The Confrontation Clause guarantees an essential element of the adversarial trial process. The clause envisions a trial where the accused sees and hears prosecution witnesses testify in person, in open court, in his presence, and subject to cross-examination. But that basic starting point still leaves difficult questions about the scope and limits of these rights. Is face-to-face confrontation always required? Or, given modern technology, can we substitute a rough equivalent—a video camera connection for example—where necessary to obtain a witness’s testimony? What limits can a court place on cross-examination? And when does the clause allow prosecutors to use hearsay from an out-of court declarant who cannot be cross-examined?

The text of the clause suggests some basic limits, and some ambiguity. The verb “confront” has always been understood to mean more than just a right to see and listen. It includes the right to challenge the witness and to test his credibility through cross-examination. The clause applies to “witnesses against” the accused, but a satisfactory definition of that term has proved elusive. Clearly it includes someone called by the prosecution to testify at trial. Whether it includes, as mentioned above, a hearsay declarant—a person whose out-of-court statement is offered in evidence against the accused, though that person never appears in court to testify (and thus is not subject to cross-examination)—is a question that continues to challenge the courts.

There is no record of any debate over the Confrontation Clause in the First Congress. Nevertheless, history offers some guidance to understanding the purpose of the clause. By the time the American Constitution was drafted, trials featuring live testimony in open court were typical in English and American criminal courts, though few defendants were represented by counsel, and the practice of cross-examination was in its infancy. The Framers likely were familiar with the very different procedure in a series of early seventeenth-century “State Trials,” where British prosecutors or examining magistrates obtained affidavits or depositions in private, then presented them as evidence in trials for treason against the crown. Defendants futilely demanded to have their accusers brought before them face to face. The American colonists themselves faced similar abuses in the 1760s, when Parliament allowed the colonial vice-admiralty courts to try certain offenses using a “civil law” model of trial based on written interrogatories instead of live testimony. Both George Mason and John Adams publicly condemned that practice. As the Supreme Court declared in its first major Confrontation Clause opinion, “The primary object of [the clause] was to prevent depositions or ex parte affidavits, such as were sometimes admitted in civil cases, being used against the prisoner in lieu of a personal examination and cross-examination of the witness.” Mattox v. United States (1895).

Under the current state of the law, in most circumstances, basic confrontation rights are well settled. The clause gives a defendant the right to be present in the courtroom when prosecution witnesses testify. Kentucky v. Stincer (1987). The clause guarantees an “adequate opportunity” for “effective” cross-examination. Pointer v. Texas (1965).

Applying these basic principles has proved especially difficult in two circumstances, (1) confrontation and hearsay, and (2) child witnesses and face-to-face confrontation.

When a witness at trial merely repeats “hear-say,” a statement made out of court by someone else (the declarant), and when that declarant does not testify at trial, the defendant cannot “confront” or cross-examine him. Yet recognizing that British and American courts admitted some forms of hearsay both before and after 1791, the Supreme Court has not gone so far as to hold that all incriminating hearsay is inadmissible when the declarant cannot be confronted. After a series of cases that had sought to establish “exceptions” to the confrontation right based on the “reliability” of some forms of hearsay, the Court changed its course in Crawford v. Washington (2004). There the Court held that the prosecutor’s use of “testimonial” hear-say violates the Confrontation Clause unless the declarant is unavailable and the defendant had a prior opportunity to cross-examine the declarant. Looking at the text of the clause, the Court found that a “witness against” an “accused” is someone who “bears testimony,” a definition that does not apply to everyone who utters hearsay. Drawing on history, the Court found that the principal concern of the Confrontation Clause was the use of ex parte “testimony”—such as depositions, affidavits, or statements made by witnesses under government interrogation—against an accused. Hence, the Court held that “testimonial” hearsay is inadmissible against a criminal defendant who has no opportunity to confront and cross-examine the declarant, while the use of other hearsay is not affected by the Confrontation Clause.

Since Crawford, in a series of cases, the Court has defined “testimonial” hearsay to include formal testimony under oath (like depositions and affidavits), “structured” police interrogation, and other statements made for the “primary purpose” of providing evidence for criminal prosecution. Hearsay statements made for other purposes, like 911 calls for emergency assistance, are not “testimonial” and therefore not excluded from evidence by the Confrontation Clause. In Melendez-Diaz v. Massachusetts (2009), the Court held that certificates of analysis reporting the results of forensic laboratory tests were testimonial statements made for the purpose of providing evidence for criminal prosecution. The practical effect of the Melendez ruling has been to require live testimony from laboratory analysts regarding drug, blood, DNA, and other forensic testing. Several recent cases suggest that the justices have developed differing views on the breadth of the clause. Justice Clarence Thomas would apply the clause narrowly to reach only “formal” testimony (like depositions or affidavits) or its equivalent. Justice Samuel Alito has suggested that “testimonial hearsay” includes only statements made with a primary purpose of accusing a “targeted individual,” rather than the broader range of statements made to police investigating a crime. The majority of the Court continues to apply the clause to any hearsay statement made for the “primary purpose” of criminal prosecution.

The Court has limited the right to face-to-face confrontation in extraordinary cases. In Maryland v. Craig (1990), the Court allowed a child witness to testify by closed-circuit television without physically entering the courtroom because the child was emotionally unable to testify in the defendant’s presence. The Court found that the process nevertheless satisfied the Confrontation Clause because it allowed for cross-examination and for the jury, defendant, and counsel to observe the demeanor of the child while she testified.