In Brady v. Maryland, the United States Supreme Court concluded that a defendant was entitled to material and exculpatory material that the prosecution possessed. Because of this case, both public defenders and criminal justice officers refer to this as "Brady Material" or "The Brady Rule."
The court cited Solicitor General Judge Simon E. Sobeloff who put the idea as follows in an address before the Judicial Conference of the Fourth Circuit on June 29, 1954:
"The Solicitor General is not a neutral; he is an advocate, but an advocate for a client whose business is not merely to prevail in the instant case. My client's chief business is not to achieve victory, but to establish justice. We are constantly reminded of the now classic words penned by one of my illustrious predecessors, Frederick William Lehmann, that the government wins its point when justice is done in its courts."
Brady Material is any evidence which, if believed, would be favorable to the defendant..
It includes at least three types of evidence
- Exculpatory Evidence - Evidence which would tend to make an affirmative demonstration of the defendant's innocence or negate evidence of guilt.
- Mitigation Evidence - Evidence which would reduce the degree of guilt from one class of crimes to another (for instance, from first degree murder to voluntary manslaughter) or would in some other way reduce the defendant's sentence.
- Impeachment Evidence - Evidence that diminishes the credibility of a prosecution or defense witness. This includes any deals made between the prosecutor and a witness.
Materiality under Brady
In United States v. Bagley  the Supreme Court concluded that a defendant's conviction should be reversed if the prosecutor failed to turn over "Brady Material" and there is a "reasonable probability that, had the evidence been disclosed to the defense, the result of the proceedings would have been different." In 1999, the Supreme Court summarized the Bagley Rule as having three elements:
- The evidence at issue must be favorable to the accused, either because it is exculpatory, or because it is impeaching
- That evidence must have been suppressed by the State, either willfully or inadvertently
- Prejudice must have ensued.
Prosecutor's Duty under Brady
Because the prosecutor represents the entire government, she has a duty to learn of any favorable evidence known to other government agencies. Once all this material has been collected, the prosecutor must make a determination as to whether any piece of evidence alone, or in conjunction with other evidence, requires disclosure.
Brady Material and Police Misconduct
One issue which still appears unresolved is whether the prosecution has a duty to disclose prior police misconduct as "Brady Material." Proponents of this kind of discovery contend that if the defense raises police misconduct as a defense to a crime, prior bad conduct of the officer becomes material and exculpatory as impeachment evidence.
Opponents contend that permitting extensive discovery from the police officer's personal file would violate the officer's right to privacy and distract the court from the determination of guilt or innocence by turning the proceedings into a test of the officer's credibility.
Many states, such as California, permit limited "in camera" review of an officer's private personal file. The judge will then make a determination as to whether any evidence inside is material and exculpatory. When the evidence is released, it is sometimes done under a protective order.
- Brady v. Maryland, 373 U.S. 83 (1963)
- See Dennis, Maryland's Antique Constitutional Thorn, 92 U. of Pa.L.Rev. 34, 39, 43; Prescott, Juries as Judges of the Law: Should the Practice be Continued, 60 Md.St.Bar Assn.Rept. 246, 253 254.
- United States v. Bagley, 427 U.S. 97 (1976)
- Giglio v. United States, 405 U.S. 150 (1972)
- United States v. Bagley, 473 U.S. 667 (1985)
- Stickler v. Greene, 527 U.S. 263 (1999)