(Slip Opinion) OCTOBER TERM, 2021 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

UNITED STATES v. TSARNAEV

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR 

THE FIRST 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 finish

line of the Boston Marathon, killing three and wounding hundreds. 

Three days later, as investigators began to close in, the brothers fled. 

In the process, they murdered a Massachusetts Institute of Technology 

campus police officer, 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 prospective 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 

Government asked the trial court to exclude any reference to the Wal-
2 UNITED STATES v. TSARNAEV

Syllabus

tham murders on the grounds that the evidence either lacked relevance or, alternatively, lacked probative value and was likely to confuse the issues. The Government also pointed out that, because FBI 

agents had killed Todashev in self-defense after he attacked them during the interview, 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 discretion 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 sentences. Pp. 8–20.

(a) The District Court did not abuse its discretion by declining to ask 

about the content and extent of each juror’s media consumption regarding 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 significant 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 remaining 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 

prospective jurors. The District Court then subjected those remaining 

prospective jurors to three weeks of individualized voir dire, including 

questions that probed for bias. Finally, the court instructed the prospective 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 District 
Cite as: 595 U. S. ____ (2022) 3

Syllabus

Court, as a matter of law, to ask the jurors that specific question. The 

supervisory power of federal courts, however, does not extend to the 

creation of prophylactic supervisory rules that circumvent or supplement legal standards set out in decisions of this Court. See United 

States v. Payner, 447 U. S. 727, 733–737. Pp. 8–13.

(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 

U. S. C. §3593(c). But the district court may exclude information “if 

its probative value is outweighed by the danger of creating unfair prejudice, confusing the issues, or misleading the jury.” Ibid. Such evidentiary 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 mitigation defense that Tamerlan was the ringleader of the 

bombing. That evidence, however, did not allow the jury to confirm or 

assess Tamerlan’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 the Federal Government’s “‘traditional authority’” “to decide that 

certain types of evidence may have insufficient probative value to justify their admission,” Skipper v. South Carolina, 476 U. S. 1, 11, 15 

(Powell, J., concurring 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 introduce 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 evidence 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 significant 

discretion over its evidentiary decisions. But because this is a death 

penalty case, the dissent scrutinizes those decisions with particular 

care to find that the District Court abused its discretion. In doing so, 
4 UNITED STATES v. TSARNAEV 

 

Syllabus 

the dissent 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 specifically, the dissent suggests that a district court presiding over death-penalty proceedings 

should be more hesitant to find 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 evidence under §3593(c)’s balancing test. Pp. 13–20. 

968 F. 3d 24, reversed. 

 THOMAS, J., delivered the opinion of the Court, in which ROBERTS, C. J., 

and ALITO, GORSUCH, KAVANAUGH, and BARRETT, JJ., joined. BARRETT, 

J., filed a concurring opinion, in which GORSUCH, J., joined. BREYER, J., 

filed a dissenting opinion, in which SOTOMAYOR and KAGAN, JJ., joined 

except as to Part II–C. 
Cite as: 595 U. S. ____ (2022) 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, Washington, 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

_________________

No. 20–443

_________________

UNITED STATES, PETITIONER v.

DZHOKHAR A. TSARNAEV

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE FIRST CIRCUIT

[March 4, 2022]

JUSTICE THOMAS delivered the opinion of the Court.

On April 15, 2013, Dzhokhar and Tamerlan Tsarnaev 

planted and detonated two homemade pressure-cooker 

bombs near the finish line of the Boston Marathon. The 

blasts hurled nails and metal debris into the assembled 

crowd, killing three while maiming and wounding hundreds. Three days later, the brothers murdered a campus 

police officer, carjacked a graduate student, and fired on police who had located them in the stolen vehicle. Dzhokhar 

attempted to flee in the vehicle but inadvertently killed 

Tamerlan by running him over. Dzhokhar was soon arrested and indicted.

A jury found Dzhokhar guilty of 30 federal crimes and 

recommended 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 
2 UNITED STATES v. TSARNAEV

Opinion of the Court

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 Marathon finish 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 

backpack outside the Forum, a nearby restaurant where 

spectators 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 

backpack 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 seconds, he detonated his bomb.

Each detonation sent fire and shrapnel in all directions. 

