What is the current state of the law on juror bias?

The Sixth Amendment guarantees a fair trial by an impartial jury. Tinsley v. Borg, 895 F.2d 520, 523 (9th Cir.1990), cert. denied, 498 U.S. 1091 (1991). If even a single juror is "unduly biased or prejudiced" the defendant has been denied his right to an impartial jury. Id. at 523-24. The remedy for alleged juror bias is a post-trial hearing in which the defendant has a chance to prove bias. Id. at 524.

In a collateral review of such a post-trial hearing, we must give the state court's factual findings a presumption of correctness, unless of course the determination is "not fairly supported" by the state court record. 28 U.S.C. 2254(d). This presumption applies to the factual findings of the trial court as well as to the findings of the appellate court. Rushen v. Spain, 464 U.S. 114, 120 (1983) (per curiam). The question of whether an individual juror was biased is not a mixed question of law and fact, it is "plainly one of historical fact." Patton v. Yount, 467 U.S. 1025, 1036 (1984). Because this determination is "essentially one of credibility, and therefore largely one of demeanor ... the trial court's resolution of such questions is entitled ... to 'special deference. ' " Id. at 1038 (emphasis added).