[1]: 4  Thirteen years later, the Supreme Court defined what it meant for evidence to be material in a case called United States v. Agurs (1976).

[2] Hughes Anderson Bagley was indicted on 15 counts of violating federal narcotic and firearm statutes in the Western District of Washington in October 1977.

In preparation for trial, to be held in December, Bagley's counsel filed a discovery motion that requested information on the witnesses the prosecution intended to call, their criminal records, and any promises made to them in exchange for testimony.

[3] At Bagley's bench trial, two state law-enforcement officers (James F. O'Connor and Donald E. Mitchell) testified as the prosecution's principal witnesses.

[4] In 1980, while incarcerated for the narcotic charges, Bagley filed a Freedom of Information Act request and received response copies of ATF contracts that the principal witnesses had signed three years prior.

[5] The District Court, in denying to vacate Bagley's sentence, had found that had the existence of the agreements been disclosed during trial, the disclosure would have had no effect upon its finding that the Government had proved beyond a reasonable doubt that respondent was guilty of the offenses for which he had been convicted.

[6] The court then noted that the District Judge who had presided over the bench trial concluded beyond a reasonable doubt that disclosure of the ATF agreement would not have affected the outcome.

[7] The Court of Appeals, however, stated that it disagreed with this conclusion, in particular, with the Government's premise that the testimony was exculpatory on the narcotics charges, and that Bagley therefore would not have sought to impeach "his own witness."

The Blackmun opinion characterized the Court of Appeals reversal as having been based on the theory that the Government's failure to disclose the requested Brady information that respondent could have used to conduct an effective cross-examination impaired respondent's right to confront adverse witnesses, as the Court of Appeals opinion had concluded by saying: "[W]e hold that the government's failure to provide requested Brady information to Bagley so that he could effectively cross-examine two important government witnesses requires an automatic reversal.

[3] The three signed onto the new "reasonable probability" standard discussed in Part III but did not join the Blackmun opinion's statements regarding specific requests.

[20] Bagley has been criticized by scholars for requiring prosecutors to make disclosure decisions based upon their post-hoc view of how the trial will go.