Constitutional Evidence Law

This Article identifies the causes and consequences of a puzzling asymmetry in constitutional law. Of the three facets of adjudicative fact-finding-evidence, procedure, and rules of decision-only two are constitutionalized. Constitutional law regulates procedural and decisional rules-not whether the evidence that fact-finders use is adequate. Allocation of the risk of error by procedures and decisional rules-formulated as burdens of proof-is subject to constitutional scrutiny. Allocation of the risk of error by the rules of evidential adequacy, however, is free from that scrutiny. This constitutional asymmetry is puzzling because all risk-allocation impacts court decisions and, consequently, whether a person is deprived erroneously of her liberty or property. This Article explains this asymmetry in the informal constitutionalization of evidence-a phenomenon that implicates three dynamics of power and culture. First, state evidence rules generally align with the Supreme Court's agenda for risk-allocation. Second, when those rules do deviate from the Court's agenda to promote local interests, they do not do so overtly. Finally, a state rule's alignment with a federal rule of evidence guarantees its constitutionality. This informal order reflects a series of implicit, but credible understandings between state courts and the Supreme Court. This Article identifies and illustrates these understandings. INTRODUCTION This Article identifies the causes and consequences of a puzzling asymmetry in constitutional law. Of the three facets of adjudicative factfinding-evidence, procedure, and rules of decisiononly two are constitutionalized. Constitutional law regulates procedural and decisional rules, but not whether the evidence that factfinders use is adequate. Constitutional law regulates procedure through a set of rules that determine a person's power to control the trial by adducing evidence in support of her case and by examining the evidence of her adversary. Constitutional law regulates decisionmaking by setting probability requirements for findings of fact-standards of proof-and by allocating the burdens of proof among the prosecution, plaintiffs, and defendants. Constitutional law, however, does not control adequacy of the evidence upon which factfinders determine the probability of contested allegations and apply the burdens of proof. This is so because the Supreme Court interprets the Due Process Clause, as related to evidence, very narrowly. Under this interpretation, any evidence is constitutionally adequate when its use is not "fundamentally unfair."1 Moreover, "fundamental unfairness" occurs only in extreme cases such as those which exhibit a serious prosecutorial misuse of the trial process. Examples include when the government knowingly procures the defendant's conviction by false evidence or by evidence from which factfinders can draw no rational inferences.2 Anything less is not "fundamentally unfair." As a result, virtually any rule that controls evidential admissibility and identifies evidence that does or does not require corroboration is constitutional. The "fundamental unfairness" criterion practically exempts evidential adequacy from constitutional scrutiny. Under this regime, as long as factfinders apply the "beyond a reasonable doubt" standard, they can convict a defendant upon any inculpating evidence. This evidence may include the defendant's uncorroborated confession,3 uncorroborated testimony of the defendant's accomplice, a DNA statistic, or even the defendant's prior crimes. Evidential insecurity would not make the verdict unconstitutional,4 as constitutional scrutiny only applies to evidence implicating the defendant's participatory powers under the Sixth Amendment. A rule that blocks the admission of defense evidence might detract from the defendant's right to compulsory process. A rule that allows factfinders to rely on hearsay statements as evidence against the defendant might detract from the defendant's right to confrontation. …