The Brady Rule requires the prosecution to disclose to the defense any evidence that is material and favorable to the accused. This includes evidence that may exonerate the defendant, reduce the defendant’s potential sentence, or otherwise affect the outcome of the trial. The rationale behind this rule is to ensure a fair trial, as guaranteed by the Due Process Clause of the Fourteenth Amendment. The prosecution's failure to disclose such evidence, whether intentional or inadvertent, constitutes a Brady violation.
Materiality of Evidence
For evidence to be considered under the Brady Rule, it must be "material." Evidence is deemed material if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different. The Supreme Court has clarified that "reasonable probability" does not mean that the defendant would more likely than not have received a different verdict but rather that the likelihood of a different outcome is sufficient to undermine confidence in the verdict.