Some instances of appellation after separation are honorary in nature. It is, I understand from somewhere in my dim dark past, perfectly acceptable to refer to former/retired judges as Judge so-and-so, just as it is apparently acceptable to call former coaches by the title "coach." Why? I have no idea.
As far as political figures, though, to the best of my knowledge the only such title that it's acceptable to use is Mr. President for former presidents of the US. I suspect it's in recognition of the office, not the person.
