Sanders isn't "far-left" and the "centrist" relics aren't "mainstream" anymore if intra-party polls are to be believed.
The last primary debunked your point. No matter how much Bernie Bros proclaimed as the future of the party, key constituents such as woman of color are always going to determine the policies through their powerful voices. Right now the base is being attacked by the bros and I think the only solution that should've been Tom Perez position to begin with, was to never pandered to a bunch of racist, sexist upper-class white guys who will be voting Republican in ten years. If we had followed that advice we would've been in better shape regarding our current division that was caused by the sh**tstorm by Bernard and his gang of deplorables. No matter what comes out of these fraud polls, the base will backdrop any attempts to allow the far-left opposition into our party.
