Right to Compulsory Process
The U.S. Constitution's Compulsory Process Clause guarantees criminal defendants a "compulsory process for obtaining witnesses in his favor." Despite its prominent placement in the Sixth Amendment, the Compulsory Process Clause remained virtually dormant for more than 150 years, rarely called upon by either defendants or the US Supreme Court.
At common law, the Compulsory Process clause was considered limited in scope; it merely provided the defendant the right to use the government's service of process to forcibly produce witnesses at trial. However, one of the first cases decided on Compulsory Process grounds, United States v. Burr, hinted at a much broader interpretation of the clause. In Burr, a Supreme Court decision written by Chief Justice John Marshall, the Court held that the Compulsory Process Clause permitted defendant Aaron Burr to serve a subpoena duces tecum (i.e. to appear and produce evidence) for certain letters of the President of the United States. He argued that the letters might be material to his defense and their production was required under the Compulsory Process Clause.
The government objected, arguing that Compulsory Process only permitted the forced presentation of witnesses and not their documents. Justice Marshall, in his decision in favor of Burr, dismissed the distinction between persons and their papers and concluded that materiality could be satisfied by a demonstration that "there exist[s] any reason for supposing that the [subpoenaed] testimony may be material . . . ." Further, Marshall dismissed the argument that Burr's discovery motion could never be material because Burr had no knowledge of what the letters would eventually say, calling this limiting interpretation of Compulsory Process, "unreasonable."
Despite the implications of U.S. v. Burr, the Compulsory Process Clause was largely dormant for the next 100 years, with many similar cases decided on Due Process or Confrontation Clause grounds. Despite the dearth of cases deciding the scope and meaning of the Compulsory Process Clause, however, nearly ever state incorporated Compulsory Process into their own constitutions.
Expanding notions of Compulsory Process
One of the earliest modern applications of the Compulsory Process clause was provided in Washington v. Texas, 388 U.S. 14 (1967), when the Supreme Court struck down a rule of evidence barring accomplice testimony and first declared the Compulsory Process Clause applicable to the states through the Due Process Clause of the Fourteenth Amendment. The court claimed the Compulsory Process Clause invalidated a rule that arbitrarily denied a defendant "the right to present a defense" by presenting material, competent witnesses who had first-hand knowledge of the events.
A few years later, in Chambers v. Mississippi, 410 U.S. 284 (1973), the Supreme Court was asked to decide whether a hearsay rule could potentially violate the Due Process Clause by preventing a witness from testifying about exculpatory material. In Chambers, a defendant on trial for murder attempted to present evidence of a third party's written admission to the crime. However, the defense witness repudiated on the stand and provided an alibi. The defendant was not permitted to cross-examine his own witness under Mississippi's evidence rules. The defendant then attempted to present evidence that the witness had confessed to the crime; however, this too was excluded on grounds that it violated the hearsay rule. The Supreme Court reversed the conviction, stating in part that "where constitutional rights directly affecting the ascertainment of guilt are implicated, the hearsay rule may not be applied mechanistically to defeat the ends of justice." The decision, though decided on Due Process grounds, nonetheless mirrored the arguments made in Washington v. Texas.
Modern Application of Compulsory Process: Holmes v. South Carolina
In the Supreme Court's most recent case in the area, Holmes v. South Carolina, 547 U.S. 319 (2006), Justice Alito, in his first decision as a Supreme Court Justice, crafted an opinion that struck down a South Carolina procedural rule on grounds that it violated the Compulsory Process Clause of the Sixth Amendment. Originally, the Gregory Rule permitted trial judges to exclude evidence if they felt it would be unfairly prejudicial, confusing or misleading for the jury. In a later decision, the South Carolina Supreme Court expanded the Gregory Rule, holding that evidence of a third party's guilt should be inadmissible if there was strong evidence of the defendant's guilt.
In striking down South Carolina's rule, the Supreme Court stated that the right to Compulsory Process guarantees criminal defendants "a meaningful opportunity to present a complete defense." These guarantees are violated by any rule of evidence that is "arbitrary" or "disproportionate to the purpose they are designed to serve." Therefore, while the Gregory Rule may appear facially constitutional, it is defeated when blind obedience to the rule controverts the truth-seeking function of evidence.
This conclusion was based on two factors. First, the Gregory Rule, as applied, did not examine the credibility of the witnesses or the reliability of the evidence. Second, the rule, ostensibly designed to exclude logically weak evidence, did not examine the witness' statements in themselves. As a result, the rule unconstitutionally infringed on the defendant's right to Compulsory Process.
Instead, the court concluded they must be weak of evidence of guilty was strong. This new rule provided at least one guide to balancing rules of evidence and privilege against the defendant's right to Compulsory Process. First, the question must be asked whether the rule of evidence rationally serves evidence's truth-seeking function. If not, the next question is whether the state has any other legitimate reason for establishing the rule.
