Reconceiving the right to present witnesses.

• Date: 01 March 1999
• Author: Nagareda, Richard A.

INTRODUCTION

Modern American law is, in a sense, a system of compartments. For understandable curricular reasons, legal education sharply distinguishes the law of evidence from both constitutional law and criminal procedure. In fact, the lines of demarcation between these three subjects extend well beyond law school to the organization of the leading treatises and case headnotes to which practicing lawyers routinely refer in their trade. Many of the most interesting questions in the law, however, do not rest squarely within a single compartment; instead, they concern the content and legitimacy of the lines of demarcation themselves. This article explores a significant, but relatively neglected, area that lies at the intersection of evidence, the Constitution, and crime.

For more than three decades, the Supreme Court has recognized a constitutional right on the part of criminal defendants to present witnesses.(1) Although this right is not set forth explicitly in the text of the Constitution itself, the Court correctly has regarded it as a necessary implication of the Compulsory Process Clause of the Sixth Amendment.(2) As such, the right is an integral part of the constitutional guarantees that a criminal defendant may invoke to override the ordinary rules of evidence, whether in the form of statutes or common law decisions -- in essence, to turn a dispute within the law of evidence into a constitutional case.(3)

The right to present witnesses, however, tends to slip through the cracks of the conventional curriculum. Given its limitation to criminal trials, the right does not come up in standard constitutional law courses; nor, given its evidentiary overlay, does it arise in standard criminal procedure courses. Even within the realm of evidence pedagogy, the right barely achieves mention. With rare exception, the editors of the leading evidence casebooks do not discuss the major Supreme Court decisions on the right as a distinct line of analysis.(4) They typically content themselves, instead, to include a single decision in the line and, even then, to focus largely upon the particular kind of testimony in dispute.(5) This omission is one of many that results from the curricular compartmentalization of the Constitution and that, in turn, carries over into the world of legal scholarship.(6) This article seeks, if nothing else, to build the case to rectify this omission.

It comes as no surprise that the Court has invoked the right in order to strike down the application of evidence rules that peculiarly disadvantage criminal defendants with regard to the presentation of witness testimony.(7) More surprisingly, the Court also has invoked the right to invalidate, as applied to criminal defendants, at least some rules of evidence that are generally applicable -- that is, rules that restrict the admission of a particular type of witness testimony, whether offered by the prosecution or the defense.(8) Under the Court's current approach, evidence rules that operate to prevent the presentation of defense witnesses "may not be arbitrary or disproportionate to the purposes they are designed to serve."(9)

This constitutional override to the ordinary rules of evidence has assumed even greater significance in recent years, as rulemakers have grappled increasingly with new forms of witness testimony that stem from developments in modern science. The Court's two most recent decisions on the right, for example, focused upon rules that categorically excluded, respectively, hypnotically-enhanced testimony(10) and expert scientific testimony concerning the results of polygraph examinations.(11) In these cases, the Court reached starkly divergent results, striking down the former rule as applied to a criminal defendant, but upholding the latter. Whatever its content, the right to present witnesses undoubtedly will play a key role in the disputes that are bound to arise from the science and technology of witness testimony in the twenty-first century.

The prospect of confronting the evidence disputes of the future within the parameters of the Court's current case law is not auspicious. As I explain, the Court's decisions in the area -- especially when read in light of the Court's most recent decision, from last Term, in United States v. Scheffer(12) -- form an incoherent, contradictory body of law. That, in itself, would be reason enough for commentators to concern themselves with the subject, which surprisingly has garnered little fresh attention in recent years. The mid-1970s saw substantial articles by two leading commentators Peter Westen and Robert Clinton -- on the then-developing right to present witnesses.(13) Indeed, the authors of a subsequent treatise on exculpatory evidence describe their work as "essentially an extended footnote to" the Westen and Clinton articles.(14) No commentator in the past two decades, however, has sought to question the conventional understanding of the right as a matter of first principles. Nor has anyone sought to integrate the Court's recent thinking on the subject with contemporary scholarship on other, conceptually similar questions of constitutional law that lie outside the compartments of evidence and criminal procedure.(15) These are the objectives of this article.

To that end, I contend that the Court's "arbitrary or disproportionate" standard is not simply flawed in application but that the standard fundamentally misconceives the nature of the right to present witnesses. Under the Court's current approach -- indeed, in the view of all modern commentators -- the right consists of an entitlement to exceptions from generally applicable rules of evidence, though the actual availability of an exception in a given instance has tended to turn recently upon ad hoc judgments by the Court itself.

One should not dismiss the ad hoc nature of the Court's recent jurisprudence simply as a sign of sloppy judging or ideological sleight-of-hand; rather, one should see it as a symptom of a much deeper and well-founded discomfort on the part of the Court with the implications that an "arbitrary or disproportionate" standard would have for the law of evidence, if taken seriously. The conception of a constitutional right as an entitlement to exceptions from generally applicable rules raises what one commentator aptly describes, in other constitutional contexts, as "the floodgates problem"(16) namely, the challenge of articulating some principled stopping point for the recognition of exceptions in order to avoid tearing apart the system of rules itself. It is this problem, I submit, that best accounts for -- though it does not justify -- the Court's ad hoc reasoning on the right to present witnesses. An exception-based view of the right to present witnesses, in particular, would throw into doubt such familiar features of evidence law as the rule against hearsay, limitations upon the use of extrinsic evidence for purposes of witness impeachment, and rules of privilege.

In describing the Court's recent output in these terms, I seek to highlight still another kind of compartmentalization -- one within the realm of constitutional law. Many of the rights protected by the Constitution consist of either entitlements to exceptions or demands for equal treatment. To take a well-settled example, the holding of Washington v. Davis(17) is that a generally applicable law does not violate the Equal Protection Clause merely because it has a disproportionate impact upon the members of a racial minority there, African Americans. This is so because the content of the constitutional right -- as its name suggests m is itself equality-based, not exception-based. What compartment one is in thus has tremendous significance for the application of the Constitution. It is not surprising, then, that one of the most controversial constitutional decisions in recent years -- the Court's 1990 decision in Employment Division v. Smith(18) on the Free Exercise Clause consists, at bottom, of a determination to switch a constitutional right from one compartment to the other. The upshot of Smith is to reject the preexisting understanding of the Free Exercise Clause as an entitlement to exceptions for religious practice(19) in favor of a view that makes religious practitioners subject to generally applicable laws -- there, a criminal prohibition upon possession of the drug peyote.(20)

The switch effected by Smith understandably has elicited a wealth of academic commentary(21) -- not to mention an unsuccessful congressional effort to switch back, by statute, to an exception-based view.(22) But scholars have devoted comparatively little attention to the even more provocative project of identifying areas in which the Court has erroneously declined to switch a constitutional right from the exception to the equality compartment. The right to present witnesses, I submit, is a striking example of such an error. Specifically, I argue that a wide array of sources -- the historical context of the Compulsory Process Clause, recent learning on the closely related Confrontation Clause, considerations of institutional structure, the Court's approach to conceptually similar problems of constitutional law, and sheer practical concern for the protection of criminal defendants as a whole -- together form a compelling case to reconceive the right as one of equal treatment. Under the approach set forth here, the Court should apply strict scrutiny -- in the familiar sense of a demand for a compelling governmental interest -- with respect to evidence rules that peculiarly disadvantage criminal defendants. By contrast, when the rule in question is an evenhanded one -- when the government, as rulemaker, has determined to restrict the presentation of witness testimony by the government itself as prosecutor in the same manner as it limits the defense at trial -- the Court generally should apply the far more deferential standard of ordinary rationality...