Brady Rule

In Brady v. Maryland, 373 US 83 (1963), the US Supreme Court set forth the government's duty to disclose exculpatory evidence to a criminal defendant, a holding that thus became known as the Brady rule. In Brady, the defendant had been convicted of complicity in a murder, which had occurred during the course of a robbery, and was sentenced to death. In the years following Brady, the Supreme Court clarified the parameters of the disclosure rule. Specifically, in Giglio v. United States, 405 US 150 (1972), the Court expanded the definition of "favorable evidence" to include evidence that could be used to attack the credibility of a witness against the accused (impeachment evidence). Accordingly, to comply fully with the Brady rule, the prosecution often need only disclose available impeachment evidence immediately prior to the testimony of the relevant witness, and need only provide exculpatory evidence in time for the defendant to make some beneficial use of it at trial.