Rich: That is the rhetorical figure known as “praeteritio.” Arthur Quinn,
in his 1982 book Figures of Speech, has this to say:
“If I were to declare any figure inherently disreputable (which, of course,
I will not), this would be the one. Neither will I mention that the only
American president who repeatedly used the praeteritio was also the only one
who had to resign. I will not mention it, despite its obvious relevance to
our present discussion, because anything that might be interpreted as a
political statement would be entirely inappropriate in a book like this.”