We're all painfully familiar with the "fruit of the poison tree" doctrine in the Fourth Amendment context: Evidence obtained by exploiting an unreasonable search or seizure is subject to suppression at trial. What judges and lawyers refer to as the "derivative evidence exclusionary rule" basically makes any evidence inadmissible if it was derived from an earlier violation of the defendant's constitutional rights. (Wong Sun v. U.S.)
But does that same consequence follow from the failure to follow the Miranda procedures? If you learn the whereabouts of contraband or evidence from a statement that doesn't comply with Miranda, must the contraband or evidence be suppressed as "poisonous fruit" of the inadmissible statement? Short answer: No.
Getting a Grip on Miranda
Ever since the 5-4 Miranda decision was issued in 1966, it has been the subject of considerable debate, litigation, and misunderstanding. More than a handful of judges, lawyers, and police officers mistakenly thought of Miranda as some sort of judicial rule about how police officers are required to conduct interrogations. But given the separation-of-powers structure of our Constitution, the judiciary has no inherent power to direct the functions of the executive branch (which includes law enforcement), as language from Supreme Court opinions has tried to make clear:
"Miranda's purpose was not promulgation of judicially preferred standards for police interrogation, a function we are quite powerless to perform." (Michigan v. Tucker)
"Nothing in the Constitution vests in us the authority to mandate a code of behavior for state officials...." (Moran v. Burbine)
"The Miranda rule is not a code of police conduct....It is not for this Court to impose its preferred police practices on law enforcement officials." (U.S. v. Patane)
Then what exactly is the Miranda rule? It's an admissibility rule for criminal trial judges. All Miranda ever said was that courts could not admit as evidence of guilt a statement obtained by custodial interrogation, unless the defendant had first been told of his rights and had agreed to waive them and talk. "Miranda conditioned the admissibility at trial of any custodial confession on warning a suspect of his rights." (Missouri v. Seibert) "Miranda itself made clear that its focus was the admissibility of statements." (U.S. v. Patane)
Although it is not unusual to see lower court opinions mistakenly describing a police officer's interrogation as "unlawful" or "unconstitutional" based on a finding that Miranda procedures were not followed, the Supreme Court has been careful to note that it is only the erroneous introduction of a statement in court that violates the Fifth Amendment-not the officer's non-coercive questioning of the suspect.
In Chavez v. Martinez, the Supreme Court ruled that because non-Mirandized questioning is not unlawful or unconstitutional, officers cannot be sued civilly for violating a suspect's Fifth Amendment rights on the basis of such questioning. The court recently reaffirmed this distinction in the Patane case:
"A mere failure to give Miranda warnings does not, by itself, violate a suspect's constitutional rights or even the Miranda rule. Police do not violate a suspect's constitutional rights (or the Miranda rule) by negligent or even deliberate failures to provide the suspect with the full panoply of warnings prescribed by Miranda. Police cannot violate the Self-Incrimination Clause by taking unwarned though voluntary statements."
In other words, although Miranda procedures must be followed in order to ensure the admissibility of custodial statements at trial, they "are not themselves rights protected by the Constitution." (Moran v. Burbine) Therefore, non-coercive questioning that merely fails to meet Miranda's admissibility requirements is not unconstitutional. Because evidence derived from statements obtained without valid Miranda warnings and waivers is not the result of any constitutional violation, the derivative evidence exclusionary rule does not apply.
The Patane Case
Colorado Springs (Colo.) Police and BATF agents were investigating Samuel Patane for violating a domestic violence restraining order and being a convicted felon in possession of a concealable firearm. After being taken into custody and without complete Miranda warnings (because Patane interrupted the officer who was trying to give him the warning), Patane told officers where he kept his Glock .40. The pistol was seized and used as evidence to convict him of the federal firearms offense. Patane appealed.