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.