The Brady Rule traces its origins to the early 1960s, during a period when the U.S. Supreme Court was particularly focused on strengthening the rights of individuals accused of crimes. The case of Brady v. Maryland involved John Leo Brady, who was convicted of first-degree murder and sentenced to death. During the trial, Brady admitted his involvement in the crime but claimed that his co-defendant, Donald Boblit, had actually committed the murder. Brady's defense requested access to Boblit’s statements, but the prosecution withheld a key statement in which Boblit admitted to the killing. The withheld statement was clearly exculpatory as it supported Brady’s argument that he was not the principal actor in the murder.
After discovering the withheld evidence, Brady’s attorneys appealed, arguing that the prosecution's failure to disclose the statement violated Brady's right to due process. The Supreme Court agreed, ruling that suppression of evidence favorable to the accused upon request violates due process when the evidence is material to guilt or punishment. This ruling laid the foundation for what is now known as the Brady Rule.