They can play spoiler, elect hard-right Republicans, and drive the Democratic party towards the center in pursuit of swing votes...or they can run in Democratic primaries, stop playing spoiler, and move the Democratic party leftward.

Why they are so content to be option 1 is a mystery to me.  I guess it is the whole self-righteous martyr complex.  They're happy to be spoilers while maintaining ideological purity, while us in the progressive Democratic community grudgingly work our asses off for conservative Dems like Sen. Ben Nelson and Rep. Jim Matheson because they are our best hopes in blood-red districts and states...and they ARE better than the alternative.