523 U.S. 303 (1998), Supreme Court of the United States
United States v. Scheffer is a cornerstone Supreme Court decision at the intersection of evidence law, constitutional criminal procedure, and military justice.
Does M.R.E. 707's categorical exclusion of polygraph evidence in courts-martial violate a criminal accused's Sixth Amendment right to present a defense (and related due process guarantees)?
Rulemakers have broad latitude to promulgate evidentiary rules that serve legitimate interests in the criminal process. Although the Constitution guarantees a meaningful opportunity to present a complete defense, evidentiary exclusions will be upheld so long as they are not arbitrary or disproportionate to the purposes they serve and do not infringe upon a weighty interest of the accused. See, e.g., Washington v. Texas; Chambers v. Mississippi; Rock v. Arkansas. A per se exclusion of a category of evidence is constitutionally permissible where reasonable doubts persist about its reliability, where admission threatens to undermine the jury's role in credibility determinations, and where admission would spawn collateral litigation that distracts from the merits.
No. The per se ban on polygraph evidence in courts-martial under M.R.E. 707 does not violate the Sixth Amendment or due process. The Supreme Court reversed the Court of Appeals for the Armed Forces and upheld the rule's constitutionality.
Scheffer is a leading case on the constitutional limits of evidentiary exclusions. It teaches that the Sixth Amendment's right to present a defense yields to categorical rules when justified by legitimate concerns about reliability, juror confusion, and trial management. The decision also highlights judicial deference to rulemakers—Congress, the President (in military justice), and courts—in calibrating admissibility standards, especially for controversial scientific evidence. For law students, Scheffer provides a template for analyzing defense challenges to evidence rules: identify the constitutional right, articulate the government's interests, assess arbitrariness/disproportionality, and compare to precedents like Washington, Chambers, and Rock. Practically, Scheffer cements the inadmissibility of polygraph evidence in courts-martial and signals caution for civilian courts confronting novel or contested expert techniques. It underscores the centrality of the jury's role in credibility determinations and the judiciary's gatekeeping function in protecting that role.