United States v. Tsarnaev

P R E L I M I N A R Y P R I N T
Volume 595 U. S. Part 2
Pages 302–343
OFFICIAL REPORTS
OF
T H E S U P R E M E C O U R T
March 4, 2022
REBECCA A. WOMELDORF
reporter of decisions
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302 OCTOBER
TERM, 2021
Syllabus
UNITED STATES v. TSARNAEV
certiorari
to the united states court of appeals for
the rst circuit
No. 20–443. Argued October 13, 2021—Decided March 4, 2022
On April 15, 2013, brothers Dzhokhar and Tamerlan Tsarnaev planted and
detonated two homemade pressure-cooker bombs near the fnish line of
the Boston Marathon, killing three and wounding hundreds. Three
days later, as investigators began to close in, the brothers fed. In the
process, they murdered a Massachusetts Institute of Technology campus
police offcer, carjacked a graduate student, and fought a street battle
with police during which Dzhokhar inadvertently ran over and killed
Tamerlan. Dzhokhar eventually abandoned the vehicle and hid in a
covered boat being stored in a nearby backyard. He was arrested the
following day.
Dzhokhar was indicted for 30 crimes, including 17 capital offenses.
To prepare for jury selection, the parties proposed a 100-question
screening form, which included several questions regarding whether
media coverage may have biased prospective jurors. The District
Court declined to include a proposed question that asked each prospec-
tive juror to list the facts he had learned about the case from the media
and other sources. According to the District Court, the question was
too “unfocused” and “unguided.” Following three weeks of in-person
questioning, a jury was seated. The jury found Dzhokhar guilty on all
counts, and the Government sought the death penalty.
At sentencing, Dzhokhar sought mitigation based on the theory that
Tamerlan had masterminded the bombing and pressured Dzhokhar to
participate. In an attempt to show Tamerlan's domineering nature,
Dzhokhar sought to introduce the statements of Ibragim Todashev, who
had alleged during an FBI interview that, years earlier, Tamerlan had
participated in a triple homicide in Waltham, Massachusetts. The Gov-
ernment asked the trial court to exclude any reference to the Waltham
murders on the grounds that the evidence either lacked relevance or,
alternatively, lacked probative value and was likely to confuse the is-
sues. The Government also pointed out that, because FBI agents had
killed Todashev in self-defense after he attacked them during the inter-
view, there were no living witnesses to the Waltham murders. The
District Court excluded the evidence, and the jury concluded that 6 of
Dzhokhar's crimes warranted the death penalty.
The Court of Appeals vacated Dzhokhar's capital sentences on two
grounds. First, the court held that the District Court abused its discre-

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303
Syllabus
tion during jury selection by declining to ask about the kind and degree
of
each prospective juror's media exposure, as required by that court's
decision in Patriarca v. United States, 402 F. 2d 314. Second, the court
held that the District Court abused its discretion during sentencing
when it excluded evidence concerning Tamerlan's possible involvement
in the Waltham murders.
Held: The Court of Appeals improperly vacated Dzhokhar's capital sen-
tences. Pp. 312–324.
(a) The District Court did not abuse its discretion by declining to ask
about the content and extent of each juror's media consumption regard-
ing the bombings. Jury selection falls “particularly within the province
of the trial judge,” Skilling v. United States, 561 U. S. 358, 386, whose
broad discretion in this area includes deciding what questions to ask
prospective jurors, see Mu'Min v. Virginia, 500 U. S. 415, 427. Here,
the District Court did not abuse that discretion when, recognizing the
signifcant pretrial publicity concerning the bombings, the court refused
to allow the question at issue because it wrongly emphasized what a
juror knew before coming to court, rather than potential bias. That
decision was reasonable and well within the court's discretion.
The rest of the jury-selection process in this case dispels any remain-
ing doubt. The District Court used the 100-question juror form—which
asked prospective jurors what media sources they followed and whether
any of that information had caused them to form an opinion about
Dzhokhar's guilt or punishment—to cull down the number of prospec-
tive jurors. The District Court then subjected those remaining pro-
spective jurors to three weeks of individualized voir dire, including
questions that probed for bias. Finally, the court instructed the pro-
spective jurors during voir dire, and the seated jurors during trial, that
their decisions must be based on the evidence presented at trial and not
any other source.
The Court of Appeals erred when it concluded that the District Court
abused its discretion by failing to put Dzhokhar's proposed media-
content question to the jury. Following its decision in Patriarca, the
court concluded that it had “supervisory authority” to require the Dis-
trict Court, as a matter of law, to ask the jurors that specifc question.
The supervisory power of federal courts, however, does not extend to
the creation of prophylactic supervisory rules that circumvent or supple-
ment legal standards set out in decisions of this Court. See United
States v. Payner, 447 U. S. 727, 733–737. Pp. 312–317.
(b) Nor did the District Court abuse its discretion in excluding from
the sentencing proceedings evidence of the Waltham murders. The
Federal Death Penalty Act provides that, at the sentencing phase of a
capital trial, “information may be presented as to any matter relevant
to the sentence, including any mitigating or aggravating factor.” 18

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304 UNITED
STATES v. TSARNAEV
Syllabus
U. S. C. § 3593(c). But the district court may exclude information “if its
probative
value is outweighed by the danger of creating unfair preju-
dice, confusing the issues, or misleading the jury.” Ibid. Such eviden-
tiary decisions are reviewed for abuse of discretion. See United States
v. Abel, 469 U. S. 45, 54. Here, Dzhokhar sought to introduce evidence
linking Tamerlan to the unsolved Waltham murders to support his miti-
gation defense that Tamerlan was the ringleader of the bombing. That
evidence, however, did not allow the jury to confrm or assess Tamer-
lan's alleged role in the Waltham murders. The District Court did not
abuse its discretion when it reasonably excluded the evidence for its
lack of probative value and potential to confuse the jury. Dzhokhar's
counterarguments are unconvincing. First, § 3593(c) does not violate
the Eighth Amendment. That provision falls well within the Fed-
eral Government's “ `traditional authority' ” “to decide that certain types
of evidence may have insuffcient probative value to justify their admis-
sion,” Skipper v. South Carolina, 476 U. S. 1, 11, 15 (Powell, J., concur-
ring in judgment), and “to set reasonable limits upon the evidence a
[capital] defendant can submit, and control the manner in which it is
submitted,” Oregon v. Guzek, 546 U. S. 517, 526. Section 3593(c) sets
up a highly permissive regime that allows criminal defendants to intro-
duce a wide range of normally inadmissible evidence and channels that
evidence through an individualized balancing test that affords a capital
defendant every reasonable opportunity to place relevant mitigation evi-
dence before the penalty-phase jury. Here, the bare inclusion of the
Waltham-murders evidence risked producing a confusing mini-trial
where the only witnesses who knew the truth were dead. That the
evidence excluded by the District Court was considered reliable enough
to include in a search warrant has no bearing here, where the District
Court was free to evaluate the information independently when deciding
whether to admit it under § 3593(c).
The dissent recognizes that the District Court enjoyed signifcant dis-
cretion over its evidentiary decisions. But because this is a death pen-
alty case, the dissent scrutinizes those decisions with particular care to
fnd that the District Court abused its discretion. In doing so, the dis-
sent ignores the traditional abuse-of-discretion standard, which calls for
a reviewing court to defer to the sound judgment of a district court
unless the decision was “manifestly erroneous.” General Elec. Co. v.
Joiner, 522 U. S. 136, 142. More specifcally, the dissent suggests that a
district court presiding over death-penalty proceedings should be more
hesitant to fnd that evidence risked confusing the jury. But nothing
in § 3593(c) suggests that Congress intended for any such hesitancy.
Ultimately, the District Court reasonably decided to exclude the evi-
dence under § 3593(c)'s balancing test. Pp. 317–324.
968 F. 3d 24, reversed.

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Opinion of the Court
Thomas, J., delivered the opinion of the Court, in which Roberts, C. J.,
and
Alito, Gorsuch, Kavanaugh, and Barrett, JJ., joined. Barrett,
J., fled a concurring opinion, in which Gorsuch, J., joined, post, p. 324.
Breyer, J., fled a dissenting opinion, in which Sotomayor and Kagan,
JJ., joined except as to Part II–C, post, p. 327.
Deputy Solicitor General Feigin argued the cause for the
United States. With him on the brief were Acting Solicitor
General Prelogar, Assistant Attorney General Demers, Act-
ing Assistant Attorney General McQuaid, Christopher G.
Michel, Michael R. Huston, William A. Glaser, and Joseph
F. Palmer.
Ginger D. Anders argued the cause for respondent. With
her on the brief were Brendan B. Gants, David Patton,
Deirdre D. von Dornum, Daniel Habib, and Cliff Gardner.*
Justice Thomas delivered the opinion of the Court.
On April 15, 2013, Dzhokhar and Tamerlan Tsarnaev plant-
ed and detonated two homemade pressure-cooker bombs
near the fnish line of the Boston Marathon. The blasts
hurled nails and metal debris into the assembled crowd, kill-
ing three while maiming and wounding hundreds. Three
days later, the brothers murdered a campus police offcer,
carjacked a graduate student, and fred on police who had
located them in the stolen vehicle. Dzhokhar attempted to
*Briefs of amici curiae urging reversal were fled for the Criminal Jus-
tice Legal Foundation by Kent S. Scheidegger; and for the National Fra-
ternal Order of Police by William M. Jay, Benjamin Hayes, and Larry
H. James.
Briefs of amici curiae urging affrmance were fled for the American
Bar Association by Barbara J. Howard and Zachary D. Tripp; for the
American Civil Liberties Union et al. by Catherine E. Stetson, David M.
Porter, Brian W. Stull, Cassandra Stubbs, David D. Cole, John W. White-
head, Jennesa Calvo-Friedman, Matthew R. Segal, and Ruth A. Bour-
quin; for Evidence and Sentencing Law Professors by Dean A. Strang;
and for Retired Federal Judges et al. by Kannon K. Shanmugam.
Briefs of amici curiae were fled for Shirin Bakhshay et al. by Stephen
M. Nickelsburg; for James Fetzer, Ph. D., et al. by John Remington Gra-
ham; and for Professor Michael J. Z. Mannheimer by Mr. Mannheimer,
pro se, Jennifer Keighley, and Melanie L. Bostwick.