The blast from Tamerlan’s bomb shattered Krystle Campbell’s left femur and mutilated her legs. Though bystanders 

tried to save her, she bled to death on the sidewalk. Dzhokhar’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.

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 burns. Martin ultimately died from blood loss.

Dzhokhar’s and Tamerlan’s bombs maimed and wounded 

hundreds of other victims. Many people lost limbs, including Martin’s 6-year-old sister, Jane. Many more would 
Cite as: 595 U. S. ____ (2022) 3

Opinion of the Court

have died if not for the swift action of citizens and first responders.

After fleeing the scene, the brothers returned to their normal 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 Investigation (FBI) released images of the suspected bombers, a 

friend saw the images and texted Dzhokhar. Dzhokhar responded: “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 brothers 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-yearold campus police officer Sean Collier sitting in his patrol 

car. They approached his car and shot him five 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 fled on foot. The 

brothers briefly chased him but gave up and made off with 

Meng’s SUV.

Meng contacted the police, who used the SUV’s GPS device to track the Tsarnaevs. When officers found the brothers in Watertown a few hours later, a street battle ensued. 

Tamerlan fired on the officers with a handgun, while Dzhokhar threw homemade bombs. When Tamerlan’s handgun 

ran out of ammunition, officers subdued him. As they tried 

to handcuff Tamerlan, Dzhokhar returned to the SUV and 

sped towards the officers. They evaded the SUV. Tamerlan 

did not. Dzhokhar ran over Tamerlan and dragged him 

roughly 30 feet down the road. Tamerlan disentangled 

from the undercarriage when Dzhokhar rammed a police 
4 UNITED STATES v. TSARNAEV

Opinion of the Court

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 arrested 

him.

B

A federal grand jury indicted Dzhokhar for 30 crimes, 17 

of which were capital offenses. In preparation for jury selection, 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 personal connection to the bombing.

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 consumption. 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 
Cite as: 595 U. S. ____ (2022) 5

Opinion of the Court

media and other sources. Concerned that such a broad, “unfocused” question would “cause trouble” by producing “unmanageable 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 objected 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 first round of jury selection. After reviewing their answers 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 specific 

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.

After the District Court seated the jury, the case went to 

trial. Dzhokhar did not contest his guilt and the jury thus 

returned a guilty verdict on all counts. During the sentencing phase, the Government argued that Dzhokhar’s crimes 

warranted the death penalty. Dzhokhar’s mitigation theory centered on the idea that Tamerlan masterminded the 

bombing. According to Dzhokhar, he was not sufficiently 

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 
6 UNITED STATES v. TSARNAEV

Opinion of the Court

allegedly had committed years earlier. Specifically, FBI 

agents investigating 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 involvement. 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 ducttaped their hands, feet, and mouths. After taking the 

money, Tamerlan insisted on killing the three men. According to Todashev, after he disagreed, 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 instead 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 prosecution also disclosed that Dias Kadyrbayev, a friend of Dzhokhar’s facing federal obstruction charges in connection with 

the bombing, told the investigators that Dzhokhar knew 

about Tamerlan’s involvement in the murders. Meanwhile, 

Government 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 “infidels.” Id., at 639.

Before trial, Dzhokhar filed a motion to compel produc-
Cite as: 595 U. S. ____ (2022) 7

Opinion of the Court

tion of the evidence, which the court denied. The Government filed a motion in limine to exclude any reference to 

the Waltham murders, contending that the evidence was 

irrelevant, or at least so lacking in probative value and so 

likely to confuse the issues that the court should exclude it. 

The District 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 further 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 finished, the jury concluded that Dzhokhar warranted the death penalty for 6 of 

the 17 death-penalty-eligible crimes, despite Dzhokhar’s argument 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’] discretionary supervisory powers, not as a matter 

of constitutional 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 sufficiently probative 
8 UNITED STATES v. TSARNAEV

Opinion of the Court

of Tamerlan’s ability to influence Dzhokhar. Id., at 69–70. 

We granted certiorari, 592 U. S. ___ (2021).

