"They need the left to win" Interesting - that.......

Given that it seems that the left is the group most likely to bail I would submit that they are a smaller group, in the Democratic party, than the middle, etc. I think you are referring, as the left, those who support Bernie. I doubt others will bail and those who refuse all if Bernie is not anointed. They have already proven they will either not vote at all or vote for Trump in such circumstances.

My own attitude that, if that happens then screw 'em.

I just want Trump gone - all the rest of that political stuff is actually of no real interest to me.