United States v. Bagley
United States Supreme Court
473 U.S. 667 (1985)
Before trial, Bagley (defendant) requested disclosure of any deals made with prosecution witnesses, and the government provided affidavits from two key witnesses denying any deals; after Bagley's conviction, he discovered through FOIA requests that both witnesses had actually signed $300 contracts to testify. Bagley argued this withheld impeachment evidence violated due process, the district court found it immaterial since the outcome would have been the same, and the court of appeals reversed based on automatic Brady reversal, prompting Supreme Court review.
Whether, under Brady, the prosecution's failure to turn over favorable evidence requires a new trial only if a reasonable probability exists that the outcome would have been different had the evidence been disclosed.