A reader responds to my point from earlier that we would/could still have Miranda laws even if the Supreme Court had never imposed a Miranda rule:
Actually, we do have a Miranda law. I believe it is at 18 U.S.C. 3501, and it was passed ca. 1968-70 to supply a statutory standard for law enforcement personnel conducting interrogations. But the Court a couple years back ruled that observing it is no substitute for complying with the Miranda warnings, which therefore are the only reasonably certain way for DAs to ensure that information obtained from custodial interrogations will not be excluded. This despite language in the opinion itself stating that the warnings were only examples of what officers could say to inform the arrestee of his right to counsel. There is now even less incentive for states to legislate in this area, so the conduct of state law enforcement is now essentially driven, for better or worse, by nine unelected lawyers.
I made this argument in law school and asked why we even need state constitutions, given the incorporation doctrine and decisions like Miranda. Needless to say, I was called out as a fascist.