To be fair, there's a good chance this leak was the GOP's dirty work. They're just as frightened over the prospect of Trump winning as the Democrats are.
Personally, I think the GOP-e (prodded by the Bushes and/or Romney) actually threw this poop at the wall, and - I would imagine to their intense frustration - Trump got a two-fer: it opened the door for him to go after Hillary, AND it revealed the more pathetic NeverTrump (perhaps now to be known as "NeverTrust") weenies.
Mr. niteowl77