I do not want my position on this misunderstood; I am not for giving the Feds any leeway as far as detainment and prosecution go.
As far as I know, Bomber #2 could have clammed up right from the start and insisted on a lawyer; he would have been well within his rights to do so and that has to be respected.
Unless I'm mistaken, roughly, the "Miranda" ruling resulted in a suspect self-incriminating because he either didn't know his rights or was bullied into disclosing that which was used in trial against him. That cannot be the case now; the law is, and the FBI knows, that anything self-revealed cannot be used against the accused pre-Mirandizing OR if the accused demands a lawyer and refuses to speak to them.
The Fifth Amendment reads, in part:
"No person shall be held to answer for a capital, or otherwise *infamous crime*, unless on a presentment or indictment of a Grand Jury, except in cases arising ..... when in actual service in time of War or public danger ....... nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property without due process of law ....."
I believe the "national security" exception/issue was carved out of the "public danger" part of the Amendment.
As far as treating Bomber #2 as an enemy combatant, for all the calls to do so from Senators and those who should damn well know better, Congress itself, in 2002, passed a law whereby ties to AQ or another terrorist group must be present for the classification to legally apply. Which is what the FBI was trying to ascertain, I'm guessing, before the dhimmi judge showed up with her phalanx of terrorist-defending lawyers.