The right at stake is structural: nobody should be the judge of the case for their own removal. Illinois codifies that in 725 ILCS 5/114-5(d), which permits a criminal defendant to move for substitution for cause.
The threshold question controls everything
A motion that meets the statutory threshold is directed to be heard by a different judge. The strongest litigation position is therefore usually not that the alleged prejudice is true, but the narrower one: that the law says someone else decides.
The documented example
A verified renewed motion for substitution for cause was file-stamped July 23, 2026 in Lake County No. 23 CF 1146. On the same date, the clerk file-stamped a notice setting the matter for August 6 in the courtroom of the judge named in the motion. See the two stamps.