Good to see you again, by the way; for a while I was afraid I'd been a bit too much of a jerk in our first conversation and run you off for good. Sorry about that

At least to some degree; I do feel that if they want to parse things so finely cops should be required to make the need for an "unambiguous" assertion of the right to remain silent part of the Miranda rap.

You're right though; there's a mountain of documentation on coerced jailhouse confessions. Despite Miranda, and prior to this ruling. People are on death row because of them; people have been executed because of them. Perhaps the worst part is that judges and even juries regularly look the other way; if someone admits guilt most people will consider them guilty whatever duress was applied to obtain the confession. A good defense attorney may be able to prevent such a statements acceptance as evidence, but if not conviction is almost guaranteed.

This ruling does not create that real, grave and preexisting problem. If a cop decides to take you in the back room and work you over with a rubber hose until you confess, saying, "I'm exercising my right to remain silent" first won't stop him. What this ruling will do is prevent a criminal who lets something slip from invoking their right against self incrimination retroactively.