By: Tigran W. EldredThe U.S. Supreme Court’s recent decision in Williams v. Pennsylvania, handed down during the turmoil in the presidential campaign over the heated rhetoric on judicial impartiality, adds to the Supreme Court’s growing jurisprudence on the due process requirements for judicial disqualification. The issue in the case—whether a justice on the Pennsylvania Supreme Court could properly adjudicate a death penalty case when he had previously been the prosecutor who authorized capital charges against the defendant—set the stage for a ruling that could have provided broad guidance on the due process parameters for judicial disqualification, especially in criminal cases. Yet the Court’s holding may end up having only limited impact. As others have already started to note, the test announced by the Court—“that under the Due Process Clause there is an impermissible risk of actual bias when a judge earlier had significant, personal involvement as a prosecutor in a crucial decision regarding the defendant’s case”—will be hard to prove and adds little additional guidance to what is already available under existing ethical standards for judicial recusal in most states. In addition, my guess is that there are few cases in which a prosecutor-turned-judge will be asked to rule on a case in which he or she was previously involved, so this test is likely to directly apply to only a narrow band of future situations.