In Wainwright v. Witt, 469 U.S. 412 (1985) the Court held that the proper standard by which a prospective juror may be challenged and excluded for cause is "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.' " The Court thereby clarified its decision in Witherspoon v. Illinois, dispensing with Witherspoon v. Illinois reference to "automatic" decision making and the need to prove a juror's bias with "unmistakable clarity" (Witt, at 424). The Court reasoned, "is because determinations of juror views cannot be reduced to question-and-answer sessions which obtain results in the manner of a catechism" (id.). However, the Court did not explicitly overrule Witherspoon v. Illinois, noting that the standard found therein was dicta embodied in footnotes rather than in the main body of text (id., at 422). Wainwright reaffirmed the Adams v. Texas, 448 U.S. 38 (1980), standard for determining when a veniremember may be excluded for cause due to his or her views on capital punishment, holding that the critical inquiry is "whether a juror's views would prevent or substantially impair the performance of his duties as a juror in accordance with his instructions and his oath." Id. (discussing Wainwright, 469 U.S. at 424).