II

The Government argues that the Court of Appeals improperly 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 “almost, as a matter of necessity, brought to the attention” of those informed citizens who are “best fitted” 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 “‘particularly 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 influenced by a host of factors impossible to capture fully in the record,” such as a 

“prospective juror’s inflection, sincerity, demeanor, candor, 

body language, 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 
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Opinion of the Court

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) 

(plurality 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 influence a juror.’” Ibid. (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 juryselection 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 recognized the significant pretrial publicity concerning the 

bombings, and reasonably concluded that the proposed 

media-content question was “unfocused,” risked producing 

“unmanageable data,” and would at best shed light on “preconceptions” 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
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Opinion of the Court

498. The court was concerned that a media-content question 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 

knowledge 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 discretion, as our precedents make clear. See Mu’Min, 500 U. S., 

at 427.

If any doubt remained, the rest of the jury-selection process 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 questionnaire asked prospective jurors what media sources they followed, 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 

opportunity 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 instructions on the sworn duty of each juror to decide the issues only on evidence presented in open court.’” Skilling, 

561 U. S., at 388, n. 21 (quoting Nebraska Press Assn. v. 

Stuart, 427 U. S. 539, 564 (1976)). The court reminded the 

prospective jurors that they “must be able to decide the issues 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, 
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Opinion of the Court

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 district courts presiding over high-profile 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 “supervisory 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 identified clear limits when 

lower courts have purported to invoke that authority. For 

example, supervisory rules cannot conflict with or circumvent a constitutional provision or federal statute. Thomas

v. Arn, 474 U. S. 140, 148 (1985). Nor can they conflict with 

or circumvent 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 circumvent or supplement legal standards set out in 

——————

1Some jurists have questioned this Court’s supervisory authority over 

lower courts. See, e.g., Western Pacific R. Corp. v. Western Pacific 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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decisions of this Court. United States v. Payner, 447 U. S. 

727, 733–737 (1980).

Payner exemplifies this last limit. There, a Federal District Court asserted supervisory power to suppress illegally 

seized evidence even when the seizure violated a third 

party’s Fourth Amendment rights, and the Court of Appeals 

affirmed 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 enforcing.” 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 

questions are required in all high-profile 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 
Cite as: 595 U. S. ____ (2022) 13

Opinion of the Court

specific lines of questioning, and thereby circumvent a wellestablished 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 Dzhokhar’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 comprehensive 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 admission of evidence at criminal trials.” Ibid.

That said, FDPA proceedings are not evidentiary free-foralls. The district court may exclude information under the 

FDPA “if its probative value is outweighed by the danger 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 murders. He argued that the evidence supported his mitigation 

defense that Tamerlan was the ringleader. The District 

Court acknowledged Dzhokhar’s rationale but excluded the 

evidence because it was “without any probative value” and 

“would be confusing to the jury.” App. 650. See 18 U. S. C. 

§3593(c).
14 UNITED STATES v. TSARNAEV

Opinion of the Court

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 Tamerlan allegedly committed years prior, though there was no 

allegation that Dzhokhar had any role in that crime. Nor 

was there any way to confirm or verify the relevant facts, 

since all of the parties involved were dead. As the District 

Court explained, “there simply [was] insufficient 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 finding 

that the evidence lacked probative value, would confuse 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) (slip op., at 17). Dzhokhar suggests that a district court violates the 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.

——————

2Some have argued that these cases and their progeny do not reflect 

the original meaning of the Eighth Amendment, whose prohibition “relates to the character of the punishment, and not the process by which it 

is imposed.” Gardner v. Florida, 430 U. S. 349, 371 (1977) (Rehnquist, 

J., dissenting); 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.
Cite as: 595 U. S. ____ (2022) 15

Opinion of the Court

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 presentation of mitigating evidence, either by statute or judicial 

instruction, or by limiting the inquiries to which it is relevant so severely that the evidence could never be part of the 

sentencing 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.” Saffle v. Parks, 494 U. S. 484, 493 

(1990); accord, 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 reconcile these objectives, “[w]e need only conclude that it is consistent with the Eighth Amendment for 

[the Federal Government] to channel the sentencer’s consideration of a defendant’s arguably mitigating evidence so 

as to limit the relevance 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 constitutionally 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 insufficient probative value to justify 

their admission,” they may enact reasonable rules governing whether specific pieces of evidence are admissible. 

