Hello and thank you for your question.
It depends if the case is a criminal or civil case. If the case is a civil case, then a party may file a motion to set aside a judgment for fraud on the court under Rule 60(d)(3). Judicial misconduct can be grounds for a motion for recusal, setting aside a judgment, or grounds for appeal.
In the context of a criminal case, the concept of judicial bias, misconduct or impropriety is addressed more in terms of the rights to a fair trial and due process, and can be the basis of a motion for recusal of the judge, for post-conviction relief or for a new trial
, or grounds for appeal.
The case of Litkey v. United States, 510 U.S. 540 (1993) addresses the level of judicial bias and prejudice that must be shown for relief.
In Liteky, the Supreme Court stated: First, judicial rulings alone almost never constitute a valid basis for a bias or partiality motion. See United States
Corp., 384 U. S., at 583. In and of themselves (i. e.,
apart from surrounding comments or accompanying opinion), they cannot possibly show reliance upon an extrajudicial source; and can only in the rarest circumstances evidence the degree of favoritism or antagonism required (as discussed below) when no extrajudicial source is involved. Almost invariably, they are proper grounds for appeal, not for recusal. Second, opinions formed by the judge on the basis of facts introduced or events occurring in the course of the current proceedings, or of prior proceedings, do not constitute a basis for a bias or partiality motion unless they display a deep-seated favoritism or antagonism that would make fair judgment impossible. Thus, judicial remarks during the course of a trial that are critical or disapproving of, or even hostile to, counsel, the parties, or their cases, ordinarily do not support a bias or partiality challenge. They may
do so if they reveal an opinion that derives from an extrajudicial source; and they will
do so if they reveal such a high degree of favoritism or antagonism as to make fair judgment impossible. . . . Not
establishing bias or partiality, however, are expressions of impatience, dissatisfaction, annoyance, and even anger, that are within the bounds of what imperfect men and women, even after having been confirmed as federal judges, sometimes display. A judge's ordinary efforts at courtroom administration-even a stern and short tempered judge's ordinary efforts at courtroom administration-remain immune. (pp. 555-556)
The full text of Litkey may be found here http://supreme.justia.com/cases/federal/us/510/540/case.html
Please feel free to ask any follow-up questions.