Brady, Giglio & Agurs: Prosecutorial Disclosure Rules

Introduction to Prosecutorial Disclosure

Several Supreme Court cases have clarified that prosecutors must reveal evidence to the defense that could be favorable to the defendant. These cases have established legal precedent that governs such disclosure and provided the underlying logical basis for it.

Brady v. Maryland (1963)

The 1963 case Brady v. Maryland was one of the first to establish this rule. In this case, Brady and a companion named Boblit were convicted of first-degree murder and sentenced to death. Brady admitted that he participated in the murder but argued that Boblit had done the actual killing. During the original trial, Brady's guilty plea was entered with a request that the jury not return a capital sentence, but they did so anyway. This outcome prompted Brady to petition prosecutors to review Boblit's extrajudicial statements.

All but one of those statements was revealed. The one that was withheld contained Boblit's admission that he had done the killing. This statement was not disclosed until after Brady had been convicted, sentenced, and his conviction affirmed on appeal. Brady petitioned for a retrial on the basis of this newly discovered evidence. The initial trial court ruled against the petitioner, but the appeals court held that Brady's right to due process had been violated by the withholding of this evidence. The Supreme Court sided with the appeals court and ordered a retrial limited to the question of punishment. The Brady case was considered an extension of Mooney v. Holohan, in which the Court had also ruled on what forms of nondisclosure violate due process.

The Brady decision substantially strengthened Fifth Amendment due process protections by ensuring that prosecutors cannot withhold key evidence. The suppression of evidence favorable to the defendant was deemed a violation of the defendant's right to a fair trial. The case has since been used to discredit law enforcement officers with a history of lying or withholding evidence. Although the presumed credibility of law enforcement has long been a cornerstone of criminal trials, Brady was among the earlier instances where demonstrable Fifth Amendment violations by law enforcement were formally recognized. The credibility of other witnesses has also come into question as a result of this ruling — even the suspicion that a witness might be withholding something can undermine their credibility at trial.

Giglio v. United States (1972)

Giglio v. United States was a 1972 case that built upon the foundation established by Brady. In Giglio, government prosecutors had promised leniency to a witness in exchange for his testimony. The key witness for the prosecution was Taliento, a co-conspirator who had participated with Giglio in ongoing bank fraud. Federal prosecutors promised Taliento that he would not face prosecution if he testified before the grand jury and at trial. Without Taliento's testimony, the case against Giglio would have been substantially weaker. However, neither the grand jury nor the trial jury was informed of this arrangement.

The Court held that the prosecution's failure to inform the defense of this deal constituted a breach of due process. This was a significant extension of due process protections, given that witnesses in many cases are co-conspirators who receive various immunities, protections, or favorable deals in exchange for their testimony. After Giglio, such arrangements must be disclosed so that the defense may inform the judge and jury of the incentive the witness has to testify. This information may then be used to challenge the credibility of that witness. A new trial was ordered.

This ruling was particularly important because Taliento's testimony was the sole basis upon which an indictment — let alone a conviction — had been possible. The credibility of the witness was therefore a critical element of the entire proceeding, and any information bearing on that credibility was deemed material to the case.

Conclusion: The Brady Framework and Its Limits

The Brady ruling established the prosecutorial duty to disclose material information. The Giglio and Agurs rulings set out some of the limits of this rule. Brady established that law enforcement credibility is paramount, particularly where officers might withhold valuable information — they are compelled to disclose such information to the defense. Giglio established that where a witness has made a deal with the prosecution in exchange for testimony, the defense must be informed. Agurs defined the limits of what constitutes material information, establishing that only the nondisclosure of significant information is grounds for a retrial, and that the criminal history of a victim is not automatically material — even in cases where the defense is claiming self-defense.

Together, these three cases form the core of the Brady disclosure framework in American criminal procedure, balancing the prosecution's investigative advantages against the defendant's constitutional right to a fair trial.