Skipper v. South Carolina, 476 U. S. 1, 11, 15 (1986) (Powell, J., concurring in judgment) (quoting Lockett, 438 U. S., 

at 604, n. 12). Moreover, we have expressly held that “the 
16 UNITED STATES v. TSARNAEV

Opinion of the Court

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 traditional 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 

channels that evidence through an individualized balancing test that affords a capital defendant every reasonable 

opportunity 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 sentencer’s purview. Rather, §3593(c) preserves 

the traditional gatekeeping function of district court judges 

to consider and assess specific pieces of relevant evidence 

in light of its probative value and the risks it poses to the 

jury’s truth-seeking function. The court weighs all proffered evidence to determine 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 constitutionally relevant circumstances.” Graham, 506 U. S. at 

498–499 (THOMAS, J., concurring). It therefore does not offend 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. 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 reasonably explaining that “[t]here’s just no way of telling who played 

what role, if they played roles,” from the sparse and unreliable information before the court. App. 650. It was “as 
Cite as: 595 U. S. ____ (2022) 17

Opinion of the Court

plausible . . . that Todashev was the bad guy and Tamerlan 

was the minor actor.” Ibid. In other words, the evidence 

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 matter how Dzhokhar presented 

the evidence, its bare inclusion risked producing a confusing mini-trial where the only witnesses 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 apparently considered Todashev’s statement to the FBI 

agents reliable enough to justify its reference in a search 

warrant affidavit, 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 

8 (BREYER, J., dissenting) (contending that the warrant 

“strongly suggests” the District Court abused its discretion). We fail to see why. The District Court here did not 
18 UNITED STATES v. TSARNAEV

Opinion of the Court

sign the warrant or the affidavit. Whatever probable-cause 

assessment the FBI agent and the Magistrate Judge made, 

the District Court was free to evaluate the information independently 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 decision 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 5–16. While the dissent 

acknowledges that district courts enjoy “significant discretion” when making evidentiary decisions, post, at 5, it nevertheless argues that the death penalty context here requires us to scrutinize the District Court’s decision with 

“particular judicial care,” post, at 15.

In doing so, the dissent ignores our traditional standard 

for appellate review of evidentiary determinations.3 Deference is the “hallmark of [the] abuse-of-discretion review” 

applicable to such decisions. General Elec. Co. v. Joiner, 

——————

3None of the dissent’s cases, see post, at 16, 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 14, 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. Meanwhile, the language from Zant v. Stephens, 462 U. S. 862, 885 (1983), 

about “careful scrutiny” concerned our review of the jury’s “deliberative 

process” 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.), 

scrutinized 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”).
Cite as: 595 U. S. ____ (2022) 19

Opinion of the Court

522 U. S. 136, 143 (1997). A “reviewing court” applying that 

standard “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 abuseof-discretion standard applies.

Yet here, the dissent proposes to independently reevaluate the District Court’s decision to exclude the Waltham evidence under §3593(c). In particular, the dissent joins 

Dzhokhar in critiquing the District Court’s conclusion that 

the risk of confusing the jury outweighed the probative 

value of that evidence. See post, at 10–15. The dissent 

thinks it was the “District Court’s strongest reason” for excluding the evidence, post, at 10, but it discounts the District Court’s conclusion 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 hesitant to find a risk of confusion in this context than in others. Post, at 11. But the dissent identifies nothing in the 

text of the FDPA to support its position. Congress defined 

what considerations district courts must balance when 

making admissibility determinations under §3593(c), and it 

chose to define one using a term familiar in the law of evidence—“confusing 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 issues’”). Nothing suggests that Congress intended district courts to evaluate that concern differently 

under the FDPA.
20 UNITED STATES v. TSARNAEV

Opinion of the Court

Second, the dissent points out that district courts sometimes allow the Government to present evidence of a capital 

defendant’s past bad acts during sentencing proceedings, 

despite the risk of evidentiary minitrials. See post, at 13–

15. 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 participated 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 first have to show, without any surviving witnesses, 

what role Tamerlan actually played. Then, he would have 

to establish that he learned of the Waltham crimes before 

planning the bombings. Finally, he would have to explain 

how his knowledge of Tamerlan’s role in a nearly 2-year-old 

violent robbery affected his own role in the bombings. 

Whatever other courts might think about an inquiry into a 

defendant’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.
Cite as: 595 U. S. ____ (2022) 1

BARRETT, J., concurring

SUPREME COURT OF THE UNITED STATES

_________________

No. 20–443

_________________

UNITED STATES, PETITIONER v.

DZHOKHAR A. TSARNAEV

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE FIRST CIRCUIT

[March 4, 2022]

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. 

