The right of a defendant in a criminal trial to call witnesses in his own defense has been called "an essential attribute of our adversarial system, fundamental to a fair trial, and basic to due process of law." Littlejohn v. United States, 705 A.2d 1077, 1082 (D.C. 1997). Nevertheless, that right is not absolute; in particular, it may be overcome when it "collides with the Fifth Amendment right of a trial witness" to be free from compulsory self-incrimination. Carter v. United States, 684 A.2d 331, 335 (D.C. 1996) (en banc). "In the crunch, when all else fails, the Fifth Amendment privilege of the witness prevails over the defendant's right to compel him to testify." Wilson v. United States, 558 A.2d 1135, 1140 (D.C. 1989). The witness' privilege, however, applies only "to those specific questions to which his answers would incriminate him." Id. at 1141. Therefore, as a general rule, when a witness' invocation of his Fifth Amendment privilege conflicts with a defendant's right to compulsory process under the Sixth Amendment, the trial court must "rule on the claim of privilege one question at a time." Harris v. United States, 614 A.2d 1277, 1282 (D.C. 1992); accord, e.g., Wilson, 558 A.2d at 1140. "A blanket privilege may be granted to the witness only when it is evident to the court that anything less will not adequately protect him." Littlejohn, 705 A.2d at 1083.