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306 UNITED
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fee in the vehicle but inadvertently killed Tamerlan by run-
ni
ng him over. Dzhokhar was soon arrested and indicted.
A jury found Dzhokhar guilty of 30 federal crimes and rec-
ommended the death penalty for 6 of them. The District
Court accordingly sentenced Dzhokhar to death. The Court
of Appeals vacated the death sentence. We now reverse.
I
A
The Tsarnaev brothers immigrated to the United States in
the early 2000s and lived in Massachusetts. Little more
than a decade later, they were actively contemplating how
to wage radical jihad. They downloaded and read al Qaeda
propaganda, and, by December of 2012, began studying an al
Qaeda guide to bomb making.
On April 15, 2013, the brothers went to the Boston Mara-
thon fnish line on Boylston Street. They each brought a
backpack containing a homemade pressure-cooker bomb
packed with explosives inside a layer of nails, BBs, and other
metal scraps. Tamerlan left his backpack in a crowd of
spectators and walked away. Dzhokhar stood with his back-
pack outside the Forum, a nearby restaurant where specta-
tors watched the runners from the sidewalk and dining patio.
For four minutes, Dzhokhar surveyed the crowd. After
speaking with Tamerlan by phone, Dzhokhar left his back-
pack among the spectators. Tamerlan then detonated his
bomb. While the crowd at the Forum looked toward the
explosion, Dzhokhar walked the other way. After a few sec-
onds, he detonated his bomb.
Each detonation sent fre and shrapnel in all directions.
The blast from Tamerlan's bomb shattered Krystle Camp-
bell's left femur and mutilated her legs. Though bystanders
tried to save her, she bled to death on the sidewalk. Dzhok-
har's bomb ripped open the legs of Boston University student
Lingzi Lu. Rescuers tried to stem the bleeding by using a
belt as a makeshift tourniquet. She too bled to death.
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Opinion of the Court
Eight-year-old Martin Richard absorbed the full blast of
Dzhokhar
's bomb. BBs, nails, and other metal fragments
shot through his abdomen, cutting through his aorta, spinal
cord, spleen, liver, pancreas, left kidney, and large intestines.
The blast propelled shrapnel with such force that it exited
his back. Other shrapnel nearly severed his left hand. The
explosion also caused third-degree bur ns. Mar tin u lti-
mately died from blood loss.
Dzhokhar's and Tamerlan's bombs maimed and wounded
hundreds of other victims. Many people lost limbs, in-
cluding Martin's 6-year-old sister, Jane. Many more would
have died if not for the swift action of citizens and frst
responders.
After feeing the scene, the brothers returned to their nor-
mal lives. Dzhokhar attended his college classes the next
day. He went to the gym with friends. He posted online
that he was “a stress free kind of guy.” App. 145. Several
days later, on April 18, after the Federal Bureau of Investi-
gation (FBI) released images of the suspected bombers, a
friend saw the images and texted Dzhokhar. Dzhokhar re-
sponded: “Better not text me my friend. Lol.” Id., at 146.
Recognizing that investigators were closing in on them,
Dzhokhar met up with Tamerlan that evening. The broth-
ers collected more homemade bombs and a handgun and
loaded them into Tamerlan's car. While driving past the
Massachusetts Institute of Technology, they saw 27-year-old
campus police offcer Sean Collier sitting in his patrol car.
They approached his car and shot him fve times at close
range, including once between the eyes. With Collier dead,
the brothers tried to steal his service pistol but were unable
to remove it from the holster. They then carjacked and
robbed another man, Dun Meng, who was driving his SUV
home from work. When the brothers forced Meng to stop
at a gas station for fuel and snacks, he fed on foot. The
brothers briefy chased him but gave up and made off with
Meng 's SUV.
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Meng contacted the police, who used the SUV's GPS
de
vice to track the Tsarnaevs. When offcers found the
brothers in Watertown a few hours later, a street battle en-
sued. Tamerlan fred on the offcers with a handgun, while
Dzhokhar threw homemade bombs. When Tamerlan's hand-
gun ran out of ammunition, offcers subdued him. As they
tried to handcuff Tamerlan, Dzhokhar returned to the SUV
and sped towards the offcers. They evaded the SUV.
Tamer lan did not. Dzhokhar ran over Tamer lan and
dragged him roughly 30 feet down the road. Tamerlan dis-
entangled from the undercarriage when Dzhokhar rammed a
police cruiser before escaping. Tamerlan died soon after
from his injuries.
Dzhokhar abandoned the SUV a few blocks away. He
found a covered boat in a nearby backyard. Taking shelter
inside, he carved the words “stop killing our innocent people,
and we will stop” into the planking. Id., at 151. He also
wrote a manifesto in pencil on the bulkhead of the boat's
cockpit justifying his actions and welcoming his expected
martyrdom. The next day, the boat's owner found him.
Police eventually forced Dzhokhar out of the boat and ar-
rested him.
B
A federal grand jury indicted Dzhokhar for 30 crimes, 17
of which were capital offenses. In preparation for jury se-
lection, the parties jointly proposed a 100-question form to
screen the prospective jurors. The District Court adopted
almost all of them, including many that probed for bias. For
example, some of the District Court's questions asked
whether a prospective juror had a close association with law
enforcement. Others asked whether a prospective juror had
strong feelings about Islam, Chechens, or the several Central
Asian regions with which the Tsarnaevs were connected.
Still others asked whether the prospective juror had a per-
sonal connection to the bombing.
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Opinion of the Court
Several questions also probed whether media coverage
might
have biased a prospective juror. One question asked
if the prospective juror had “formed an opinion” about the
case because of what he had “seen or read in the news
media.” App. to Pet. for Cert. 373a. Others asked about
the source, amount, and timing of the person's media con-
sumption. Still another asked whether the prospective
juror had commented or posted online about the bombings.
The District Court did reject one media-related question.
The proposed questionnaire had asked each prospective juror
to list the facts he had learned about the case from the media
and other sources. Concerned that such a broad, “unfo-
cused” question would “cause trouble” by producing “unman-
ageable data” of minimal value that would come to dominate
the entire voir dire, the District Court declined to include it
in the questionnaire. App. 480–481. After Dzhokhar ob-
jected to the removal, the District Court further explained
that the question was “too unguided.” Id., at 486.
Recognizing the intense public interest in the case, the
District Court summoned an expanded jury pool. In early
January 2015, the court called 1,373 prospective jurors for
the frst round of jury selection. After reviewing their an-
swers to the questionnaire, the court reduced the pool to 256.
As jury selection began in earnest, Dzhokhar renewed his
request that the court ask each juror about the content of the
media he had consumed. The District Court again refused
Dzhokhar's blanket request and instead permitted counsel
to ask appropriate followup questions about a prospective
juror's media consumption based on the answers to questions
in the questionnaire or at voir dire. Several times, the court
permitted Dzhokhar's attorneys to follow up on a prospective
juror's earlier answers with specifc questions about what
the juror had seen or heard in the news. Over the course
of three weeks of in-person questioning, the District Court
and the parties reduced the 256 prospective jurors down to
12 seated jurors.
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After the District Court seated the jury, the case went to
tr
ial. Dzhokhar did not contest his guilt and the jury thus
returned a guilty verdict on all counts. During the sentenc-
ing phase, the Government argued that Dzhokhar's crimes
warranted the death penalty. Dzhokhar's mitigation theory
centered on the idea that Tamerlan masterminded the bomb-
ing. According to Dzhokhar, he was not suffciently culpable
to warrant the death penalty because his older brother had
pressured him to participate.
To prove Tamerlan's domineering nature, Dzhokhar sought
to introduce hearsay evidence of a crime Tamerlan allegedly
had committed years earlier. Specifcally, FBI agents inves-
tigating the bombings had come to suspect that Tamerlan's
friend, Ibragim Todashev, possessed information about an
unsolved triple homicide in Waltham, Massachusetts, where
a non-Muslim acquaintance of Tamerlan's and two others
were found bound, robbed, and murdered with a knife.
When agents went to interview Todashev about a month
after the bombings, Todashev initially denied any involve-
ment. Yet, when pressed, he told the agents that Tamerlan
had hatched a plan to rob the three Waltham victims of drug
proceeds on the night of September 11, 2011. According to
Todashev, he and Tamerlan traveled to Waltham, held the
men at gunpoint, and duct-taped their hands, feet, and
mouths. After taking the money, Tamerlan insisted on kill-
ing the three men. According to Todashev, after he dis-
agreed, Tamerlan told him to wait outside while Tamerlan
cut their throats with a knife. The agents offered Todashev
a pen and paper to write out his confession. Todashev in-
stead attacked the agents, who killed him in self-defense.
The FBI later used Todashev's statement to obtain a search
warrant for a follow-on search of Tamerlan's car.
In the lead-up to trial, the prosecution told Dzhokhar's
counsel what Todashev had said but did not turn over the
recording of the interview or the FBI reports. The prosecu-
tion also disclosed that Dias Kadyrbayev, a friend of Dzhok-
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Opinion of the Court
har's facing federal obstruction charges in connection with the
bombi
ng, told the investigators that Dzhokhar knew about
Tamerlan's involvement in the murders. Meanwhile, Gov-
ernment analysts found evidence that someone had searched
for information about the Waltham murders from Tamerlan's
wife's computer a week after they took place. Government
investigators also found jihadi propaganda advocating theft
from non-Muslim “infdels.” Id., at 639.
Before trial, Dzhokhar fled a motion to compel production
of the evidence, which the court denied. The Government
fled a motion in limine to exclude any reference to the Wal-
tham murders, contending that the evidence was irrelevant,
or at least so lacking in probative value and so likely to con-
fuse the issues that the court should exclude it. The Dis-
trict Court granted the Government's motion in limine. As
the District Court saw things, the evidence did not show
what Tamerlan's role was and, with Todashev dead, no fur-
ther line of inquiry remained. The available information
was “without any probative value” and “would be confusing
to the jury and a waste of time.” Id., at 650.
When the sentencing proceedings fnished, the jury con-
cluded that Dzhokhar warranted the death penalty for 6 of
the 17 death-penalty-eligible crimes, despite Dzhokhar's ar-
gument that Tamerlan was more culpable. The District
Court accordingly sentenced Dzhokhar to death.