Because that rule (which required a district court to ask 

media-content questions on request in high-profile prosecutions) conflicts 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 first 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 understood 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 authority 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. Wabash R. Co., 370 U. S. 626 (1962) (a district court 

can dismiss a case sua sponte for failure to prosecute); 
2 UNITED STATES v. TSARNAEV

BARRETT, J., concurring

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 regulating 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 conflicts 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 procedures deemed desirable from 

the viewpoint of sound judicial 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 

——————

*In dissent, JUSTICE BREYER asserts that “our precedents clearly recognize the existence of” the courts of appeals’ supervisory power. Post,

at 17. But the cases cited by JUSTICE BREYER reflect 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 dismiss 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 file

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 

prosecutors of its jurisdiction,” not to regulate district courts. Id., at 505 

(emphasis 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.
Cite as: 595 U. S. ____ (2022) 3

BARRETT, J., concurring

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 justified this power either, it has an at least arguable basis: the Constitution’s establishment of this Court as 

“supreme,” as distinct from the “inferior Courts” that Congress has discretion to create. Art. III, §1. Much like the 

grant of “[t]he judicial Power” carries with it inherent authority over local procedure, this Court’s designation as “supreme” might carry with it some inherent authority to prescribe procedural rules for inferior federal courts. But see 

ante, at 11, n. 1. In the end, this argument might be unsupported by the Constitution’s structure and history. Still, 

the text of Article III makes it plausible.

Yet whatever the status of this Court’s supervisory authority, it is difficult, if not impossible, to find 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 distinct. 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 authority 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.
Cite as: 595 U. S. ____ (2022) 1

BREYER, J., dissenting

SUPREME COURT OF THE UNITED STATES

_________________

No. 20–443

_________________

UNITED STATES, PETITIONER v.

DZHOKHAR A. TSARNAEV

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF 

APPEALS FOR THE FIRST CIRCUIT

[March 4, 2022]

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 argued that Tamerlan was a highly violent man, 

that Tamerlan radicalized him, and that Dzhokhar participated in the bombings because of Tamerlan’s violent influence 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 District Court should have allowed Dzhokhar to introduce this 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 
2 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

the offense 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 

acknowledged that he participated in the Boston Marathon 

bombings. He conceded that he and his older brother Tamerlan planted bombs along the route of the Patriot’s Day 

Marathon and that the bombs killed or injured many innocent people. Given Dzhokhar’s concession, his trial focused 

almost exclusively on sentencing, in particular whether 

Dzhokhar should receive the death penalty. Dzhokhar argued in mitigation that his conduct was less serious than 

Tamerlan’s and that Tamerlan’s radicalizing influence 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 

defendant “to a life of crime” supported mitigation theory 

that defendant “may have desired to follow in the footsteps” 

of his older brother); Lockett, 438 U. S., at 608 (“defendant’s 

comparatively 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 influence 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 influence,” “[w]hether because of Tamerlan’s age, size, aggressiveness, domineering personality, 

privileged status in the family, traditional authority as the 

eldest brother, or other reasons”; (4) Tamerlan “planned, 

led, and directed the Marathon bombing”; and (5) Tamerlan 

“became radicalized first, and then encouraged his younger 

brother to follow him.” App. 614, 616 (boldface omitted). 
Cite as: 595 U. S. ____ (2022) 3

BREYER, J., dissenting

The District Court also allowed Dzhokhar to introduce certain evidence 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 

Tamerlan’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 interviews 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 

committed 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 dealers’ 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.

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 affidavit attached to the search warrant request stated that Todashev had
4 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

“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 witnesses to the crime, and then Todashev and 

Tamerlan bound the victims, who were ultimately murdered.” Id., at 998.

Based on this and other less significant evidence, the FBI 

agent asserted that there was “probable cause to believe 

that Todashev and Tamerlan planned and carried out” the 

Waltham 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 Waltham 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 participation 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 evidence 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 

Tamerlan had become radicalized before Dzhokhar and encouraged Dzhokhar to follow his example. Id., at 616. 

