What is the 'public safety exception' to Miranda?

The surviving suspect in the Boston Marathon bombing remains hospitalized. However, the FBI has begun to question the19-year-old, Dzhokhar Tsarnaev, without reading him his Miranda warnings.

The warnings come from a U.S. Supreme Court case, Miranda v. Arizona, 384 U.S. 436 (1966), in which the Court held that, to protect against involuntary self-incrimination, if prosecutors want to use statements at a trial that a defendant made in custody, the police must first have advised a suspect of his rights.

Federal officials said an elite interrogation team is questioning Tsarnaev. Questioning a suspect without reading him his Miranda rights is something allowed on a limited basis when the public may be in immediate danger, such as when bombs are planted and ready to go off.

The public safety exception to Miranda, comes from New York v. Quarles, 467 U.S. 649 (1984). In 1980, the state of New York charged Benjamin Quarles with possession of a weapon. He was a suspect in a rape, took refuge in a grocery store where he attempted to hide his gun.

When he was apprehended, before being mirandized, the police asked where he hid the gun.

The state court suppressed Quarles’ statement. Prosecutors argued to the U.S. Supreme Court that Miranda need not be strictly followed in situations "in which police officers ask questions reasonably prompted by a concern for the public safety."

The court ruled that there is an exception when the following framework exist—the presence of a public safety concern, limited questioning, and voluntariness.

The court made clear that only those questions necessary for the police "to secure their own safety or the safety of the public" were permitted under the public safety exception. The exception did not authorize police officers to compel a statement from a suspect.

Anthony D. Romero, the executive director of the American Civil Liberties Union, told the New York Times it would be acceptable for the FBI to ask Tsarnaev about “imminent” threats, like whether other bombs are hidden around Boston. But he said that for broader questioning, the F.B.I. must not “cut corners.”

“The public safety exception to Miranda should be a narrow and limited one, and it would be wholly inappropriate and unconstitutional to use it to create the case against the suspect,” Mr. Romero said. “The public safety exception would be meaningless if interrogations are given an open-ended time horizon.”

In 2010, the FBI issued a memorandum that encouraged agents to use a broad interpretation of the public safety exception. It said that the “magnitude and complexity” of the terrorist threat justified “a significantly more extensive public safety interrogation without Miranda warnings than would be permissible in an ordinary criminal case.”