How we cite our quotes: (Section.Paragraph) or (Section.Subsection.Paragraph)
Quote #1
The constitutional issue we decide […] is the admissibility of statements obtained from a defendant questioned while in custody or otherwise deprived of his freedom of action in any significant way. (Opinion.I.1)
This is the core question Miranda v. Arizona was trying to answer. Does the right of non-self-incrimination apply in a situation where a suspect is in custody and can't leave? Up to this point, the right was acknowledged in court, but not during police questioning.
Quote #2
At the outset, if a person in custody is to be subjected to interrogation, he must first be informed in clear and unequivocal terms that he has the right to remain silent. For those unaware of the privilege, the warning is needed simply to make them aware of it […]. It is not just the subnormal or woefully ignorant who succumb to an interrogator's imprecations […]. (Opinion.III.3)
The main point here is that, informed or not, you don't have to be a total idiot to cave under pressure.
Quote #3
The defendant who does not ask for counsel is the very defendant who most needs counsel. (Opinion.III.10)
Warren is making a pretty sophisticated psychological statement here. If you don't know your right to an attorney, you're probably the kind of person who doesn't know your other rights as well. You're more vulnerable than the next guy in some way. You need the protection of the law even more. Pretty compassionate, we think.