A progressive third party

With the realization that Sanders will probably not win the Democratic Party nomination, and that said establishment Party is corrupt beyond repair, there has been a spate of internet articles on what to do with the Sanders campaign machine. One option I hear frequently is to take all that momentum and organization and form a progressive third party, one that challenges both the establishment Democratic and Republican Parties. We've come to realize that the Democratic Party is too far gone to the dark side of corporate cronyism never to return to its own progressive roots. In the posts that follow in this thread I'll provide my jeremiad on this.