C
The Court of Appeals vacated Dzhokhar's capital sentence
on two grounds. See 968 F. 3d 24, 35 (CA1 2020). First,
the Court of Appeals held that the District Court abused its
discretion during jury selection by declining to ask every
prospective juror what he learned from the media about the
case. Id., at 54–62. According to the panel, such questions
were required by that court's 1968 decision in Patriarca v.
United States, 402 F. 2d 314 (CA1), which had mandated this
voir dire rule “in the exercise of [the court of appeals'] dis-
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cretionary supervisory powers, not as a matter of constitu-
ti
onal law.” 968 F. 3d, at 60. The Court of Appeals ruled
that the District Court's failure to comply with Patriarca
was “an error of law and so an abuse of discretion.” 968
F. 3d, at 59. Second, the panel held that the District Court
abused its discretion when it excluded from sentencing the
evidence concerning Tamerlan's possible involvement in the
Waltham murders. Id., at 63–73. The panel believed that
the evidence was suffciently probative of Tamerlan's ability
to infuence Dzhokhar. Id., at 69–70. We granted certio-
rari, 592 U. S. ––– (2021).
II
The Government argues that the Court of Appeals im-
properly vacated Dzhokhar's capital sentences based on the
juror questionnaire and the Waltham evidence. We agree.
A
The Sixth Amendment guarantees “the accused” the right
to a trial “by an impartial jury.” The right to an “impartial”
jury “does not require ignorance.” Skilling v. United
States, 561 U. S. 358, 381 (2010). Notorious crimes are “al-
most, as a matter of necessity, brought to the attention” of
those informed citizens who are “best ftted” for jury duty.
Reynolds v. United States, 98 U. S. 145, 155–156 (1879). A
trial court protects the defendant's Sixth Amendment right
by ensuring that jurors have “no bias or prejudice that would
prevent them from returning a verdict according to the law
and evidence.” Connors v. United States, 158 U. S. 408,
413 (1895).
We have repeatedly said that jury selection falls “ `particu-
larly within the province of the trial judge.' ” Skilling, 561
U. S., at 386 (quoting Ristaino v. Ross, 424 U. S. 589, 595
(1976)); see also, e. g., Mu'Min v. Virginia, 500 U. S. 415, 424
(1991); Connors, 158 U. S., at 413. That is so because a trial
“judge's appraisal is ordinarily infuenced by a host of factors
impossible to capture fully in the record,” such as a “prospec-
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Opinion of the Court
tive juror's infection, sincerity, demeanor, candor, body lan-
g
uage, and apprehension of duty.” Skilling, 561 U. S., at
386. A trial court's broad discretion in this area includes
deciding what questions to ask prospective jurors. See
Mu'Min, 500 U. S., at 427 (“our own cases have stressed the
wide discretion granted to the trial court in conducting
voir dire in the area of pretrial publicity”).
A court of appeals reviews the district court's questioning
of prospective jurors only for abuse of discretion. See, e. g.,
Skilling, 561 U. S., at 387, n. 20; Mu'Min, 500 U. S., at 427;
Rosales-Lopez v. United States, 451 U. S. 182, 189 (1981) (plu-
rality opinion); Ristaino, 424 U. S., at 594; Ham v. South
Carolina, 409 U. S. 524, 527 (1973); Connors, 158 U. S., at
413. That discretion does not vanish when a case garners
public attention. Indeed, “[w]hen pretrial publicity is at
issue, `primary reliance on the judgment of the trial court
makes [especially] good sense.' ” Skilling, 561 U. S., at 386
(quoting Mu'Min, 500 U. S., at 427; alteration in Skilling).
After all, “the judge `sits in the locale where the publicity is
said to have had its effect' and may base her evaluation on
her `own perception of the depth and extent of news stories
that might infuence a juror.' ” 561 U. S., at 386 (quoting
Mu'Min, 500 U. S., at 427). Because conducting voir dire is
committed to the district court's sound discretion, there is
no blanket constitutional requirement that it must ask each
prospective juror what he heard, read, or saw about a case
in the media. Mu'Min, 500 U. S., at 417. Instead, as in any
case, the district court's duty is to conduct a thorough jury-
selection process that allows the judge to evaluate whether
each prospective juror is “to be believed when he says he
has not formed an opinion about the case.” Id., at 425.
The District Court did not abuse its broad discretion by
declining to ask about the content and extent of each juror's
media consumption regarding the bombings. The court rec-
ognized the signifcant pretrial publicity concerning the
bombings, and reasonably concluded that the proposed

314 UNITED
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media-content question was “unfocused,” risked producing
“unmanageable
data,” and would at best shed light on “pre-
conceptions” that other questions already probed. App.
480–481. At voir dire, the court further explained that it
did not want to be “too tied to a script” because “[e]very
juror is different” and had to be “questioned in a way that
[was] appropriate” to the juror's earlier answers. Id., at
498. The court was concerned that a media-content ques-
tion had “the wrong emphasis,” focusing on what a juror
knew before coming to court, rather than on potential bias.
Id., at 502. Based on “years” of trial experience, the court
concluded that jurors who came in with some prior knowl-
edge would still be able to act impartially and “hold the
government to its proof.” Id., at 502–503. The District
Court's decision was reasonable and well within its discre-
tion, as our precedents make clear. See Mu'Min, 500 U. S.,
at 427.
If any doubt remained, the rest of the jury-selection proc-
ess dispels it. The District Court summoned an expanded
jury pool of 1,373 prospective jurors and used the 100-
question juror form to cull that down to 256. The question-
naire asked prospective jurors what media sources they fol-
lowed, how much they consumed, whether they had ever
commented on the bombings in letters, calls, or online posts,
and, most pointedly, whether any of that information had
caused the prospective juror to form an opinion about
Dzhokhar's guilt or punishment. The court then subjected
those 256 prospective jurors to three weeks of individualized
voir dire in which the court and both parties had the oppor-
tunity to ask additional questions and probe for bias.
Dzhokhar's attorneys asked several prospective jurors what
they had heard, read, or seen about the case in the media.
The District Court also provided “ `emphatic and clear in-
structions on the sworn duty of each juror to decide the is-
sues only on evidence presented in open court.' ” Skilling,
561 U. S., at 388, n. 21 (quoting Nebraska Press Assn. v.
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Stuart, 427 U. S. 539, 564 (1976)). The court reminded the
prospec
tive jurors that they “must be able to decide the is-
sues in the case based on the information or evidence that is
presented in the course of the trial, not on information from
any other sources,” App. 283, an instruction the court gave
during voir dire and repeated during the trial. In sum, the
court's jury selection process was both eminently reasonable
and wholly consistent with this Court's precedents.
The Court of Appeals erred in holding otherwise. As it
saw things, its decision nearly 50 years prior in Patriarca
had, pursuant to its “supervisory authority,” required dis-
trict courts presiding over high-profle cases to ask about the
“ `kind and degree of [the prospective juror's] exposure to the
case or the parties.' ” 968 F. 3d, at 57 (quoting Patriarca,
402 F. 2d, at 318; emphasis deleted). And because Patriarca
purportedly set forth a “rule,” the District Court's failure to
follow it was “an error of law and so an abuse of discretion.”
968 F. 3d, at 59.
It is true that some of our precedents describe a “supervi-
sory authority” that inheres in federal courts. See, e. g.,
McNabb v. United States, 318 U. S. 332, 343–345 (1943); Cupp
v. Naughten, 414 U. S. 141, 146 (1973).
1
But the Court's
precedents have also identifed clear limits when lower
courts have purported to invoke that authority. For exam-
ple, supervisory rules cannot confict with or circumvent a
constitutional provision or federal statute. Thomas v. Arn,
1
Some jurists have questioned this Court's supervisory authority over
lower courts. See, e.g., Western Pacifc R. Corp. v. Western Pacifc R.
Co., 345 U. S. 247, 273 (1953) (Jackson, J., dissenting) (questioning “this
Court's exercise of its vague supervisory powers over federal courts”);
Bank of Nova Scotia v. United States, 487 U. S. 250, 264 (1988) (Scalia, J.,
concurring) (“I do not see the basis for any direct authority to supervise
lower courts”). Others have questioned whether the courts of appeals
enjoy the same power. See, e. g., United States v. Strothers, 77 F. 3d 1389,
1397–1399 (CADC 1996) (Sentelle, J., concurring). The Government does
not challenge the general existence of the Court of Appeals' supervisory
power. See Tr. of Oral Arg. 11. Hence, we need not address that issue here.
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474 U. S. 140, 148 (1985). Nor can they confict with or cir-
cumvent
a Federal Rule. Carlisle v. United States, 517 U. S.
416, 426 (1996). Finally, and most relevant here, lower
courts cannot create prophylactic supervisory rules that cir-
cumvent or supplement legal standards set out in decisions
of this Court. United States v. Payner, 447 U. S. 727, 733–
737 (1980).
Payner exemplifes this last limit. There, a Federal Dis-
trict Court asserted supervisory power to suppress illegally
seized evidence even when the seizure violated a third par-
ty's Fourth Amendment rights, and the Court of Appeals
affrmed the decision. Id., at 733. This Court reversed,
explaining that its Fourth Amendment jurisprudence had
“established beyond any doubt” that a defendant could not
assert a third party's Fourth Amendment injury in order to
suppress evidence. Id., at 735. “Were we to accept this use
of the supervisory power,” the Court reasoned, “we would
confer on the judiciary discretionary power to disregard the
considered limitations of the law it is charged with enforc-
ing.” Id., at 737. Simply put, “the supervisory power does
not extend so far.” Ibid.
