Concept
The Case-in-Chief Bar
Impeachment use and derivative evidence
The Case-in-Chief Bar
The rule that every later exception modifies concerns the prosecution's own proof. When police question a suspect in custody, the prosecution may not use what the suspect said unless it first shows that the required warnings were given and that the suspect validly waived the rights those warnings describe.1 The Court placed the burden of that showing on the prosecution: unless and until warnings and waiver are "demonstrated by the prosecution at trial," the statement cannot be used.2 The bar reaches exculpatory statements as well as incriminating ones, because it responds to the setting in which the statement was obtained.3
Each half of the rule has its own logic. Exclusion is the remedy because of what the Court found about custodial questioning: it carries inherently compelling pressures that undermine a suspect's will to resist, so the suspect must be effectively told of the privilege and the exercise of it must be honored.4 An instruction to give warnings, with no consequence for skipping them, would leave officers free to skip them whenever a statement looked more valuable than the risk. Attaching the consequence to the product the officers want, evidence the prosecution can offer, removes that temptation at the source. The allocation of the burden rests on a different reason. The interrogation room is closed, and the officers hold the only reliable record of what was said before the suspect began to talk. A suspect required to prove that no warnings were given would have to prove a negative about events that only the other side witnessed, so the proof task falls on the party that controls the evidence.
The facts of Miranda v. Arizona show what a violation looks like. Ernesto Miranda was arrested at his home and taken to a Phoenix police station, where the complaining witness identified him. Two officers then questioned him in an interrogation room, and they admitted at trial that they had never advised him of a right to an attorney. After two hours he signed a typed confession, and it was admitted over his objection.5 The sequence is the model case for the bar: unwarned questioning in a police-controlled room, a written product at the end, and a prosecution that offers the product to the jury as proof of guilt.
Change the order of events and the bar has nothing to exclude. In Gregg v. Georgia, a capital sentencing case whose Eighth Amendment holding is not at issue here, the defendant was arrested, received the Miranda warnings, and signed a written waiver of his rights before he signed a statement admitting the shootings.6 A prosecution in that position can carry the burden the rule assigns it, because the safeguards were in place before the defendant spoke. The two situations differ in one fact, whether warnings and a waiver came before the statement, and that fact decides whether the statement may form part of the prosecution's proof.
The wording of the exclusion carries a limit that later doctrine builds on. What Miranda removes is the statement from the prosecution's case in chief, the stage of trial at which the prosecution offers its own affirmative evidence of guilt. Whether the same statement may appear elsewhere in the trial, or may lead police to other evidence, is a separate question that the baseline rule does not answer by itself. A standard statement of the rule already records that qualification, noting that a defective statement cannot be used against the suspect at trial except for impeachment purposes.7 Impeachment is the first of a short list of recognized situations in which a statement taken without proper warnings can still matter, and the list also includes statements elicited in an emergency and answers to routine booking questions.8 The emergency and booking exceptions belong to other readings, so the next section takes up impeachment, and the sections after it follow the evidence a defective statement can produce.