The Miranda warning comes from the Supreme Court case Miranda v. Arizona. The Court wanted to ensure that people who are accused of crimes and are in police custody understood that they had a right to remain silent and against self-incrimination under the 5th amendment and that they had a right to a lawyer under the sixth amendment. This is the reading we hear in nearly all police shows and movies, it goes something like this:
Once a person is apprised of their rights, they can make the decision to whether or not to participate in the interrogation. If, police do not read a person the Miranda warning, the statement cannot be used against the person in court. However, the prosecutor can try to introduce the person’s statement in court and it will be up to criminal court judge on the case to decide if the statements can be used in court against the person.
Police must show that the accused voluntarily, knowingly, and intelligently waived his or her rights by an actual expressed statement. Silence by the accused after the warnings are read does not constitute waiver of rights.