Nor does any supervisory power extend as the Court of
Appeals appears to suggest in this case. This Court has
held many times that a district court enjoys broad discretion
to manage jury selection, including what questions to ask
prospective jurors. See, e. g., Skilling, 561 U. S., at 387,
n. 20; Mu'Min, 500 U. S., at 427; Ristaino, 424 U. S., at 594;
Ham, 409 U. S., at 527; Connors, 158 U. S., at 413. As the
Court of Appeals acknowledged, our cases establish that a
reviewing court may set aside a district court's questioning
only for an abuse of discretion. See 968 F. 3d, at 56. The
Court of Appeals declined to apply that settled standard of
review. Rather than ask whether media-content questions
were necessary in light of the District Court's exhaustive
voir dire, the Court of Appeals resurrected Patriarca,
handed down a purported legal rule that media-content
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questions are required in all high-profle cases, and then
concluded
that the District Court committed a legal error
when it failed to comply with that rule. See 968 F. 3d, at
57–59. But a court of appeals cannot supplant the district
court's broad discretion to manage voir dire by prescribing
specifc lines of questioning, and thereby circumvent a well-
established standard of review. Whatever the “supervisory
power” entails, it does not countenance the Court of Appeals'
use of it.
B
The Court of Appeals' second reason for vacating Dzhok-
har's capital sentences—that the District Court erred in
excluding from the sentencing proceedings evidence of the
Waltham murders—fares no better.
The Federal Death Penalty Act (FDPA) sets out a compre-
hensive scheme by which federal district courts adjudicate,
review, and impose death sentences. See 18 U. S. C. §§ 3591
et seq. Section 3593 provides that, at the sentencing phase
of a capital trial, “information may be presented as to any
matter relevant to the sentence, including any mitigating or
aggravating factor.” § 3593(c). “Information is admissible
regardless of its admissibility under the rules governing ad-
mission of evidence at criminal trials.” Ibid.
That said, FDPA proceedings are not evidentiary free-
for-alls. The district court may exclude information under
the FDPA “if its probative value is outweighed by the dan-
ger of creating unfair prejudice, confusing the issues, or
misleading the jury.” Ibid. We review these evidentiary
exclusions for abuse of discretion. See, e. g., United States
v. Abel, 469 U. S. 45, 54 (1984); Sprint/United Management
Co. v. Mendelsohn, 552 U. S. 379, 384 (2008); 1 R. Mosteller
et al., McCormick on Evidence § 185, p. 1125 (8th ed. 2020).
Here, during sentencing, Dzhokhar sought to introduce
evidence linking Tamerlan to the unsolved Waltham mur-
ders. He argued that the evidence supported his mitigation
defense that Tamerlan was the ringleader. The District
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Court acknowledged Dzhokhar's rationale but excluded the
e
vidence because it was “without any probative value” and
“wou ld be confusi ng to the jury. ” App. 650. See 18
U. S. C. § 3593(c).
That conclusion was reasonable and not an abuse of the
District Court's discretion. Dzhokhar sought to divert the
sentencing jury's attention to a triple homicide that Tamer-
lan allegedly committed years prior, though there was no
allegation that Dzhokhar had any role in that crime. Nor
was there any way to confrm or verify the relevant facts,
since all of the parties involved were dead. As the District
Court explained, “there simply [was] insuffcient evidence to
describe [any] participation Tamerlan may have had” or
“tel[l] who played what role, if they played roles.” App.
650. The District Court did not abuse its discretion when
fnding that the evidence lacked probative value, would con-
fuse the jury, and ultimately would be nothing more than “a
waste of time.” Ibid.
Dzhokhar and the dissent offer several counterarguments,
none of which is convincing. First, Dzhokhar suggests that
§ 3593(c) violates the Eighth Amendment if its balancing test
operates to exclude any relevant mitigating evidence. See
Brief for Respondent 17, 31; Tr. of Oral Arg. 85–88. His
argument depends on a line of cases rooted in Lockett v.
Ohio, 438 U. S. 586 (1978), and Eddings v. Oklahoma, 455
U. S. 104 (1982),
2
which “requir[e] the sentencer to consider
mitigating circumstances when deciding whether to impose
the death penalty.” Jones v. Mississippi, 593 U. S. –––, –––
(2021). Dzhokhar suggests that a district court violates the
2
Some have argued that these cases and their progeny do not refect the
original meaning of the Eighth Amendment, whose prohibition “relates to
the character of the punishment, and not the process by which it is im-
posed.” Gardner v. Florida, 430 U. S. 349, 371 (1977) (Rehnquist, J., dis-
senting); see also, e. g., Miller v. Alabama, 567 U. S. 460, 505–506, and n. 3
(2012) (Thomas, J., dissenting). Neither party here asks us to revisit that
question and we decline to do so.
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Eighth Amendment under these precedents if it excludes
any
marginally relevant mitigating evidence that fails the
§ 3593(c) balancing test. See Tr. of Oral Arg. 85–88.
Our cases do not support Dzhokhar's extreme position.
“ `Lockett and its progeny stand only for the proposition that
a State may not cut off in an absolute manner the presenta-
tion of mitigating evidence, either by statute or judicial in-
struction, or by limiting the inquiries to which it is relevant
so severely that the evidence could never be part of the sen-
tencing decision at all.' ” Johnson v. Texas, 509 U. S. 350,
361 (1993) (quoting McKoy v. North Carolina, 494 U. S. 433,
456 (1990) (Kennedy, J., concurring in judgment)). We read
that principle to coexist with the overarching goal “that,
above all, capital sentencing must be reliable, accurate, and
nonarbitrary.” Saffe v. Parks, 494 U. S. 484, 493 (1990); ac-
cord, California v. Brown, 479 U. S. 538, 541 (1987). Thus,
“[o]ur capital sentencing jurisprudence seeks to reconcile
[these] two competing . . . principles”—“to allow mitigating
evidence to be considered and to guide the discretion of the
sentencer.” Johnson, 509 U. S., at 373. To effectively rec-
oncile these objectives, “[w]e need only conclude that it is
consistent with the Eighth Amendment for [the Federal Gov-
ernment] to channel the sentencer's consideration of a de-
fendant's arguably mitigating evidence so as to limit the rele-
vance of that evidence in any reasonable manner, so long as
the [Federal Government] does not deny the defendant a full
and fair opportunity to apprise the sentencer of all constitu-
tionally relevant circumstances.” Graham v. Collins, 506
U. S. 461, 498–499 (1993) (Thomas, J., concurring).
Because the States and the Federal Government “retain
`the traditional authority' ” “to decide that certain types of
evidence may have insuffcient probative value to justify
their admission,” they may enact reasonable rules governing
whether specifc pieces of evidence are admissible. Skipper
v. South Carolina, 476 U. S. 1, 11, 15 (1986) (Powell, J., con-
curring in judgment) (quoting Lockett, 438 U. S., at 604,
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n. 12 (plurality opinion)). Moreover, we have expressly held
that
“the Eighth Amendment does not deprive” a sovereign
“of its authority to set reasonable limits upon the evidence a
[capital] defendant can submit, and control the manner in
which it is submitted.” Oregon v. Guzek, 546 U. S. 517, 526
(2006).
Congress' passage of § 3593(c) falls well within that tradi-
tional authority. Section 3593(c) sets up a highly permissive
regime that allows criminal defendants to introduce a wide
range of normally inadmissible evidence. The statute chan-
nels that evidence through an individualized balancing test
that affords a capital defendant every reasonable opportu-
nity to place relevant mitigating evidence before the penalty-
phase jury. Unlike the statute challenged in Lockett or the
sentencer's decision challenged in Eddings, § 3593(c) does not
put any category of mitigating evidence beyond the sen-
tencer's purview. Rather, § 3593(c) preserves the traditional
gatekeeping function of district court judges to consider and
assess specifc pieces of relevant evidence in light of its pro-
bative value and the risks it poses to the jury's truth-seeking
function. The court weighs all proffered evidence to deter-
mine whether it will assist the jury in considering any
grounds for mitigation.
Put simply, § 3593(c) “does not deny the defendant a full
and fair opportunity to apprise the sentencer of all constitu-
tionally relevant circumstances. ” Graham, 506 U. S., at
498–499 (Thomas, J., concurring). It therefore does not of-
fend the Eighth Amendment.
Dzhokhar alternatively disagrees with the balance that the
District Court struck here under § 3593(c), arguing that the
Waltham evidence was “highly probative” to his mitigation
defense. Brief for Respondent 17 (emphasis deleted). On
his telling, the evidence showed that Tamerlan was a leader
who pressured others to commit violence. But the District
Court considered that argument and rejected it after reason-
ably explaining that “[t]here's just no way of telling who
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played what role, if they played roles,” from the sparse and
unrel
iable information before the court. App. 650. It was
“as plausible . . . that Todashev was the bad guy and Tamer-
lan was the minor actor.” Ibid. In other words, the evi-
dence did not tend to show that Tamerlan acted as the leader
who pressured Todashev into committing the crime. And it
certainly did not show that, almost two years later, Tamerlan
led and dominated Dzhokhar in a manner that would mitigate
Dzhokhar's guilt.
Dzhokhar further opines that he might have reduced juror
confusion by putting the information before the jury in a
“streamlined” manner. Brief for Respondent 32. But “[i]t
is important that a reviewing court evaluate the trial court's
decision from its perspective when it had to rule” rather than
“indulge in review by hindsight.” Old Chief v. United
States, 519 U. S. 172, 182, n. 6 (1997). Here, Dzhokhar did
not alert the District Court to any possible “streamlined”
approach, instead suggesting that, if the court admitted the
Waltham evidence, he would submit additional evidence and
possibly seek third-party discovery. Moreover, Dzhokhar
could not have unilaterally dictated how the proceeding
would progress because the Government would have been
“permitted to rebut any information received at the hearing ”
with evidence of its own. 18 U. S. C. § 3593(c). So no mat-
ter how Dzhokhar presented the evidence, its bare inclusion
risked producing a confusing mini-trial where the only wit-
nesses who knew the truth were dead. The District Court
did not abuse its discretion by declining to lead the jury into
this evidentiary detour.
Finally, Dzhokhar argues that since the Government ap-
parently considered Todashev's statement to the FBI agents
reliable enough to justify its reference in a search warrant
affdavit, Todashev's statements were necessarily reliable
enough to be presented to the jury as mitigating evidence.
See Brief for Respondent 27–28; see also post, at 334
(Breyer, J., dissenti ng) (contendi ng that the warrant
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“strongly suggests” the District Court abused its discretion).
W
e fail to see why. The District Court here did not sign
the warrant or the affdavit. Whatever probable-cause as-
sessment the FBI agent and the Magistrate Judge made, the
District Court was free to evaluate the information inde-
pendently when deciding whether to admit it under § 3593(c).
