In the 1991 case of Derrick Morgan v. Illinois, the United States Supreme Court addressed whether a defendant in a capital murder trial had the right to exclude jurors who would automatically vote for death penalty upon conviction. The court ruled that such jurors could indeed be excluded from serving on juries in capital cases if they made it clear that their views about capital punishment would prevent or substantially impair them from making an impartial decision as required by their oath as jurors. This was based on principles of fairness and impartiality, ensuring that defendants receive a fair trial by an unbiased jury. The ruling clarified previous decisions regarding juror bias and expanded protections for defendants facing potential death sentences.

In the case of Derrick Morgan v. Illinois, the dissenting opinion argued that the majority's decision to allow for "death-qualified" juries -- those willing to impose capital punishment -- was fundamentally unfair and biased towards conviction. The dissenters believed this practice violated a defendant's right to an impartial jury as guaranteed by the Sixth Amendment. They pointed out that such juries are more likely to convict than non-death-qualified ones, creating an inherent bias against defendants in capital cases. Furthermore, they asserted that excluding potential jurors who oppose death penalty from serving on a jury undermines diversity and does not reflect community values accurately. Therefore, they disagreed with allowing states broad discretion in determining juror qualifications based on their willingness or ability to impose death sentences.