If a police officer questions a suspect who is in custody without giving the suspect the Miranda warnings, nothing the suspect says can be used against the suspect at trial. The purpose of this "exclusionary rule" is to deter the police from violating the Miranda rule, which the U.S. Supreme Court has said is required by the Constitution (Dickerson v. U.S., U.S. Sup. Ct. 2000).
Exceptions to the Miranda Rule
In the years since the Miranda case was decided, several exceptions to the above rule have emerged from the courts. The exceptions assume that the only reason the statement is inadmissible is the Miranda violation and not other possible forms of police misconduct, such as physical coercion.
Impeaching a Witness and at Sentencing
If a defendant gives testimony at trial that conflicts with a statement made to the police, the prosecutor can offer a statement elicited in violation of Miranda to impeach (attack) the defendant’s credibility. (Kansas v. Ventris, U.S. Sup. Ct. 2009.) Similarly, rules in many jurisdictions allow prosecutors to offer statements obtained in violation of Miranda against defendants in sentencing hearings. (U.S. v. Nichols, 4th Cir., 2006.) For example, assume that in an improperly obtained statement, a defendant admits to the police that he was armed with a weapon when he committed a crime. The defendant’s confession may not be admissible at trial to prove the defendant’s guilt, but the prosecutor may offer it into evidence during sentencing to try to obtain a harsher sentence.
Using unMirandized Statements to Gather Other Evidence: “Fruits of the Poisonous Tree”
Normally, the government cannot use the “fruits” of statements taken in violation of Miranda. If police officers learn about evidence by taking a defendant’s statement in violation of Miranda, that evidence is normally inadmissible against the defendant. But there are some common exceptions to this exclusionary rule:
- Public safety. In dangerous situations, the “public safety” exception allows police officers to question suspects about weapons without giving a Miranda warning. If the interrogation leads the police to a weapon, it can be used against the suspect at trial. (N.Y. v. Quarles, U.S. Sup. Ct. 1984.)
- Tangible evidence. Dangerous situation or not, any tangible evidence (such as a threatening note or the loot from a robbery) that the police learn about through questioning that violates Miranda can generally be used against a suspect in court. (U.S. v. Patane, U.S. Sup. Ct. 2004.)
- Witness. If a statement taken in violation of Miranda leads the police to another witness, that witness can testify against a suspect at trial. (Michigan v. Tucker, U.S. Sup. Ct. 1974.)
- “Inevitable discovery.” If the police would have eventually found tangible evidence on their own, the evidence can be used against a suspect at trial even if the police actually found out about it during questioning that violates Miranda.
The Broad Reach of the Miranda Exceptions
These exceptions to the Miranda rule give the police a real incentive to violate the rule. Moreover, they mean that suspects have to protect themselves. Suspects who think that what they say can’t be used against them at trial because they weren’t given Miranda warnings need to understand that these “fruits” of their improperly obtained statements may well be admissible in evidence.