Three found that Tamerlan planned, led, and directed the 

bombings. Id., at 614. Three also found that Dzhokhar 

acted under Tamerlan’s influence, that he was particularly 

susceptible to Tamerlan’s influence, and that he would not 

have committed the bombings but for Tamerlan. Ibid. The 
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BREYER, J., dissenting

jury nonetheless unanimously recommended the death penalty for Dzhokhar in respect to those counts involving the 

bomb that he himself—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 7. First, the trial court had not adequately questioned 

potential jury members about the content of the pretrial 

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 Appeals) at least as to the second reason.

II

A

The Federal Death Penalty Act sets forth the legal standards governing the admissibility of mitigating evidence during 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 proceedings, “information may be presented as to any matter 

relevant to the sentence, including any mitigating or aggravating factor.” §3593(c). And that is so whether that “information” is or is not admissible “under the rules governing admission of evidence at criminal trials.” Ibid. The 

statute also provides that a trial court “may” exclude evidence “if its probative value is outweighed by the danger of 

creating unfair prejudice, confusing the issues, or misleading the jury.” Ibid.

As the majority points out, district courts have significant 

discretion in deciding how to apply and weigh the statute’s 

factors. Ante, at 13–14. But “abuse-of-discretion review is 

not toothless; and it is entirely proper for a reviewing court 
6 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

to find an abuse of discretion when important factors . . . 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] adequately considered the factors relevant” to the question); 

Highmark Inc. v. Allcare Health Management System, Inc., 

572 U. S. 559, 564, n. 2 (2014) (“The abuse-of-discretion 

standard does not preclude an appellate court’s correction 

of a district court’s . . . clearly erroneous assessment of the 

evidence” (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 observed”); 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] insufficient 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 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 
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BREYER, J., dissenting

District Court gave: (1) no probative value; (2) insufficient 

evidence to corroborate Tamerlan’s role in the murders; 

(3) waste of time; and (4) jury confusion. Reading the record in light of these factors, I believe that the Court of Appeals was correct that the District Court abused its discretion 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 

(“Relevant mitigating evidence is evidence which tends logically to prove or disprove some fact or circumstance which 

a fact-finder could reasonably deem to have mitigating 

value” (internal quotation marks omitted)). And it possessed probative 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 evidence tended to show that Tamerlan committed these murders 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 behind the ideologically motivated bombings a year and a half later.

2. Corroboration/Reliability

The Waltham evidence was corroborated and sufficiently 
8 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

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 computer for “3 men killed in Waltham,” “men 

kill in Waltham,” and “tamerlan tsarnaev.” App. 590. Tamerlan’s wife also confirmed 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 sufficiently reliable 

for the Government to conclude (via FBI affidavit) 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 17–18. But the fact that both the Government and a federal judge found the evidence sufficiently 

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 

mitigating 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” (internal quotation marks and brackets omitted; 

emphasis added)).
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BREYER, J., dissenting

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 during 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 turkey 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 nature than any of these incidents. Cf. Skipper v. 

South Carolina, 476 U. S. 1, 8 (1986) (reversible error 

where excluded mitigating evidence had “greater weight” 

than evidence supporting same mitigating factors).

Similarly, the evidence introduced to show Tamerlan’s influence 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 position of authority and superiority vis-à-vis Dzhokhar; (4) 

that Tamerlan sent Dzhokhar articles containing extremist 

propaganda; and (5) that Tamerlan traveled to Russia in 

2012 as part of an unsuccessful effort to wage “jihad.” But 

the Waltham evidence showed (if the jury believed 

Todashev’s account) that Tamerlan had previously exerted 

such influence over Todashev as to make him an unwilling 

accomplice to a triple murder. This is much stronger evidence of Tamerlan’s capacity to influence than any evidence 

that the jury heard.
10 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

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 Tamerlan, 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 [Dzhokhar’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 because Dzhokhar’s mitigation evidence merely 

showed that Tamerlan was “loud,” “bossy,” and “sometimes 

lost his temper.” 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 instruction reversible error where “repeatedly emphasized and argued” 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 

prosecution 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-
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BREYER, J., dissenting

cluding the Waltham evidence, and the majority’s best argument 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 probative 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 discretion by excluding the evidence.

First, death penalty proceedings are special. Unlike evidentiary 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 capital 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 consider and give effect to a capital defendant’s mitigating evidence” (internal quotation marks omitted)). So, although 

the Federal Death Penalty Act incorporates some of the features that ordinarily guide a trial judge’s discretionary decision to admit or exclude evidence, see Fed. Rule Evid. 403, 

it also provides a special admissibility standard unique to 

the capital sentencing context. Specifically, the statute 

says that “information may be presented as to any matter 

relevant to the sentence, including any mitigating or aggravating factor,” regardless of whether that information 

would be admissible under normal evidentiary rules. 