As explained, that evaluation was not an abuse of discretion.
For its part, the dissent subjects the District Court's deci-
sion to exclude the Waltham evidence to a more stringent
standard of review and, based on its independent review of
the record, would reverse. Post, at 331–342. While the dis-
sent acknowledges that district courts enjoy “signifcant dis-
cretion” when making evidentiary decisions, post, at 332, it
nevertheless argues that the death penalty context here re-
quires us to scrutinize the District Court's decision with
“particular judicial care,” post, at 341.
In doing so, the dissent ignores our traditional standard
for appellate review of evidentiary determinations.
3
Defer-
ence is the “hallmark of [the] abuse-of-discretion review” ap-
plicable to such decisions. General Elec. Co. v. Joiner, 522
3
None of the dissent's cases, see post, at 341–342, supports applying
heightened scrutiny to evidentiary decisions in death-penalty cases. The
language the dissent cites from Kyles v. Whitley, 514 U. S. 419, 422 (1995),
about our “ `duty to search for constitutional error,' ” post, at 341, in capital
cases is inapposite; it concerned our decision to grant review to engage in
fact-bound error correction, not the applicable standard for deciding
whether an error had in fact occurred. See 514 U. S., at 422, n. 1. Mean-
while, the language from Zant v. Stephens, 462 U. S. 862, 885 (1983), about
“careful scrutiny” concerned our review of the jury's “deliberative proc-
ess” leading to the imposition of a capital sentence, not the considered
evidentiary decisions of a District Court. Finally, Gregg v. Georgia, 428
U. S. 153, 187 (1976) ( joint opinion of Stewart, Powell, Stevens, JJ.), scruti-
nized whether procedural “safeguard[s]” were honored, not whether the
District Court's evidentiary rulings were substantively reasonable. All
told, not one of these cases addressed, let alone altered, the abuse-of-
discretion standard traditionally applicable to a district court's evidentiary
decisions. See General Elec. Co. v. Joiner, 522 U. S. 136, 141 (1997) (“We
have held that abuse of discretion is the proper standard of review of a
district court's evidentiary rulings”).
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U. S. 136, 143 (1997). A “reviewing court” applying that
st
andard “must not substitute its judgment for that of the
district court.” Horne v. Flores, 557 U. S. 433, 493 (2009)
(Breyer, J., dissenting). Rather, an appellate court must
defer to the lower court's “sound judgment,” so long as its
decision falls within its “wide discretion,” Abel, 469 U. S., at
54, and is not “ `manifestly erroneous,' ” Joiner, 522 U. S., at
142 (quoting Spring Co. v. Edgar, 99 U. S. 645, 658 (1879)).
Even in the death penalty context, this traditional abuse-of-
discretion standard applies.
Yet here, the dissent proposes to independently reevaluate
the District Court's decision to exclude the Waltham evi-
dence under § 3593(c). In particular, the dissent joins Dzhok-
har in critiquing the District Court's conclusion that the risk
of confusing the jury outweighed the probative value of that
evidence. See post, at 336–341. The dissent thinks it was
the “District Court's strongest reason” for excluding the evi-
dence, post, at 336, but it discounts the District Court's con-
clusion for two reasons. Neither is compelling, especially
under the deferential abuse-of-discretion standard.
First, the dissent suggests that because “death penalty
proceedings are special,” district courts should be more hesi-
tant to fnd a risk of confusion in this context than in others.
Post, at 337. But the dissent identifes nothing in the text
of the FDPA to support its position. Congress defned what
considerations district courts must balance when making ad-
missibility determinations under § 3593(c), and it chose to de-
fne one using a term familiar in the law of evidence—“con-
fusing the issues.” Compare § 3593(c) with Federal Rule of
Evidence 403; see also Mosteller, McCormick on Evidence
§ 185, at 1119 (noting “common law power of the judge to
exclude relevant evidence” to forestall “ `confusion of the is-
sues' ”). Nothing suggests that Congress intended district
courts to evaluate that concern differently under the FDPA.
Second, the dissent points out that district courts some-
times allow the Government to present evidence of a capital
defendant's past bad acts during sentencing proceedings, de-
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spite the risk of evidentiary minitrials. See post, at 338–
341.
But many of those cases focused on the defendant's
own conduct, not someone else's. See ibid. In such cases,
the Government need only put on evidence tending to show
that the defendant committed the past bad act. See, e. g.,
United States v. Umaña, 750 F. 3d 320, 348–349 (CA4 2014).
Here, the evidentiary showing would be substantially more
complex and confusing. No one alleges that Dzhokhar par-
ticipated in the Waltham murders, and, as the District Court
reasonably concluded, the evidence available sheds little light
on what role (if any) Tamerlan actually played. See App.
650. To make his point at sentencing, then, Dzhokhar would
frst have to show, without any surviving witnesses, what
role Tamerlan actually played. Then, he would have to es-
tablish that he learned of the Waltham crimes before plan-
ning the bombings. Finally, he would have to explain how
his knowledge of Tamerlan's role in a nearly 2-year-old vio-
lent robbery affected his own role in the bombings. What-
ever other courts might think about an inquiry into a defend-
ant's own prior bad acts, this District Court reasonably
thought that the Waltham murder inquiry risked confusing
the jury in these proceedings. We see no basis to disturb
that conclusion.
III
Dzhokhar Tsarnaev committed heinous crimes. The Sixth
Amendment nonetheless guaranteed him a fair trial before
an impartial jury. He received one. The judgment of the
United States Court of Appeals for the First Circuit is
reversed.
It is so ordered.
Justice Barrett, with whom Justice Gorsuch joins,
concurring.
In this case, the First Circuit asserted “supervisory
power” to impose a procedural rule on the District Court.

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Barrett, J., concurring
Because that rule (which required a district court to ask
media-content
questions on request in high-profle prosecu-
tions) conficts with our cases (which hold that a district
court has broad discretion to manage jury selection), I agree
with the Court that the First Circuit erred.
I write separately to note my skepticism that the courts
of appeals possess such supervisory power in the frst place.
Article III's grant of “[t]he judicial Power” imbues each
federal court with the inherent authority to regulate its
own proceedings. U. S. Const., Art. III, § 1; Chambers v.
NASCO, Inc., 501 U. S. 32, 43 (1991) (“It has long been under-
stood that `[c]ertain implied powers must necessarily result
to our Courts of justice from the nature of their institution,'
powers `which cannot be dispensed with in a Court, because
they are necessary to the exercise of all others' ” (quoting
United States v. Hudson, 7 Cranch 32, 34 (1812))). This au-
thority permits federal courts to handle a range of matters,
big and small, that fall in the gaps of governing statutes and
formally adopted procedural rules. See, e. g., Link v. Wa-
bash R. Co., 370 U. S. 626 (1962) (a district court can dismiss
a case sua sponte for failure to prosecute); Hazel-Atlas Glass
Co. v. Hartford-Empire Co., 322 U. S. 238 (1944) (a court of
appeals can vacate its judgment upon discovering fraud).
But here, the First Circuit did not adopt a rule regulat-
ing its own proceedings—it adopted a blanket rule that all
district courts in its jurisdiction must follow on pain of
reversal.
In fairness to the First Circuit, we have suggested that
the courts of appeals possess authority to dictate procedural
rules for district courts. See, e. g., Cuyler v. Sullivan, 446
U. S. 335, 346, n. 10 (1980) (citing Courts of Appeals decisions
requiring district courts to inquire into potential conficts of
interest and referring to this as “a desirable practice”); Cupp
v. Naughten, 414 U. S. 141, 146 (1973) (suggesting in dicta
that a court of appeals may require a district court “to follow

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procedures deemed desirable from the viewpoint of sound
judicia
l practice although in nowise commanded by statute
or by the Constitution”).* Understandably, then, the First
Circuit followed our lead. But before we go further down
this road, we should reexamine the map. Not only have we
failed to identify a source for this supposed authority, it is
unclear that any exists.
To be sure, this Court has squarely asserted supervisory
power to regulate procedure in lower federal courts. See
McNabb v. United States, 318 U. S. 332 (1943). While we
have not justifed this power either, it has an at least argu-
able basis: the Constitution's establishment of this Court as
“supreme,” as distinct from the “inferior Courts” that Con-
gress has discretion to create. Art. III, § 1. Much like the
grant of “[t]he judicial Power” carries with it inherent au-
thority over local procedure, this Court's designation as “su-
preme” might carry with it some inherent authority to pre-
scribe procedural rules for inferior federal courts. But see
ante, at 315, n. 1. In the end, this argument might be unsup-
ported by the Constitution's structure and history. Still, the
text of Article III makes it plausible.
*In dissent, Justice Breyer asserts that “our precedents clearly rec-
ognize the existence of ” the courts of appeals' supervisory power. Post,
at 342. But the cases cited by Justice Breyer refect our sometimes
imprecise use of the term “supervisory power.” Rather than using the
term to refer to a court of appeals' authority to impose procedures on an
inferior court, two of the cited cases use it to refer to a court's power to
“supervise” its own proceedings. See Ortega-Rodriguez v. United States,
507 U. S. 234, 249–250 (1993) (addressing a court of appeals' ability to dis-
miss an appeal of a former fugitive); Thomas v. Arn, 474 U. S. 140, 142
(1985) (a court of appeals may “establish a rule that the failure to fle
objections to the magistrate's report waives the right to appeal the district
court's judgment”). And in the third case, United States v. Hasting, 461
U. S. 499 (1983), the Court operated on the assumption that the Court of
Appeals had exercised “its supervisory powers to discipline the prosecu-
tors of its jurisdiction,” not to regulate district courts. Id., at 505 (empha-
sis added). The bottom line is that these cases do not address, much less
endorse, the kind of supervisory authority that the First Circuit asserted
here.

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Breyer, J., dissenting
Yet whatever the status of this Court's supervisory au-
thor
ity, it is diffcult, if not impossible, to fnd any comparable
constitutional hook for such power in the courts of appeals.
Nor does any statute grant them this general authority.
