In United States v. McDonald, 55 M.J. 173 (C.A.A.F. 2001), the CAAF has held that the Sixth Amendment confrontation right does not apply at sentencing, but that the Fifth Amendment does.
Here is an interesting case from the Supreme Court of Arkansas, Vankirk v. State, which applies the confrontation right to a jury (members) case. Here are Prof. Friedman’s thoughts:
I think this case is a good illustration of the issue of confrontation rights in sentencing. Suppose the girl had testified live at the sentencing proceeding, but at the conclusion of direct, as defense counsel was rising to cross-examine, the judge said, "You are excused. We have no need for cross-examination, so I will not allow it." I think that would plainly be unconstitutional – if not under the Confrontation Clause, . . . then under the Due Process Clause. So should the result be any different when the witness testifies just outside the courtroom on videotape and the tape is played at the proceeding? When I refer to the speaker as a witness and say that she is testifying, I am drawing on one of the essential points of Crawford: Simply because a person (such as Sylvia Crawford) speaks out of court does not mean that she is not testifying, and indeed the central focus of the Confrontation Clause is to require that testimony be given in court, under prescribed procedures[.]
So perhaps the U.S. Supreme Court should go the full route of holding that the Confrontation Clause applies with full force to all sentencing proceedings. It may be reluctant to do so, however. One possibility would be to hold that the Confrontation Clause itself does not apply to most sentencing proceedings (i.e., that it does not apply beyond the scope of Apprendi), but that, not withstanding Williams v. New York, 337 U.S. 241 (1949), it does provide some right of confrontation, perhaps more easily overcome than the Sixth Amendment right.
h/t Professor Friedman.