§3593(c) (emphasis added). The statute thus tips the balance in favor of admitting mitigating evidence, even if ad-
12 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

mission means increasing the length of a proceeding by inviting some “minitrials” over subsidiary issues. Cf. McKoy

v. North Carolina, 494 U. S. 433, 442 (1990) (“The Constitution requires States to allow consideration of mitigating 

evidence in capital cases”); see also Smith v. Texas, 543 

U. S. 37, 44 (2004) (per curiam). This weighted scale makes 

sense in the context of capital proceedings, in a way it would 

not make sense in run-of-the-mill evidentiary disputes, 

“[g]iven that the imposition 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 different 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 specific case.” Woodson v. North Carolina, 428 

U. S. 280, 305 (1976) (plurality opinion). And a jury’s decision to impose the death penalty 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); 

Geders v. United States, 425 U. S. 80, 86–87 (1976) (“Within 

limits, the judge . . . may refuse to allow cumulative, repetitive, or irrelevant testimony, and may control the scope of 

examination of witnesses” (citations omitted)). In the context of capital sentencing, then, concerns about juror “waste 

of time” or the risk of “confusion” are less justifiable bases 

on which to exclude an entire category of evidence that may 

have significant mitigating value.
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BREYER, J., dissenting

Second, and perhaps of greater importance, a sampling of 

other death penalty proceedings indicates that the prosecution often introduces evidence of a defendant’s prior criminal behavior in support of the death penalty, including evidence 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” deathpenalty-related factor such as a defendant’s risk of future 

dangerousness. If courts admit evidence of past criminal 

behavior, unrelated to the crime at issue, to show aggravating circumstances, why should they not do the same to show 

mitigating 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. 

Gabrion, 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 defendant’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 admitted 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 admitted evidence that “defendant has committed an array of other criminal acts, 
14 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

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 

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 20. To the contrary, 

just as the Government introduces evidence of a defendant’s prior unproved bad conduct to show a defendant’s dangerousness, 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 

Tamerlan’s character instead of Dzhokhar’s did not render 

the evidence beyond the jury’s ability to comprehend. The 

District 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 aggravation. See Payne v. Tennessee, 501 U. S. 808, 823 

(1991) (rejecting reasoning that victim impact evidence 

should be excluded 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 preclude a defendant from introducing similar evidence in mitigation? 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 
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BREYER, J., dissenting

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 vacated 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 reflected close attention to 

the relationship between the brothers: The jury did not recommend the death penalty for the charges related to the 

actions Dzhokhar took together with Tamerlan, and only 

recommended death for the charges related to the actions 

Dzhokhar took alone. The Waltham evidence supported 

Dzhokhar’s theory that Tamerlan’s violent and radicalizing 

influence induced all of the actions Dzhokhar took in connection with the Boston Marathon bombings. This evidence 

may have led some jurors to conclude that Tamerlan’s influence was so pervasive that Dzhokhar did not deserve to 

die for any of the actions he took in connection with the 

bombings, 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 

proceeding. 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 
16 UNITED STATES v. TSARNAEV

BREYER, J., dissenting

“[s]pecial hearing to determine whether a sentence of death 

is justified” (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”); Gregg, 428 U. S., at 187 (joint opinion) (“When a defendant’s life 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 difficult for judges, as it 

would be difficult for anyone, not to apply legal requirements punctiliously when the consequences of failing to do 

so may well be death”). That same care applies on abuseof-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 Waltham 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 promulgate supervisory rules. See ante, at 11. Like the Court (and 

JUSTICE BARRETT), I recognize that the Government “does 

not challenge the general existence of the Court of Appeals’ 
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BREYER, J., dissenting

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 supervisory 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 limits, formulate procedural rules not specifically 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 this power “is limited in scope.” Ortega-Rodriguez

v. United States, 507 U. S. 234, 244 (1993). And I do not 

find that surprising. A degree of authority for the courts of 

appeals, closer to the fray, to issue at least some supervisory rules facilitates the flexibility needed in our geographically dispersed multicircuit system.

* * *

For these reasons, with respect, I dissent.