I came across a very interesting article today.
It relates to the Miranda decision and warning. Although this is American case law everybody knows about it, since it is the basis of the warning, on every cop show and movie, that the suspect has “the right to remain silent” etc.
This comes from a decision in 1966 that police must ensure a suspect understands his rights (not to incriminate himself) and waives them only “knowingly and intelligently.”
Now comes a case where a suspect was warned, and was then questioned for nearly three hours, during which time he said almost nothing. A detective then began asking the suspect about his religious beliefs: “Do you pray to God to forgive you for shooting that boy down?” The suspect said, “Yes,” but refused to make any further confession. The prosecution introduced the statement as evidence, and a jury convicted.
The case was appealed and went to the US Supreme Court.
Four justices held that allowing the statement turns Miranda upside down and that criminal suspects must now unambiguously invoke their right to remain silent—which, counterintuitively, requires them to speak.
However, five justices held that after giving a Miranda warning, police may interrogate a suspect who has neither invoked nor waived his rights.
So, I guess the right not to incriminate, in the US, is now opt-in only.