## Facts

- Dzhokhar Tsarnaev and his brother Tamerlan planted and detonated two pressure-cooker bombs at the 2013 Boston Marathon, killing three people and injuring hundreds.
- During their flight from law enforcement, the brothers killed a campus police officer, carjacked a graduate student, and engaged police in a street confrontation in which Dzhokhar ran over and killed Tamerlan.
- Dzhokhar was captured hiding in a covered boat in a nearby backyard.
- A federal grand jury indicted him on 30 counts, including 17 capital offenses.
- Before trial, extensive publicity raised concerns about juror bias; the parties proposed a 100-question juror questionnaire.
- The district court declined to require prospective jurors to list all case-related “facts” learned from media sources, but used a detailed questionnaire and conducted weeks of individual voir dire with follow-up questioning.
- A jury convicted Tsarnaev on all counts and returned death recommendations on capital counts; the district court imposed death sentences.
- The First Circuit vacated the death sentences, relying on supervisory power to fault voir dire and holding that the district court improperly excluded certain mitigation evidence concerning Tamerlan’s alleged involvement in unrelated murders.

## Issues

1. Whether an appellate court may vacate federal death sentences by using supervisory power to require a specific voir dire question compelling jurors to enumerate information learned from pretrial publicity.
2. Whether the district court abused its discretion in excluding proposed mitigation evidence alleging Tamerlan’s participation in the “Waltham murders,” offered to support a theory that Tamerlan dominated and directed Dzhokhar.

## Decision

- The Supreme Court reversed the First Circuit and reinstated Tsarnaev’s death sentences.
- The Court held that the district court did not abuse its discretion in conducting voir dire without requiring jurors to provide a detailed accounting of media-derived facts.
- The Court held that excluding the Waltham-murders evidence was within the district court’s discretion because the proffer was weak and likely to confuse the jury and prolong proceedings.
- Justice Barrett concurred, agreeing the First Circuit misused supervisory power.
- Justice Breyer dissented (joined by Justices Sotomayor and Kagan, except one part), concluding the voir dire and mitigation rulings warranted a new penalty phase.

## Legal Principles

- Trial courts have broad discretion over voir dire; the constitutional guarantee is an impartial jury, not jurors wholly unaware of the case.
- Appellate reversal of voir dire management requires a showing that the trial court’s choices were manifestly unreasonable under an abuse-of-discretion standard.
- Federal appellate supervisory power cannot be used to impose rigid, preferred voir dire practices inconsistent with deferential review of trial management.
- In capital sentencing, defendants may present mitigating evidence, but courts may exclude mitigation whose limited probative value is substantially outweighed by risks of confusion, delay, or distraction, consistent with evidentiary balancing principles and 18 U.S.C. § 3593(c).

## Conclusion

The Court reinstated Tsarnaev’s federal death sentences, holding that the district court acted within its discretion in managing voir dire amid heavy publicity and in excluding tenuous, potentially confusing mitigation evidence about an unadjudicated triple homicide.


United States v. Tsarnaev, 595 U.S. 302 (2022)