Trump hasn't been living in retirement, he hasn't come from nowhere, he's spent much of his life surrounded by recording devices. I'm less surprised by the Bobby Bush tape than I am that we haven't been inundated with such things. It's never been a secret that Trump is that kind of guy.
His party's establishment didn't want him. They knew that sooner or later something like this would emerge. I'm thinking that the Republican grandees who are disowning him now must be doing it with a mixture of despair and relief. They were waiting for this to happen and now the waiting is over.
Trump has said he won't withdraw- but when politicians say they won't do a thing it's usually because they're on the brink of doing it. He's going to be under enormous pressure right now. If his name is still on the ballot in 30 days time it'll be a testimony to the quite extraordinary thickness of his hide.