"I take Joe's point aboiut the passage of time and I am not altogether sure about the wisdom of prosecuting those who are obviously very old and infirm (ala Demjanjuk in unrelated matter)."

I've never understood this argument. It implies that if you commit horrible human rights abuses, and can evade justice for long enough, you don't have to worry (and far too many such criminals do seem to evade justice). The argument implies that horrible and bestial crimes have a sort of 'sell-by-date' and once the criminal passes a certain 'magic age' they don't have to worry about being brought to book any more.

There's a chance that the prospect of being prosecuted in infirm old age could even act as a deterrent. In my opinion only the death of a human rights abuser should free them from the fear of prosecution.