And while it is tempting to roll supervisory authority into
the power of appellate review, the two are analytically dis-
tinct. A court engaged in appellate review in this context
determines whether a lower court exceeded its inherent
authority to make a procedural choice. A court asserting
supervisory authority imposes its own procedural choice
on the lower court. In other words, supervisory author-
ity is not necessarily a lesser included power of appellate
review.
This case does not require us to resolve whether the courts
of appeals have supervisory authority over district courts.
Either way, the First Circuit erred. At some point in the
future, however, it would be worth revisiting our dicta.
Justice Breyer, with whom Justice Sotomayor and
Justice Kagan join except as to Part II–C, dissenting.
During the sentencing phase of his murder trial, Boston
Marathon bomber Dzhokhar Tsarnaev argued that he should
not receive the death penalty primarily on the ground that
his older brother Tamerlan took the leading role and induced
Dzhokhar's participation in the bombings. Dzhokhar ar-
gued that Tamerlan was a highly violent man, that Tamerlan
radicalized him, and that Dzhokhar participated in the bomb-
ings because of Tamerlan's violent infuence and leadership.
In support of this argument, Dzhokhar sought to introduce
evidence that Tamerlan previously committed three brutal,
ideologically inspired murders in Waltham, Massachusetts.
The District Court prohibited Dzhokhar from introducing
this evidence. The Court of Appeals held that the District
Court abused its discretion by doing so. 968 F. 3d 24, 73
(CA1 2020).
This Court now reverses the Court of Appeals. In my
view, the Court of Appeals acted lawfully in holding that the
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District Court should have allowed Dzhokhar to introduce
th
is evidence. See Lockett v. Ohio, 438 U. S. 586, 604 (1978)
(plurality opinion) (criminal defendant charged with capital
crime has constitutional right to present “any aspect of [his]
character or record and any of the circumstances of the of-
fense that the defendant proffers as a basis for a sentence
less than death”); Eddings v. Oklahoma, 455 U. S. 104, 110
(1982) (adopting Lockett's plurality rule). Consequently, I
dissent.
I
During the guilt phase of Dzhokhar's trial, Dzhokhar ac-
knowledged that he participated in the Boston Marathon
bombings. He conceded that he and his older brother Tam-
erlan planted bombs along the route of the Patriot's Day
Marathon and that the bombs killed or injured many inno-
cent people. Given Dzhokhar's concession, his trial focused
almost exclusively on sentencing, in particular whether
Dzhokhar should receive the death penalty. Dzhokhar ar-
gued in mitigation that his conduct was less serious than
Tamerlan's and that Tamerlan's radicalizing infuence was a
major reason that Dzhokhar participated in the bombings.
See Sears v. Upton, 561 U. S. 945, 950 (2010) (per curiam)
(older brother's criminal record and introduction of defend-
ant “to a life of crime” supported mitigation theory that de-
fendant “may have desired to follow in the footsteps” of his
older brother); Lockett, 438 U. S., at 608 (“defendant's com-
paratively minor role in the offense” is relevant mitigating
factor).
In support of this theory, the District Court allowed
Dzhokhar to argue that: (1) Dzhokhar “acted under the in-
fuence of his older brother” Tamerlan; (2) Dzhokhar “would
not have committed the crimes but for [his] older brother
Tamerlan”; (3) Dzhokhar “was particularly susceptible to his
older brother's infuence,” “[w]hether because of Tamerlan's
age, size, aggressiveness, domineering personality, privi-
leged status in the family, traditional authority as the eldest
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329
Breyer, J., dissenting
brother, or other reasons”; (4) Tamerlan “planned, led, and
direc
ted the Marathon bombing ”; and (5) Tamerlan “became
radicalized frst, and then encouraged his younger brother to
follow him.” App. 614, 616 (boldface omitted). The Dis-
trict Court also allowed Dzhokhar to introduce certain evi-
dence in support of this mitigation theory. This included
evidence that Tamerlan had behaved aggressively in the
past, and that Dzhokhar looked up to Tamerlan. But the
court did not allow Dzhokhar to introduce evidence of Tam-
erlan's participation in the Waltham murders.
The “Waltham murders” refers to the killing of three drug
dealers in Waltham, Massachusetts. The murders took
place on September 11, 2011, the 10th anniversary of the
9/11 terrorist attacks, and about a year and a half before the
Boston Marathon bombings. The evidence relating to the
Waltham murders came primarily from FBI agent inter-
views of Ibragim Todashev, a friend of Tamerlan's. During
the FBI interviews, Todashev (who attacked the agents and
was killed midinterview) initially denied participating in the
murders but later said that he and Tamerlan had com-
mitted them.
In particular, Todashev said that it was Tamerlan's idea to
rob the drug dealers, one of whom was Tamerlan's close
friend. Todashev said that they both went to the drug deal-
ers' house, threatened the drug dealers at gun point, bound
them with duct tape, and searched the house for money.
Tamerlan then beat up the dealers and, in an attempt to get
more money, threatened to stab them. Todashev also said
that Tamerlan insisted on killing the drug dealers (even
though Todashev “ `begged him not to' ”), and that Todashev,
feeling like he had no “way out,” waited outside the house
while Tamerlan slit their throats. Id., at 915, 948. Finally,
Todashev said that Tamerlan called him back inside to help
clean up after the drug dealers were dead and that the two
left with about $40,000 of stolen money.
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The FBI relied on Todashev's statements to obtain a
search
warrant for Tamerlan's car, which agents believed
was the car used to drive to and from the drug dealers'
house. An FBI affdavit attached to the search warrant re-
quest stated that Todashev had
“confessed that he and Tamerlan participated in the
Waltham murders. He said that he and Tamerlan had
agreed initially just to rob the victims, whom they knew
to be drug dealers . . . . Todashev said that Tamerlan
had a gun, which he brandished to enter the residence.
Tamerlan decided that they should eliminate any wit-
nesses to the crime, and then Todashev and Tamerlan
bound the victims, who were ultimately murdered.”
Id., at 998.
Based on this and other less signifcant evidence, the FBI
agent asserted that there was “probable cause to believe that
Todashev and Tame[rl]an planned and carried out” the Wal-
tham Murders. Id., at 996. A federal judge agreed, and
issued a warrant.
Other evidence uncovered during the FBI's investigation
of the Boston Marathon bombings also related to the Wal-
tham murders. Dias Kadyrbayev, a friend of Dzhokhar's,
stated that a few months before the bombings Dzhokhar
learned of Tamerlan's involvement in the Waltham murders.
Kadyrbayev said that Dzhokhar described Tamerlan's partic-
ipation in the murders as “ `commit[ting] jihad.' ” Id., at 584.
Investigators also found al Qaeda propaganda on Tamerlan's
computer that advocated stealing money from non-Muslims
as a way to support jihadist principles.
Dzhokhar was prohibited from introducing any of this evi-
dence during the sentencing phase of his trial. At the end of
his sentencing proceeding, and without hearing any evidence
about the Waltham murders, eight jurors found that Tamer-
lan had become radicalized before Dzhokhar and encouraged
Dzhokhar to follow his example. Id., at 616. Three found

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331
Breyer, J., dissenting
that Tamerlan planned, led, and directed the bombings. Id.,
at
614. Three also found that Dzhokhar acted under Tamer-
lan's infuence, that he was particularly susceptible to Tamer-
lan's infuence, and that he would not have committed the
bombings but for Tamerlan. Ibid. The jury nonetheless
unanimously recommended the death penalty for Dzhokhar
in respect to those counts involving the bomb that he him-
self—and he alone—had placed. The District Court then
sentenced Dzhokhar to death.
Dzhokhar appealed. As the Court explains, the Court of
Appeals held that the District Court had to conduct a new
sentencing proceeding for two independent reasons. Ante,
at 311–312. First, the trial court had not adequately ques-
tioned potential jury members about the content of the pre-
trial publicity they had seen. Second, the trial court did not
permit Dzhokhar to introduce evidence about the Waltham
murders during the sentencing phase of his trial. I disagree
with the Court's decision (and I agree with the Court of Ap-
peals) at least as to the second reason.
II
A
The Federal Death Penalty Act sets forth the legal stand-
ards governing the admissibility of mitigating evidence dur-
ing a capital sentencing. See 18 U. S. C. § 3591 et seq. The
statute provides an admissibility standard unique to death
penalty cases. It says that in death penalty sentencing pro-
ceedings, “information may be presented as to any matter
relevant to the sentence, including any mitigating or aggra-
vating factor.” § 3593(c). And that is so whether that “in-
formation” is or is not admissible “under the rules governing
admission of evidence at criminal trials.” Ibid. The stat-
ute also provides that a trial court “may” exclude evidence
“if its probative value is outweighed by the danger of creat-
ing unfair prejudice, confusing the issues, or misleading the
jury.” Ibid.
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As the majority points out, district courts have signifcant
discreti
on in deciding how to apply and weigh the statute's
factors. Ante, at 317–319. But “abuse-of-discretion review
is not toothless; and it is entirely proper for a reviewing
court to fnd an abuse of discretion when important fac-
tors . . . are `slighted.' ” Gall v. United States, 552 U. S.
38, 72 (2007) (Alito, J., dissenting) (quoting United States v.
Taylor, 487 U. S. 326, 337 (1988)); see also American Paper
Institute, Inc. v. American Elec. Power Service Corp., 461
U. S. 402, 413 (1983) (to decide whether action was abuse of
discretion, “we must determine whether the [court] ade-
quately considered the factors relevant” to the question);
Highmark Inc. v. Allcare Health Management System, Inc.,
572 U. S. 559, 563, n. 2 (2014) (“The abuse-of-discretion stand-
ard does not preclude an appellate court's correction of a dis-
trict court's . . . clearly erroneous assessment of the evi-
dence” (internal quotation marks omitted)). And here, we
review for abuse of discretion in the context of “a matter so
grave as the determination of whether a human life should
be taken or spared.” Gregg v. Georgia, 428 U. S. 153, 189
(1976) ( joint opinion of Stewart, Powell, and Stevens, JJ.). I
therefore apply the standard with care. Cf. id., at 187
(“When a defendant's life is at stake, the Court has been
particularly sensitive to insure that every safeguard is ob-
served”); Zant v. Stephens, 462 U. S. 862, 885 (1983) (“[T]he
severity of the [capital] sentence mandates careful scrutiny
in the review of any colorable claim of error”).
