What is the role of a federal trial judge in questioning a witness?

The trial judge is charged with the responsibility of conducting the trial as impartially and fairly as possible. As noted by this court in Smith v. United States, 305 F.2d 197, 205 cert. denied, 371 U.S. 890, 83 S.Ct. 190, 9 L.Ed.2d 124 (1962), "a federal trial judge ... is more than a moderator or umpire. He has the responsibility to preside in such a way as to promote a fair and expeditious development of the facts unencumbered by irrelevancies." Thus, the trial judge may question a witness if he deems it necessary to clarify a matter or to more fully develop the facts for the benefit of the jury.

While the trial judge has a broad discretion with respect to his interrogation of witnesses, he must always be sensitive to his role as judge and the fact that in the eyes of the jury he "occupies a position of preeminence and special persuasiveness" and accordingly, "be assiduous in performing his function as governor of the trial dispassionately, fairly and impartially". United States v. Cassiagnol, 420 F.2d 868, 879 (4 Cir. 1970), cert. denied. 397 U.S. 1044, 90 S.Ct. 1364, 25 L.Ed.2d 654, citing Pollard v. Fennell, 400 F.2d 421, 424 (4 Cir. 1968).