Court noted: The primary object of the [Confrontation Clause] was to prevent depositions or ex parte affidavits ... being used against the prisoner in lieu of a personal examination and cross-examination of the witness, in which the accused has an opportunity, not only of testing the recollection and sifting the conscience of the witness, but of compelling him to stand face to face with the jury in order that they may look at him, and judge by his demeanor upon the stand and the manner in which he gives his testimony whether he is worthy of belief. [Mattox v. United States, 156 U.S. 237, 242-43, 15 S.Ct 989, 94 L.Ed.2d 40 (1987) (determining that Confrontation Clause does not compel pre-trial discovery); Bourjaily v. United States, 483 U.S. 171, 107 S.Ct. 2775, 97 L.Ed.2d 144 (1987) (<HOLDING>); United States v. Inadi, 475 U.S. 387, 106
recognizing that statements admissible under an exception to the hearsay rule may be inadmissible when tested against the confrontation clause  because confrontation clause analysis differs from hearsay rule analysis holding that doctrine does not violate right of confrontation holding that statements within a firmly rooted hearsay exception do not violate the confrontation clause holding that hearsay objection does not preserve a confrontation clause challenge holding coconspirator hearsay exception does not violate confrontation clause