A Nat friend told me he knew at the time that the once in a generation/lifetime would come back to haunt them, and that it's a hard argument to counter.

He is so right.  You can't just make stuff up to get folk to vote a certain way, then expect everyone to act like it never happened.

If The Big Lie hadn't been told then I reckon the 11pt margin would actually have been 15 or so.