The Brady rule, named after Brady v. Maryland, requires prosecutors to disclose material, exculpatory information in the government's possession to the defense. Brady material, or the evidence the prosecutor is required to disclose under this rule, includes any information favorable to the accused which may reduce a defendant's potential sentence, go against the credibility of an unfavorable witness, or otherwise allow a jury to infer against the defendant’s guilt.
Initially, the Brady rule was only applicable if the defendant made a pretrial request for specific information which the prosecution denied. In United States v. Bagley, however, the Supreme Court eliminated this request requirement and stated that the prosecution has a constitutional duty to disclose all material, favorable information in their possession to defendants regardless of whether it is requested. This duty is breached regardless of whether that information is withheld intentionally or unintentionally.
If a Brady rule violation is discovered during trial, the court can either declare a mistrial or prohibit the prosecution from using unfavorable evidence which could be discredited by the withheld information. Because the Brady rule inherently involves a lack of information on the side of the defense, however, violations of the Brady rule are typically only discovered after the defendant is already convicted. As a result, the most common outcome of a Brady rule violation is overturning that conviction. Additionally, if the prosecution withheld Brady material intentionally or knowingly, they may be subject to sanctions.
The defendant bears the burden to prove that any withheld information was both material and favorable. A defendant meets this burden if they can show that there is a reasonable probability that the outcome of the trial would have been different had the information been disclosed. In Kyles v. Whitley, the Supreme Court clarified four aspects of this test:
[Last updated in January of 2023 by the Wex Definitions Team]