Convictions Based on Lies: Defining Due Process Protection
The corrupting impact of false testimony on the justice system is profound and corrosive. The Supreme Court has long-since held that the due process clause protects against convictions based on testimony that the prosecutor knew or should have known was false.
Despite this precedent, courts have undermined that constitutional protection by imposing demanding requirements of prosecution knowledge, narrowing the definition of false testimony, and holding defendants to an inappropriate standard of materiality. As a result, the law does not provide adequate protection from conviction based on lies.
Courts must reinvigorate this area of the law. To provide appropriate protection, the requirements a defendant must meet to receive relief based on the use offalse testimony must be clarified in the following ways. First, the prosecution should be deemed to have knowledge of the falsity not only if an individual prosecutor had actual knowledge, but also if the prosecution did not meet its duty to discover that the testimony was false or if the prosecution had knowledge of contrary information possessed by other government actors and therefore imputed to the prosecution. Second, the false testimony need not rise to the level of perjury. Third, the courts should apply the more lenient standard of materiality defined for false testimony cases by asking how the revelation that the witness had testified falsely would have influenced the jury in the initial trial rather than asking what would have occurred had the witness simply given truthful testimony.
In addition, the courts should revisit the law that applies when a defendant discovers that the prosecution unknowingly presented false testimony. If the falsity was material, the courts should conclude that the conviction violates due process despite the lack of prosecution knowledge. Even if the courts do not extend due process protection to the unknowing use offalse testimony, they should grant the defendant a new trial more readily than with other types of newly discovered evidence. The corrupting impact offalse testimony calls for at least this level of protection.
Anne Poulin. "Convictions Based on Lies: Defining Due Process Protection" Penn State Law Review 116 (2011): 331.