The so-called undue prejudice rule empowers a trial judge to exclude relevant and probative evidence in order to reduce the risk of prejudice and avert other risks and harms.

United States v. Gutman, 725 F.2d 417, 420 (7th Cir. 1984) ( "Although insanity as such is no longer a ground for disqualifying a witness, see Fed.R.Evid. 601, a district judge has the power, and in an appropriate case the duty, to hold a hearing to determine whether a witness should not be allowed to...A trial court has the authority -- under some circumstances -- to disqualify a person with a mental infirmity or disorder from serving as a witness.

United States v. Wheeler, 540 F.3d 683, 692 (7th Cir. 2008) (upholding trial court's admission of the Fortran evidence because it satisfied the third prong of Rule 404 (b) analysis where "the government adduced sufficient evidence that a jury could reasonably find that [accused] was...Evidence of another crime, wrong, or act is admissible if there is sufficient evidence to support a finding by a reasonable juror that the other crime, wrong, or act occurred. Clear and convincing evidence is unnecessary; "sufficient" means only that there must be enough evidence to make the other crime, wrong, or act relevant.

United States v. Jackson, 335 F.3d 170, 178-179 (2d Cir. 2003) (upholding trial court's exclusion of another person's plea allocution under Rule 804(b)(3) because "[defendant] cannot satisfy Rule 804(b)(3) considering that....A statement falls within the federal hearsay exception for statements against interest only if the statement at the time of its making so far contrary to the declarant's pecuniary or proprietary interest, or so far tended to subject the declarant to civil or criminal liability, or to render invalid a claim by the declarant against another, that a reasonable person in the declarant's position would not have made the statement unless believing it to be true.