## Facts

- Terrance Williams was convicted in Pennsylvania for the 1984 robbery and murder of Amos Norwood and was sentenced to death.
- As Philadelphia District Attorney, Ronald D. Castille personally approved the prosecutor’s request to seek the death penalty in Williams’s case and led the office that prosecuted the case.
- After Williams’s conviction and sentence were repeatedly upheld, Williams filed a successive petition under Pennsylvania’s Post-Conviction Relief Act alleging prosecutorial misconduct, including suppression of exculpatory evidence and use of false testimony.
- A trial court granted post-conviction relief and stayed the execution based on findings of prosecutorial misconduct.
- On the Commonwealth’s appeal, Castille—by then Chief Justice of the Pennsylvania Supreme Court—refused to recuse despite Williams’s motion citing Castille’s prior approval of the capital charging decision and related public statements about defendants he had “sent” to death row.
- Castille denied the recusal motion himself, did not refer the question to the full court, and participated in a unanimous decision vacating the post-conviction relief and reinstating the death sentence.

## Issues

1. Whether the Due Process Clause is violated when a state supreme court justice participates in a case after having had significant, personal involvement as a prosecutor in a critical decision in the same case, including approval to seek the death penalty.
2. Whether due process is violated by the participation of a potentially biased justice on a multi-member court even if the justice’s vote is not outcome-determinative.

## Decision

- The Supreme Court vacated the Pennsylvania Supreme Court’s judgment and remanded for further proceedings without Castille’s participation.
- The Court held that due process is violated when a judge had significant, personal involvement as a prosecutor in a critical decision in the defendant’s case and later sits in judgment of the same case.
- Castille’s denial of the recusal motion and subsequent participation created an impermissible risk of actual bias and violated the Fourteenth Amendment’s Due Process Clause.
- The failure to recuse under these circumstances was structural error and was not subject to harmless-error review, regardless of whether Castille’s vote was decisive.

## Legal Principles

- Due process is denied when the probability of actual bias is too high to be constitutionally tolerable; proof of actual bias is not required.
- A judge must recuse when the judge previously had significant, personal involvement as a prosecutor in a critical decision regarding the same defendant’s case.
- Approval of the decision to seek the death penalty is a critical prosecutorial decision for due process recusal analysis.
- The participation of a disqualified judge on a multi-member tribunal taints the proceeding even if the judge’s vote does not change the outcome.
- An unconstitutional failure to recuse in these circumstances is structural error requiring automatic reversal rather than harmless-error review.

## Conclusion

The Court held that due process required Chief Justice Castille’s recusal because he personally approved the decision to seek the death penalty in Williams’s case as district attorney; his later judicial participation was structural constitutional error, requiring vacatur and remand for reconsideration by an unbiased court.


Williams v. Pennsylvania, 579 U.S. 1 (2016)