam)
(Stevens, J., dissenting); or where a state court’s grant of
relief is particularly likely to destabilize or significantly
interfere with federal policy. None of those circumstances,
10                    KANSAS v. CARR

                   SOTOMAYOR, J., dissenting

and no comparable interest, is present in these cases.
  The Carr brothers committed acts of “almost inconceiv-
able cruelty and depravity,” and the majority is under-
standably anxious to ensure they receive their just de-
serts. (So anxious, in fact, that it reaches out to address a
question on which we did not grant certiorari at all. Ante,
at 17). But I do not believe that interest justifies not only
“correcting” the Kansas Supreme Court’s error but also
calling into question the procedures of other States.
  The standard adage teaches that hard cases make bad
law. See Northern Securities Co. v. United States, 193
U. S. 197, 364 (1904) (Holmes, J., dissenting). I fear that
these cases suggest a corollary: Shocking cases make too
much law. Because I believe the Court should not have
granted certiorari here, I respectfully dissent.
