Compulsory Process Clause

In all criminal prosecutions, the accused shall enjoy the right to... have compulsory process for obtaining witnesses in his favor....

Amendment VI

For centuries, Britons had struggled against the common-law rule that forbade an accused from calling witnesses in his defense in cases of treason or felony, or, even when allowed, not to permit the defense witness to be sworn under oath. The common-law rule survived in the American colonies even after England had abolished it by statute. After the Revolution, however, a number of state constitutions established in one form or another the right to call defense witnesses. When the First Congress considered the Compulsory Process Clause, there was little debate over its value, and it became part of the Sixth Amendment without opposition. The clause assured that the accused in a criminal case was guaranteed not only the right to call witnesses but also a process to obtain witnesses, so that defense evidence could be evaluated by a jury or, in a nonjury criminal case, by a judge. It was, in sum, an essential part of the right of an accused to present a defense.

The Supreme Court had little opportunity to interpret the Compulsory Process Clause and explain its meaning prior to 1967, when the Court ruled in Washington v. Texas that the clause was so fundamental to a fair trial that it was part of the Fourteenth Amendment's Due Process Clause and therefore binding on the states as well as on the federal government. Washington v. Texas also expanded the reach of the clause by holding unconstitutional a Texas penal statute that permitted the government to offer the testimony of one charged as a principal, accomplice, or accessory, but barred a defendant from calling the same person unless that person had been previously acquitted of the charges. The rationale for the disadvantage imposed upon defendants was that defendants would attempt to exculpate each other, and thus their testimony would be inherently biased and untrustworthy. The Supreme Court had upheld a similar rule in federal trials in United States v. Reid (1852), before changing its mind and rejecting the rule for federal trials in Rosen v. United States (1918). Although Rosen was not a constitutional ruling, the Court adopted its position in Washington v. Texas as binding under the Compulsory Process Clause, reasoning that "it could hardly be argued that a State would not violate the clause if it made all defense testimony inadmissible as a matter of procedural law." Furthermore, the Court declared that "[i]t is difficult to see how the Constitution is any less violated by arbitrary rules that prevent whole categories of defense witnesses from testifying on the basis of a priori categories that presume them unworthy of belief."

The Court has had few occasions since to deal with the clause. Green v. Georgia (1979) held that it was an error for a state court to exclude a codefendant's confession offered by a defendant in a capital sentencing proceeding where the prosecution had relied on a codefendant's confession at his own trial. In United States v. Valenzuela-Bernal (1982), the defendant complained that the government had violated his rights under the clause when it deported potential alien witnesses; the Court ruled that the defendant must show that the testimony of the deported aliens would have been favorable and material. In Rock v. Arkansas (1987), the Court held that a per se rule excluding all hypnotically refreshed testimony impermissibly infringed on a criminal defendant's right to testify on her own behalf.

Unlike other Sixth Amendment guarantees, the right to call witnesses is totally at the defendant's initiative. It is not unlimited, but subject to reasonable restrictions. Taylor v. Illinois (1988). The ordinary rules of evidence apply to the exercise of the right. The Compulsory Process Clause, for example, does not guarantee a defendant the right to use polygraph evidence in a jurisdiction that forbids such evidence. United States v. Scheffer (1998).

Profile photo of Stephen Saltzburg
Stephen Saltzburg
Wallace and Beverley Woodbury University Professor of Law
Co-director, Litigation and Dispute Resolution Program
The George Washington University Law School