How can the court and public guarantee disregard by jurors when they're instructed to do so? I doubt that a verbal instruction suffices, when judges themselves can be biased. What forestalls or thwarts such potential subconscious regard or bias?
Source: Richard A. Posner, How Judges Think (2008), p. 9 Top.
Criminal defendants are at a disadvantage if a judge's or prosecutor's missteps can be forgiven by the judge's telling the jury to disregard them, for the bell cannot be unrung; the jurors cannot exclude what they should not have heard from their consideration of the defendant's guilt.