What is the current state of the law in the context of the Miranda waiver?

More specifically, once a suspect has been warned of his or her rights pursuant to Miranda, the question to be asked regarding any subsequent statement is whether it was made under circumstances establishing a voluntary, knowing waiver of those rights -- a question calling for an examination of the state of mind of the person undergoing interrogation, rather than the state of mind of the interrogator. (Moran v. Burbine (1986) 475 U.S. 412, 421-422, 106 S.Ct. 1135, 1140-1141, 89 L.Ed.2d 410 [deliberate misconduct of the police, if unknown to the suspect, is irrelevant to the waiver inquiry -- police failure to inform suspect of attorney's telephone call regarding his representation has no bearing upon the validity of the suspect's waiver of the right to counsel].)