The United States Supreme Court held in a 6 - 3 decision, that a criminal defendant suffered no confrontation clause violation when excluded from the in-chambers competency hearing of two minor witnesses.
Kentucky v. Stincer, 107 S. Ct. 2658 (1987).
David T. Fisfis,
Sixth Amendment - Confrontation Clause,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol26/iss4/12