Which landmark Supreme Court case established that the prosecution must turn over all exculpatory evidence to the defense?

• A. Gideon v. Wainwright
• B. Brady v. Maryland
• C. Miranda v. Arizona
• D. Mapp v. Ohio

Answer: (B)

The central idea is that prosecutors must disclose evidence that could help the defense. In Brady v. Maryland, the Supreme Court ruled that failing to turn over exculpatory evidence violates due process when that evidence is favorable to the defendant and material to guilt or punishment. Exculpatory evidence includes any information that could exonerate the defendant or undermine a key prosecution claim, such as alibi details or statements that impeach a witness. The standard is materiality: there must be a reasonable probability that the outcome would have been different if the evidence had been disclosed. This rule protects fair trial rights and helps prevent wrongful convictions. Other famous cases deal with different protections—right to counsel and interrogation warnings, or the exclusionary rule for illegally obtained evidence—so they don’t address the prosecution’s duty to disclose exculpatory material.