The famous case of Miranda v. Arizona—derived from the Fifth Amendment privilege against self-incrimination—requires that law enforcement officers advise arrested suspects of certain rights, including the option of saying nothing. ((1966) 384 U.S. 436.)
Officers must provide Miranda warnings whenever they interrogate someone who is in custody. “Interrogation” includes not only express questioning, but also any words or actions that police officers should know are reasonably likely to elicit an incriminating response. Being “in custody” describes a situation in which a reasonable person in the suspect’s shoes would not feel free to leave.
The corollary of Miranda warnings is that the prosecution cannot use a suspect’s silence as evidence of guilt in a court of law—otherwise the warnings would be meaningless. But, the law doesn’t require interrogating police officers to “Mirandize” someone who isn’t technically “in custody.” As a result, police officers routinely question suspects after carefully letting them know that they are not under arrest and are free to leave—that way, officers don’t have to provide Miranda warnings. Even in that situation, though, suspects’ silence was sacrosanct: Prosecutors couldn’t use it against them at a later trial. That is, until recently.
On June 17, 2013, in a closely-contested decision, the United States Supreme Court held that prosecutors can in fact point to an out-of-custody suspect’s silence in response to police questioning as evidence of guilt. (Salinas v. Texas, 12-246.) The only way to prevent the government from introducing evidence at trial of the suspect’s silence is to explicitly invoke the right to say nothing. In other words, without being warned by the police or advised by a lawyer, and without even the benefit of the familiar Miranda warnings (which might trigger a “I want to invoke my right to be silent!”), the interviewee must apparently say words to the effect of, “I’m not saying anything because I invoke my right to silence.”
In the case that led to this new rule, a police officer who was investigating a murder asked the suspect (and eventual defendant), who was not then in custody, a series of questions over the course of an hour. The officer did not Mirandize the suspect. The suspect answered the questions, but hesitated when the officer asked whether a ballistics test would prove that the shell casings at the crime scene matched the suspect’s gun. He fidgeted for a bit and didn’t answer the question; the officer then moved on to additional questions that the suspect answered. Prosecutors then charged the suspect with murder. At trial, they argued that his reaction to the officer’s shell-casing question suggested his guilt. The Court ruled that this argument by the prosecutors was proper because the defendant had not clearly indicated that he intended to assert his Fifth Amendment right when asked about the shell casings.
The 2013 decision was arguably a logical extention of a 2010 ruling. In the 2010 case, the Court ruled that a suspect who is in custody, who has received the Miranda warning, and who says nothing in response hasn’t invoked the right to silence. If he simply remains silent and doesn’t affirmatively indicate that he intends to claim that right, he hasn’t actually invoked it—if, after remaining silent for a period of time, he finally provides a statement, that statement is presumptively admissible. (Berghuis v. Thompkins, 560 U.S. 370 (2010).)
The new Supreme Court decision raises weighty questions, such as whether it’s reasonable to place the onus of asserting constitutional rights on everyday people, most of whom have never cracked the spine of a criminal procedure or constitutional law book. The more practical question is what, exactly, an out-of-custody person must say to inquisitive police officers in order to claim the right to silence. To be safe, they should make clear that they are invoking their Fifth Amendment right to silence and have nothing further to say. That way their subsequent failure to answer any questions cannot be mentioned at trial.