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 decision- only 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." 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. 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.
Constitutional Evidence Law,
61 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vlr/vol61/iss1/2