The District Court here excluded the Waltham evidence
for the following four reasons:
“[T]here simply is [1] insuffcient evidence to describe
what participation Tamerlan may have had in those
events. . . . From my review of the evidence, . . . it is as
plausible, which is not very, that Todashev was the bad
guy and Tamerlan was the minor actor. There's just no
way of telling who played what role, if they played roles.
So it simply would be [2] confusing to the jury and [3] a
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333
Breyer, J., dissenting
waste of time, I think, without very—[4] without any
probative
value.” App. 650.
I have reviewed the record keeping in mind the reasons the
District Court gave: (1) no probative value; (2) insuffcient
evidence to corroborate Tamerlan's role in the murders;
(3) waste of time; and (4) jury confusion. Reading the rec-
ord in light of these factors, I believe that the Court of Ap-
peals was correct that the District Court abused its discre-
tion by excluding the Waltham evidence. The record does
not adequately support exclusion for the District Court's
stated reasons.
Consider the factors that the District Court directly and
indirectly took into account.
1. Relevance/Probative Value
The District Court was wrong when it described the
Waltham evidence as lacking “any probative value.” The
evidence met the “threshold for relevance” applicable here.
Tennard v. Dretke, 542 U. S. 274, 285 (2004); id., at 284 (“Rel-
evant mitigating evidence is evidence which tends logically
to prove or disprove some fact or circumstance which a fact-
fnder could reasonably deem to have mitigating value”
(internal quotation marks omitted)). And it possessed pro-
bative value.
The Waltham evidence tended to show that Tamerlan was
involved in a brutal triple murder, possibly over Todashev's
objections, a year and a half before the bombings. The evi-
dence tended to show that Tamerlan committed these mur-
ders for ideological reasons. This is true (though to a lesser
degree) even if Tamerlan played a secondary, rather than
the primary, role in the Waltham killings. Evidence that
Tamerlan participated in (and potentially orchestrated) one
set of ideologically motivated murders in 2011 supports the
claim that Tamerlan was the violent, radicalizing force be-
hind the ideologically motivated bombings a year and a half
later.
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2. Corroboration/Reliability
The
Waltham evidence was corroborated and suffciently
reliable to warrant presentation to the jury. Dzhokhar's
friend Kadyrbayev said that Dzhokhar believed Tamerlan
was involved in the Waltham killings. Kadyrbayev also said
that Dzhokhar told him that Tamerlan “had committed jihad”
in Waltham. Relatedly, Tamerlan had al Qaeda propaganda
on his computer that advocated stealing money from non-
Muslims as a way to support jihadist principles. There was
also evidence that a week or so after the Waltham killings,
someone ran internet searches on Tamerlan's wife's com-
puter for “3 men killed in Waltham,” “men kill in Waltham,”
and “tamerlan tsarnaev.” App. 590. Tamerlan's wife also
confrmed that Tamerlan was close friends with one of the
drug dealers, and there was evidence that Tamerlan did not
attend that friend's funeral, which some thought strange
given their close relationship.
Further, the Waltham evidence was suffciently reliable for
the Government to conclude (via FBI affdavit) that it helped
to establish probable cause that Tamerlan committed the
Waltham murders. It was reliable enough for a federal
judge to issue a search warrant for Tamerlan's car to look
for evidence of those murders. It is of course true, as the
majority points out, that the District Court was free to make
an independent assessment of the reliability of the evidence.
Ante, at 321–322. But the fact that both the Government
and a federal judge found the evidence suffciently reliable
to establish probable cause that Tamerlan committed the
murders strongly suggests that the District Court here
abused its discretion in concluding that the same evidence
was so unreliable that Dzhokhar could not use it as mitigat-
ing evidence to establish the same proposition. Cf. Florida
v. Harris, 568 U. S. 237, 243 (2013) (probable cause exists
when facts “would warrant a person of reasonable caution in
the belief that contraband or evidence of a crime is present”
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335
Breyer, J., dissenting
(internal quotation marks and brackets omitted; emphasis
added)).
3.
Waste of Time/Need
The Waltham evidence was not simply cumulative of other
mitigation evidence. And it was critically important to
Dzhokhar's mitigation defense. Apart from the Waltham
evidence, the evidence of Tamerlan's aggressive nature and
violent tendencies consisted of evidence showing (1) that
Tamerlan physically abused his then-girlfriend (later wife);
(2) that he twice became disruptive and shouted at an Imam
during prayers; (3) that he poked someone in the chest dur-
ing an argument; (4) that he punched a man in the street
after the man said something Tamerlan did not like; (5) that
Tamerlan yelled at a local butcher who was selling halal tur-
key for Thanksgiving; and (6) that Tamerlan was disruptive
at his boxing gym. Participation in a robbery and triple
murder is much stronger evidence of Tamerlan's violent na-
ture than any of these incidents. Cf. Skipper v. South Caro-
lina, 476 U. S. 1, 8 (1986) (reversible error where excluded
mitigating evidence had “greater weight” than evidence sup-
porting same mitigating factors).
Similarly, the evidence introduced to show Tamerlan's in-
fuence over Dzhokhar consisted of evidence showing (1)
their age difference (Tamerlan was 26 at the time of the
bombings, Dzhokhar 19); (2) the fact that Dzhokhar looked
up to and followed his older brother; (3) that in the brothers'
Chechen culture, Tamerlan, as the older sibling, held a posi-
tion of authority and superiority vis-à-vis Dzhokhar; (4) that
Tamerlan sent Dzhokhar articles containing extremist propa-
ganda; and (5) that Tamerlan traveled to Russia in 2012 as
part of an unsuccessful effort to wage “jihad.” But the Wal-
tham evidence showed (if the jury believed Todashev's ac-
count) that Tamerlan had previously exerted such infuence
over Todashev as to make him an unwilling accomplice to a
triple murder. This is much stronger evidence of Tamer-
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lan's capacity to infuence than any evidence that the jury
heard.
Moreover
, Dzhokhar had particular need for the Waltham
evidence in the context of his sentencing. As both counsel
emphasized during closing argument, the critical mitigation
issue was the two brothers' comparative responsibility.
Dzhokhar's counsel argued, for example, that “if not for Tam-
erlan, this wouldn't have happened. Dzhokhar would never
have done this but for Tamerlan.” App. 839–840. The
prosecution similarly told the jury that “the bulk of [Dzhok-
har's] mitigation case comes down to a single proposition:
`His brother made him do it.' ” Id., at 857. The prosecution
also told the jury that it should reject this proposition be-
cause Dzhokhar's mitigation evidence merely showed that
Tamerlan was “loud,” “bossy,” and “sometimes lost his tem-
per.” Id., at 861, 864. Would the prosecution have made
the same argument had the evidence required it to add, “and
perhaps slit the throats of three people”? Cf. Clemons v.
Mississippi, 494 U. S. 738, 753 (1990) (erroneous jury instruc-
tion reversible error where “repeatedly emphasized and ar-
gued” by prosecution); Skipper, 476 U. S., at 5, n. 1 (exclusion
of evidence reversible error when evidence related to issue
“underscored . . . by the prosecutor's closing argument”).
The prosecution went on to argue that Tamerlan and
Dzhokhar were “equals,” and that it was only once Dzhokhar
“made the decision to become a terrorist, that Tamerlan was
able to go into action.” App. 873–874. Would the prosecu-
tion have made that same claim in the face of evidence that
Tamerlan had taken “action” a year and a half before the
bombings, on the anniversary of 9/11, and that Dzhokhar
characterized this action as “jihad”? The excluded evidence
went to the heart of these critical sentencing issues.
4. Jury Confusion
In my view, the District Court's strongest reason for ex-
cluding the Waltham evidence, and the majority's best argu-
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337
Breyer, J., dissenting
ment for reversing the Court of Appeals, is that admitting
the
evidence might have confused the jurors by prompting a
“minitrial” about what actually happened in Waltham and
what role Tamerlan played. The Federal Death Penalty Act
says that a court “may” exclude relevant evidence “if its pro-
bative value is outweighed by the danger of . . . confusing the
issues, or misleading the jury.” § 3593(c). Given the trial
judge's discretionary authority to admit or exclude evidence,
could the possibility of juror confusion overcome the pro-
admission factors I have so far discussed? Two reasons
convince me that it could not, and that, concerns about jury
confusion notwithstanding, the District Court abused its dis-
cretion by excluding the evidence.
First, death penalty proceedings are special. Unlike evi-
dentiary determinations made in other contexts, a trial
court's decision to admit or exclude evidence during a capital
sentencing proceeding is made against the backdrop of a cap-
ital defendant's constitutional right to argue against the
death penalty. See Tennard, 542 U. S., at 285 (“[T]he
Eighth Amendment requires that the jury be able to con-
sider and give effect to a capital defendant's mitigating evi-
dence” (internal quotation marks omitted)). So, although
the Federal Death Penalty Act incorporates some of the fea-
tures that ordinarily guide a trial judge's discretionary deci-
sion to admit or exclude evidence, see Fed. Rule Evid. 403,
it also provides a special admissibility standard unique to
the capital sentencing context. Specifcally, the statute says
that “information may be presented as to any matter rele-
vant to the sentence, including any mitigating or aggravating
factor,” regardless of whether that information would be ad-
missible under normal evidentiary rules. § 3593(c) (empha-
sis added). The statute thus tips the balance in favor of
admitting mitigating evidence, even if admission means
increasing the length of a proceeding by inviting some “mini-
trials” over subsidiary issues. Cf. McKoy v. North Caro-
lina, 494 U. S. 433, 442 (1990) (“The Constitution requires
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States to allow consideration of mitigating evidence in capi-
t
al cases”); see also Smith v. Texas, 543 U. S. 37, 44 (2004)
(per curiam). This weighted scale makes sense in the con-
text of capital proceedings, in a way it would not make sense
in run-of-the-mill evidentiary disputes, “[g]iven that the im-
position of death . . . is so profoundly different from all other
penalties.” Lockett, 438 U. S., at 605 (plurality opinion).
Indeed, because “the penalty of death is qualitatively differ-
ent from” all other punishments, “there is a corresponding
difference in the need for reliability in the determination
that death is the appropriate punishment in a specifc case.”
