The Miranda warning is part of a preventive criminal procedure rule that law enforcement are required to administer to protect an individual who is in custody and subject to direct questioning or its functional equivalent from a violation of his or her Fifth Amendment right against compelled self-incrimination. In Miranda v. Arizona (1966), the Supreme Court held that the admission of an elicited incriminating statement by a suspect not informed of these rights violates the Fifth Amendment and the Sixth Amendment right to counsel, through the incorporation of these rights into state law. Thus, if law enforcement officials decline to offer a Miranda warning to an individual in their custody, they may interrogate that person and act upon the knowledge gained, but may not use that person's statements as evidence against him or her in a criminal trial.
The circumstances triggering the Miranda safeguards i.e. Miranda rights are "custody" and "interrogation". Custody means formal arrest or the deprivation of freedom to an extent associated with formal arrest. Interrogation means explicit questioning or actions that are reasonably likely to elicit an incriminating response. The Supreme Court did not specify the exact wording to use when informing a suspect of his/her rights. However, the Court did create a set of guidelines that must be followed. The ruling states:
...The person in custody must, prior to interrogation, be clearly informed that he/she has the right to remain silent, and that anything the person says will be used against that person in court; the person must be clearly informed that he/she has the right to consult with an attorney and to have that attorney present during questioning, and that, if he/she is indigent, an attorney will be provided at no cost to represent him/her.
In Berkemer v. McCarty (1984), the Supreme Court decided that a person subjected to custodial interrogation is entitled to the benefit of the procedural safeguards enunciated in Miranda, regardless of the nature or severity of the offense of which he is suspected or for which he was arrested.
As a result, American English developed the verb Mirandize, meaning "read the Miranda rights to" a suspect (when the suspect is arrested).
Notably, the Miranda rights do not have to be read in any particular order, and they do not have to precisely match the language of the Miranda case as long as they are adequately and fully conveyed.
In Berghuis v. Thompkins (2010), the Supreme Court held that unless a suspect expressly states that he or she is invoking this right, subsequent voluntary statements made to an officer can be used against them in court, and police can continue to interact with (or question) the alleged criminal.