A jury’s question, brushed aside as insignificant by the chief justice of the United States, might have made a life-or-death difference, according to a study that challenged the chief justice’s assumptions with mock jurors. A Cornell University law professor, Stephen Garvey, undertook a study of a jury instruction in the penalty phase of the 1993 trial of Virginia cop-killer Lonnie Weeks Jr., who faces execution on March 16.

Chief Justice William H. Rehnquist wrote in a Jan. 19 opinion denying Weeks’ petition for habeas corpus that there was only a “slight possibility” that jurors had been confused by the trial judge’s instructions.