Woodson v. North Carolina, 428 U. S. 280, 305 (1976) (plural-
ity opinion). And a jury's decision to impose the death pen-
alty is more reliable if it is made after considering relevant
mitigation evidence that counsels against imposing such a
sentence. See Lockett, 438 U. S., at 605 (emphasizing the
need in capital cases to give “independent mitigating weight
to aspects of the . . . circumstances of the offense proffered
in mitigation”).
At the same time, a trial judge normally can control the
presentation of evidence to avoid unwarranted detours and
to ensure a trial does not extend beyond reasonable limits.
See, e. g., Fed. Rule Evid. 105 (court can instruct jury that it
may consider evidence for one purpose but not another); Ged-
ers v. United States, 425 U. S. 80, 86–87 (1976) (“Within lim-
its, the judge . . . may refuse to allow cumulative, repetitive,
or irrelevant testimony, and may control the scope of exami-
nation of witnesses” (citations omitted)). In the context of
capital sentencing, then, concerns about juror “waste of
time” or the risk of “confusion” are less justifable bases on
which to exclude an entire category of evidence that may
have signifcant mitigating value.
Second, and perhaps of greater importance, a sampling of
other death penalty proceedings indicates that the prosecu-
tion often introduces evidence of a defendant's prior criminal
behavior in support of the death penalty, including evidence
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339
Breyer, J., dissenting
that poses a similar risk of jury confusion. Trial judges
admit
this evidence under the same admissibility standard
that governs the admission of mitigating evidence. See
§ 3593(c) (governing admissibility of evidence supporting
“aggravating,” as well as “mitigating,” factors). And trial
courts admit this evidence not because the defendant's past
criminal behavior is directly relevant to the crime at issue
but because it supports an “aggravating ” death-penalty-
related factor such as a defendant's risk of future dangerous-
ness. If courts admit evidence of past criminal behavior,
unrelated to the crime at issue, to show aggravating circum-
stances, why should they not do the same to show mitigat-
ing circumstances?
Moreover, capital sentencing courts routinely admit this
kind of evidence even if the past criminal behavior did not
result in formal charges or convictions (and thus has not been
proved to a jury or judge). See, e. g., United States v. Ga-
brion, 719 F. 3d 511, 518 (CA6 2013) (District Court admitted
evidence of defendant's “likely role in the disappearance (and
presumably murder) of three other people”); United States
v. Runyon, 707 F. 3d 475, 504–505 (CA4 2013) (District Court
did not abuse its discretion in admitting evidence of defend-
ant's assault charges that were later dismissed); United
States v. Snarr, 704 F. 3d 368, 395 (CA5 2013) (District Court
admitted evidence that defendant “participated in a drive-by
shooting and allegedly murdered a man”); United States v.
Lighty, 616 F. 3d 321, 341 (CA4 2010) (District Court ad-
mitted evidence that defendant was involved in driveby
shooting for which he was never charged); United States v.
Brown, 441 F. 3d 1330, 1368 (CA11 2006) (District Court ad-
mitted evidence that “defendant has committed an array of
other criminal acts, some but not all of which have resulted
in conviction”).
Further, trial courts admit this evidence despite claims
that the evidence is not reliable (thus risking “minitrials”).
See, e. g., United States v. Coonce, 932 F. 3d 623, 641 (CA8
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2019); United States v. Umaña, 750 F. 3d 320, 348–349 (CA4
2014);
United States v. Hager, 721 F. 3d 167, 201 (CA4 2013);
United States v. Higgs, 353 F. 3d 281, 323 (CA4 2003).
The evidentiary showing Dzhokhar attempted to make
here was not, as the majority asserts, any more complex or
confusing than the evidentiary showing the Government
makes in these situations. Cf. ante, at 324. To the contrary,
just as the Government introduces evidence of a defendant's
prior unproved bad conduct to show a defendant's danger-
ousness, so too did Dzhokhar seek to introduce evidence of
Tamerlan's prior unproved bad conduct to show Tamerlan's
dangerousness. The fact that the evidence was about Tam-
erlan's character instead of Dzhokhar's did not render the
evidence beyond the jury's ability to comprehend. The Dis-
trict Court implicitly recognized as much when it allowed
Dzhokhar to introduce other evidence of Tamerlan's past
conduct—conduct in which Dzhokhar did not participate.
Indeed, this Court has rejected concerns that distracting
minitrials should preclude the Government from introducing
evidence about a nondefendant third party to show aggrava-
tion. See Payne v. Tennessee, 501 U. S. 808, 823 (1991) (re-
jecting reasoning that victim impact evidence should be ex-
cluded from sentencing proceeding because it would “creat[e]
a mini-trial on the victim's character” (internal quotation
marks omitted)). Why then should the same concern pre-
clude a defendant from introducing similar evidence in miti-
gation? After all, the Government, unlike a defendant, has
no constitutional right to present evidence during a capital
sentencing proceeding. Cf. Tennard, 542 U. S., at 285
(“[T]he Eighth Amendment requires that the jury be able to
consider and give effect to a capital defendant's mitigating
evidence” (internal quotation marks omitted)).
I conclude, then, that the reasons the District Court gave
do not justify excluding the Waltham murder evidence, and
it was an abuse of discretion to do so. Nor was the exclusion
harmless. See § 3595(c)(2)(C) (death sentence can be va-
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341
Breyer, J., dissenting
cated if Government fails to prove beyond a reasonable doubt
that
an error was harmless). Dzhokhar conceded his guilt.
The only issue was whether he deserved to die. Tellingly,
the jury's nuanced verdict refected close attention to the
relationship between the brothers: The jury did not recom-
mend the death penalty for the charges related to the ac-
tions Dzhokhar took together with Tamerlan, and only rec-
ommended death for the charges related to the actions
Dzhokhar took alone. The Waltham evidence supported
Dzhokhar's theory that Tamerlan's violent and radicalizing
infuence induced all of the actions Dzhokhar took in connec-
tion with the Boston Marathon bombings. This evidence
may have led some jurors to conclude that Tamerlan's infu-
ence was so pervasive that Dzhokhar did not deserve to die
for any of the actions he took in connection with the bomb-
ings, even those taken outside of Tamerlan's presence. And
it would have taken only one juror's change of mind to have
produced a sentence other than death, even if a severe one.
See § 3593(e) (death verdict must be unanimous).
B
Three courts including this Court have now examined this
record with care. Why? Why are appellate courts so
deeply involved in what is, after all, a trial-based evidentiary
matter? The reason, in my view, lies in part in the nature
of the underlying proceeding. It is a death penalty proceed-
ing. And where death is at stake, the courts (and Congress)
believe that particular judicial care is required. See § 3593
(detailing unique procedures applicable to the “[s]pecial hear-
ing to determine whether a sentence of death is justifed”
(boldface omitted)); Cf. Kyles v. Whitley, 514 U. S. 419, 422
(1995) (“[O]ur duty to search for constitutional error with
painstaking care is never more exacting than it is in a capital
case” (internal quotation marks omitted)); Zant, 462 U. S., at
885 (“[T]he severity of the [death] sentence mandates careful
scrutiny in the review of any colorable claim of error”);
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Gregg, 428 U. S., at 187 ( joint opinion) (“When a defendant's
l
ife is at stake, the Court has been particularly sensitive to
insure that every safeguard is observed”); Glossip v. Gross,
576 U. S. 863, 937 (2015) (Breyer, J., dissenting) (“[I]t is
diffcult for judges, as it would be diffcult for anyone, not
to apply legal requirements punctiliously when the conse-
quences of failing to do so may well be death”). That same
care applies on abuse-of-discretion review, just as it does for
any other standard. The extra time that close examination
takes is part of the procedural price that a judicial system
allowing the death penalty will inevitably exact.
C
I have written elsewhere about the problems inherent in
a system that allows for the imposition of the death penalty.
See, e. g., id., at 909–938. This case provides just one more
example of some of those problems.
III
In my view, the Court of Appeals was correct in its Wal-
tham evidence conclusion. For that reason, the District
Court should conduct a new sentencing proceeding. I need
not, and do not, reach the pretrial publicity question. I
note, however, that when considering that issue, the Court
refers to the power of the federal appeals courts to promul-
gate supervisory rules. See ante, at 315. Like the Court
(and Justice Barrett), I recognize that the Government
“does not challenge the general existence of the Court of
Appeals' supervisory power.” Ibid., n. 1. I would add that
our precedents clearly recognize the existence of such a
power. See, e. g., Thomas v. Arn, 474 U. S. 140, 146 (1985)
(“It cannot be doubted that the courts of appeals have super-
visory powers that permit, at the least, the promulgation of
procedural rules governing the management of litigation”);
United States v. Hasting, 461 U. S. 499, 505 (1983) (“[I]n the
exercise of supervisory powers, federal courts may, within
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as: 595 U. S. 302 (2022)
343
Breyer, J., dissenting
limits, formulate procedural rules not specifcally required
by
the Constitution or the Congress”). I would also add
that “[o]ur review of rules adopted by the courts of appeals”
pursuant to th is power “ is l i mited i n scope. ” O r tega-
Rodriguez v. United States, 507 U. S. 234, 244 (1993). And
I do not fnd that surprising. A degree of authority for the
courts of appeals, closer to the fray, to issue at least some
supervisory rules facilitates the fexibility needed in our geo-
graphically dispersed multicircuit system.
***
For these reasons, with respect, I dissent.
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Reporter’s Note
The attached opinion has been revised to refect the usual publication
and citation style of the United States Reports. The revised pagination
makes available the offcial United States Reports citation in advance of
publication. The syllabus has been prepared by the Reporter of Decisions
for the convenience of the reader and constitutes no part of the opinion of
the Court. A list of counsel who argued or fled briefs in this case, and
who were members of the bar of this Court at the time this case was
argued, has been inserted following the syllabus. Other revisions may
include adjustments to formatting, captions, citation form, and any errant
punctuation. The following additional edits were made:
p. 304, line 13, the second occurrence of “the” is deleted
p. 305, lines 4–5, “in which “Kagan, J., joined, and in which Sotomayor,
J., joined except as to Part II–C” is changed to “in which Sotomayor
and Kagan, JJ., joined except as to Part II–C”
p. 320, line 1, “n. 12” is changed to “n. 12 (plurality opinion)”