He's a historian with a great eye on history. My theory is he first of all just wanted to go down in history on the list of British PMs, have his painting on the wall of nr 10 (or wherever PM portraits hang). His name is now...
Now he's already guaranteed his name has gone down in history, he has to deal with the promises ...
He doesn't back down - that would make him look like...
So he pushes an even harder Brexit that he KNOWS will have to be stopped by parliament and the EU would never agree ...
So, for him, it doesn't even matter if he is forced to have another election. And it doesn't matter even if he loses the election and is one of the shortest PMs in history. He ...
Every scenario is a win-win for him, in his mind.
Unless, f course, he backs down.
Or- interestingly - unless a no-deal Brexit actually happens and he becomes the PM responsible for an economic ...
This explains why Johnson is giving conditions for Brexit he knows will never be accepted.
He wants to be stopped.