Compulsory Process and discovery requests
A comparison of two Supreme Court cases illustrates the continuing confusion over which constitutional provisions should apply when a discovery request collides with a claim to privileged communications.
In Pennsylvania v. Ritchie, the court was asked to decide whether the Compulsory Process clause permitted a defendant to subpoena confidential records from a state child welfare agency in hopes of discovering witnesses, medical reports and other exculpatory evidence. The court admitted that past decisions had "little occasion to discuss the contours" of Compulsory Process. Rather than taking the opportunity to explore those contours, the Court simply admitted that it "never held squarely" on Ritchie's Compulsory Process claim that the clause permitted the defendant unlimited discovery of witnesses or exculpatory evidence. The court then proceeded to analyze the discovery ruling on the basis of Due Process. The case was ultimately remanded for a determination of whether material and exculpatory evidence was present in the files which would require a new trial.
However, while declining to rule on the defendant's Compulsory Process argument, the court admitted that some cases, like United States. v. Nixon, suggested that disclosure of documents might be required under Compulsory Process grounds. In United States v. Nixon, the court confronted the question of whether the President's generalized claim to confidential communications trumped a defendant's right to discovery. Citing Compulsory Process as one of the reasons for disclosure, they concluded that the defendant's right to evidence outweighed the President's generalized claim to confidentiality.
Limits of Compulsory Process
Compulsory Process is limited by two overlapping principles. First, the right to present witnesses may be restricted by a witnesses claim to privilege and the collision between the two will often require a weighing of the countervailing policies behind each provision. Second, Compulsory Process may itself be limited by Due Process.
Robert Weisberg has argued that Supreme Court decisions have generally failed at providing "reliable guidelines" for when a defendant's right to Compulsory Process will defeat a witness's claim to privilege. Similarly, Westen has argued that Compulsory Process may only defeat certain claims of privilege. For instance, there is an intractable tension between the defendant's right to Compulsory Process and the witness's right to assert his or her Fifth Amendment right against self-incrimination.
Privilege analysis is more difficult in the context of a subpoena duces tecum for evidence from an officer's personnel file. First, the officer's generalized claim of confidentiality has limited basis without a thorough investigation of the witnesses and documents in their personnel file. Only a thorough investigation can conclusively determine the ultimate materiality and credibility of the allegations.
Second, because an officer is a private individual "acting under color of state law" he is transformed into an agent of the state. Therefore, it is unclear whether the privilege asserted is his or the states. In either case, the privilege may be substantiated on separate but overlapping grounds. For the private individual, a claim of confidentiality is necessary to discourage timidity, embarrassment and harassment of the individual. From the state's point of view, improper disclosure of unsubstantiated claims undermines public confidence in the penal state.
No Compulsory Process violation can occur if the testimony or evidence is immaterial to a substantial issue of law. Westen, whose Compulsory Process I and Compulsory Process II, are seminal works in the field, has argued that Compulsory Process claims for witnesses should be divided into four categories -- competent witnesses, relevant witnesses, material witnesses and favorable witnesses - and that Compulsory Process is limited by these determinations. While such an analysis may makes sense in terms of compelling a witness to testify at trial, it makes little sense in compelling a witness to testify prior to trial for purposes of discovering potentially exculpatory material since the relevance, materiality or favorability of the evidence cannot be determined until it is disclosed and investigated. To demand a strict materiality standard for discovery would put the defendant in the same paradoxical situation that Burr found himself in when he attempted to subpoena letters from the President of the United States. The Supreme Court set forth what for some may be an unsatisfactory analysis of this problem in U.S. v. Valenzueala Bernal, when they held that Compulsory Process was not violated when U.S. government deported illegal aliens who could have provided testimony in favor of the defendant. The court held that, in order to prove a Compulsory Process violation, the defendant had to demonstrate that the testimony would have been material, favorable and not merely cumulative in nature. However, the court recognized that, because the illegal aliens had never been interviewed, the standard for materiality must be lower, otherwise the defendant would be caught in the paradoxical of having to prove materiality of testimony he does not possess. Nonetheless, the court concluded that the defendant had no Sixth Amendment violation until they made a "plausible explanation of the assistance he would have received from the testimony of the deported witnesses." The court distinguished this case from Burr, by concluding that the defendant's "knowledge of the truth" is the critical factor. In Burr, the defendant had no knowledge whatsoever of the letter's contents, whereas in Valenzueala Bernal the defendants had some knowledge of the witnesses testimony.
In practice, the right to confront witnesses also includes the right to compel the appearance of material witnesses. By virtue of Section 144 and 145 of the CPC a court may, on its motion, issue a summons compelling a person to appear and testify, or to produce documents in his custody. If the witness refuses to comply with the summons, the court may issue a warrant directing that the witness be brought before the court to testify.
A court may also issue a warrant to compel the attendance of a witness on the strength of evidence given under oath. See section 146 of the Constitution.