"Failing to Mirandize Dzhokhar Tsarnaev is not, in and of itself, a violation of his rights. "

From Atlantic Magazine:

Here's what much of the media have missed: regardless of whether the public-safety exception applies, the government is not, under the fairest reading of current Supreme Court law, constitutionally obligated to Mirandize Tsarnaev -- or any suspect for that matter. In the furor over the exception and the Republican senators' dubious stance, the media have conflated the issue of (a) whether or not Tsarnaev has a constitutional right to be Mirandized with the issues of (b) whether or not the public-safety exception was properly invoked and (c) whether or not Tsarnaev may be treated as an enemy combatant. 

The issues are distinct. Miranda establishes that statements made by a suspect in custody in response to interrogation are not admissible against the defendant in court unless the defendant has been properly Mirandized. Reading Miranda, one would be forgiven for thinking that law-enforcement agents are required to issue the familiar warnings regardless of whether they intend to use the statements in court. The Warren Court in Miranda stated that a suspect in custody "must bewarned prior to any questioning that he has the right to remain silent" and so on (emphasis added). 

But as with many of the constitutional rights recognized by the Warren Court in the field of criminal procedure, the Supreme Court has chipped away at theMiranda doctrine in subsequent cases. In recent years, pluralities for the Court have clarified that the privilege against self-incrimination (the Fifth Amendment right that Miranda protects) is not violated by mere questioning; rather the right is only violated when, unwarned -- to Mirandize is, in effect, to warn -- statements are admitted at trial. 

In the 2004 case United States v. Patane, a plurality for the Court stated that "deliberate failures to provide the suspect with the full panoply of warnings prescribed in Miranda" would not violate the suspect's constitutional rights or Miranda. It made the same point in the 2003 case Chavez v. Martinez. While these cases may be discounted as not holding the same precedential weight as majority decisions, they represent the best understanding of the state of the law today. 

Thus, failing to Mirandize Dzhokhar Tsarnaev is not, in and of itself, a violation of his rights. The authorities are not constitutionally obligated to Mirandize Tsarnaev anyway, so long as they do not intend to admit Tsarnaev's statements at trial. What the public-safety exception does -- if and only if a court determines that the exception was properly invoked -- is render Tsarnaev's unwarned statements admissible as evidence where they otherwise would not be. And even where the public-safety exception applies, the substantive rights that Miranda protects don't disappear: due process is in effect; any coerced statements remain inadmissible; and Tsarnaev may not be denied access to an attorney if he asks for one (though the federal circuit courts have held that questioning may continue for some period of time under the public-safety exception even after the request for counsel, and statements remain admissible). 

The authorities handling Tsarnaev's case might reasonably determine that, even if a court ultimately disapproves their invocation of the public-safety exception and suppresses whatever statements they seek to admit, the costs of Mirandizing Tsarnaev (his possible noncooperation) far outstrip the benefits of doing so (being able to use his incriminating statements in court). 

Specifically, in a case such as this one, where it seems likely both that the government will have overwhelming evidence to convict (without relying on any post-arrest statements) and that Tsarnaev may be in possession of valuable information that implicates national security, the rationale behind the government's choice emerges: Even if the public-safety exception is determined to have been wrongfully invoked, this would not threaten the government's case in a meaningful way. One may certainly contest whether the Court's shifting onMiranda is correct or whether the government's choice not to Mirandize Tsarnaev is desirable as a policy matter. Nor have the media been wrong to question the government's broad interpretation of the public-safety exception. But it is misleading to paint the decision not to Mirandize as trampling Tsarnaev's constitutional rights as an American citizen...

That the rule of law governs Tsarnaev's prosecution is paramount. To that end, thinking clearly about what the rule of law requires is just as crucial. [emphasis mine]

Most of the public discussion of Tsarnaev's Miranda warning and his Fifth and Sixth Amendment rights has been idiotic. Miranda warnings are an aid to prosecutors, not suspects, and are not constitutionally required, if prosecutors accept that they cannot use the suspect's statement at trial.

It's not really a difficult concept.

Why, then, was Tsarnaev Mirandized?