Your Constitutional Rights
The Miranda warning is a verbal warning that all police officers must give a suspect before s/he is about to be taken into custody, and applies the whole time s/he is in custody. Custody means a formal arrest or the deprivation of freedom where a reasonable person does not feel like s/he can leave. It is the result of the famous 1996 Supreme Court case of Miranda v. Arizona, and has become part of established criminal procedure law to ensure that every American’s Fifth Amendment right against compelled self-incrimination is not violated.
In that specific case, Defendant Ernesto Miranda was arrested by the Phoenix Police Department on March 13, 1963, on suspect of kidnapping and rape. After two hours of police interrogation, he signed a confession, and was subsequently convicted. Miranda’s lawyer appealed his conviction on the grounds his confession was never fully voluntary and should have been excluded from his prosecution. The Supreme Court held that due to the coercive nature of police interrogations, no confession nor statement could be admissible in court under the Fifth and Sixth Amendment right to a lawyer, unless a suspect knowingly and voluntarily waives his or her rights.