And also, trying to form a new party with fresh voices and faces would never work.  But since the incumbent has the advantage in their district and if they are performing the will of their constituents, that would be the oportune time.  Rather than running as an independent Like Bernie Sanders or Ralph Nader or Joe Lieberman.  Starting from scratch is one of the main reasons the Green Party has never taken off.  Big lib creds, but no representation/name recognition/ or bargaining power.

That's why a split might work,  Instant bargaining power/fund raising ability,  and instant votes.  But a large contigency of Representatives would need to switch in order for it to be effective.   But the Progressives could run in the Blue Dog districts against the democratic party to keep them honest or at least expose their blatant corporatism.