Wainwright v. Witt
In Wainwright v. Witt, 469 U.S. 412 (1985), the U.S. Supreme Court limited the death penalty precedent of Witherspoon v. Illinois to "the context of its facts." Id. at 418. The Court noted that in Witherspoon the trial court had excused half the venire -- every juror with conscientious objections to capital punishments. 469 U.S. at 416. Furthermore, the state sentencing scheme under which Witherspoon's sentence was imposed permitted the jury "unlimited discretion in choice of sentence." Id. at 421. When a juror is given unlimited discretion, the Court explained, all he or she must do to follow instructions is consider the death penalty, even if in the end he or she would not be able to impose it. Ibid. Rejecting the strict standard found in Witherspoon's footnote 21, the Court recognized that the diminished discretion now given to capital jurors and the State's interest in administering its capital punishment scheme called for a different standard. The Court relied on Adams v. Texas, 448 U.S. 38, 45 (1980), which provided the following standard: "Whether the juror's views would prevent or substantially impair the performance of his duties as a juror in accordance with his instructions and his oath." Witt, 469 U.S. at 424 (internal quotation marks omitted).
The Court in Witt instructed that, in applying this standard, reviewing courts are to accord deference to the trial court. Deference is owed regardless of whether the trial court engages in explicit analysis regarding substantial impairment; even the granting of a motion to excuse for cause constitutes an implicit finding of bias. Id. at 430. The judgment as to "whether a veniremen is biased . . . is based upon determinations of demeanor and credibility that are peculiarly within a trial judge's province. Such determinations [are] entitled to deference even on direct review; the respect paid such findings in a habeas proceeding certainly should be no less." Id. at 428 (internal quotation marks, footnote, and brackets omitted). And the finding may be upheld even in the absence of clear statements from the juror that he or she is impaired because "many veniremen simply cannot be asked enough questions to reach the point where their bias has been made 'unmistakably clear'; these veniremen may not know how they will react when faced with imposing the death sentence, or may be unable to articulate, or may wish to hide their true feelings." Id. at 424-425. Thus, when there is ambiguity in the prospective juror's statements, "the trial court, aided as it undoubtedly [is] by its assessment of [the venireman's] demeanor, [is] entitled to resolve it in favor of the State." Id. at 434.
Subsequent decisions have refined this standard further.