Neither Harman nor Lieberman was ousted by progressives...
Again, the existence of one or two candidates being replaced by different ones in the primary process -- assuming you understand these correctly, which so far you haven't -- is
not equivalent to an organized, well-funded, national shadow party that actively tests
every candidate, and challenges
every one found wanting.
It amazes me that you can't see this. It does, however, shed some light on Republicans's inability to police Mitt Romney.