The confrontation clause of the U.S. Constitution requires that testimonial statements of witnesses absent from trial can be admitted only where the declarant is unavailable, and only where the defendant has had a prior opportunity to cross-examine. Where testimonial statements are at issue, the only indicators of reliability sufficient to satisfy constitutional demands is the opportunity for cross-examination.
The Sixth Amendment to the U.S. Constitution provides:
"In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation, to be confronted with the witnesses against him, to have compulsory process for obtaining witnesses in his favor, and to have the assistance of counsel for his defense."
