The Truth About Miranda Rights Is They Don't Exist. Not How You Think, Anyway.
...his wings are clipped
his feet are tied
so he opens his throat to sing.
– "I Know Why the Caged Bird Sings" by Maya Angelou
Miranda v. Arizona has got to be THE most well-known piece of criminal case law in existence. "You have a right to remain silent. You have the right to consult with an attorney and to have an attorney present during questioning. If you can't afford an attorney, one will be appointed for you. Anything you say can and will..." etc. etc.
Your tea-totaling grandma knows it. 3rd-graders recite it while tying their friends up in licorice rope. Someone on TV is saying it RIGHT NOW. It's ubiquitous. It's also very misunderstood. The problem is probably the phrasing. You've heard of "Miranda Rights"? That makes it sound like you have a right to have the whole spiel read to you when you get arrested. You don't. People say "the cops didn't read me Miranda when they put the handcuffs on. Didn't they violate my rights?" No, they didn't. Not yet anyway.
You do have a right, under the 5th Amendment, not to be forced to testify against yourself in a criminal case. That's where Miranda comes from. To summarize wildly, back in the 50s and 60s, the Supreme Court thought it over and said, wait a minute, if the police can sit you down in a room, put the hot-light in your face, play the good-cop/bad-cop thing, lie to you, trick you, and maybe womp you on the head a few times to get you to confess, then trot out your confession in court, isn't that basically the same as forcing you to testify against yourself? So they decided no more coerced confessions allowed in court. Confessions have to be "knowing, voluntary, and intelligent."
Then the Arizona cops arrested and interrogated Mr. Ernesto Miranda, and to get around the "coerced confession" prohibition, they had Ernesto sign a form that said "I do hereby swear that I make this statement voluntarily and of my own free will, with no threats, coercion, or promises of immunity, and with full knowledge of my legal rights..." before his written confession. And they used it against him in court. Arizona courts gave this the A-OK, ("that's fine work, boys"), despite the fact that there was no indication Ernesto actually had "full knowledge" of his legal rights.
When it got to the Supreme Court, they said, wait, a "knowing, intelligent" confession means knowing your rights, but how can the court tell whether you actually knew your legal rights when you confessed, or whether you were just coerced into signing a statement saying you knew them. [To paraphrase Maya Angelou, we don't know why the caged bird sings, but it might be because he wasn't aware of his Constitutional right not to sing.]
So, they made this rule: any time the police have you in custody (IE, you're arrested), they have to remind you of your relevant Constitutional rights before questioning you or they can't use the things you say against you in court. It's just an easy, bright-line way to decide if a statement was probably coerced or probably voluntary. That's why Miranda is important, and that's why Miranda can, and does, still get criminal cases dismissed when the defendant makes incriminating statements to police. [Note: Most cops know to read the rights when they put the handcuffs on, so for criminal defense attorneys like me, Miranda is often a matter of trying to argue that you were actually "in custody" while being questioned before the formal arrest.]
But if the police don't want to question you, or they don't want to use your answers in court, they don't have to bother with Miranda. And sometimes they don't, which seems to be the case with that Boston bombing suspect. The police have plenty of evidence to use against that guy already. They really just want to find out what he knows, and they want that information more than a confession to use in court, so they decided to question him before reading him Miranda. Even though the media has made a really big deal out of it, the police are allowed to do that if they want. There is certainly lots of troubling and legally questionable police conduct going on out there in the world right now, but this isn't it.
Here's a bonus tidbit: Ever wonder what happens when the suspect says, "Actually I do want to have a lawyer present, and I can't afford one, so please appoint one to come advise me while you question me"? The answer is nothing happens. The police have to stop questioning that suspect, which is good, but they certainly will not rush out and find him a lawyer. That's because any lawyer who didn't FarmVille through the entire criminal procedure class (you know who you are, I sat right behind you) will promptly tell the suspect not to say a damn thing to the police. So it doesn't really behoove the police to have an army of state-funded lawyers waiting around the station to tell the arrestees to sit quietly and not answer questions. Of course you do actually have a right to a lawyer when the criminal case starts in court, but the whole "right-to-an-attorney-present-during-questioning" part of the Miranda warnings is silly. But here's the even stranger part: it's still important to invoke your right to counsel, because it's the best way to make questioning cease. Remaining silent is good, but the Supreme Court recently decided that the police are allowed to keep asking you questions while you remain silent, which might wear you down enough to talk, or might just really annoy you. But if you ask for a lawyer immediately, and you don't get one immediately (which you won't) then they have to stop with the questions. Weird, I know. But that's how it is.