I don't think that the greatest danger to the Democratic Party is the GOP

[Hortensis]

149. Nevertheless, Cajunblazer is correct.

It's why the one powerful leftist party is dominated by liberals, rather than radicals. Radicals/extremists/fars are typically too rigid in their thinking and actions to grow into major power blocs. Facing enemies jointly helps them stay unified, but remove the exterior threat and they start fighting among themselves over relatively minor matters and usually break up instead of agreeing to work together.

As for political positions, that is a perfect case in point. The liberals' are extremely similar to Bernie's, just differing in time lines and methods, but a unwillingness to cooperate that results from excessive righteousness and total indifference to and contempt for other people's opinions requires of his followers absolute rejection of any compromise, no matter how small. All solutions must be Bernie's, and all who don't join him are regarded implacably as enemies to be defeated.

This is now how things get done in a Democracy, where coalitions must be built to create majorities. But the inevitable failure of the smaller radical groups to cooperate to achieve their goals will be blamed on liberal corruption (what else could it be?), never by a good look in the mirror for the answers.

Imo, Bernie's more radical followers are very fortunate that what they want is for the most part what liberals want, but by now I know most will never admit that to themselves, much less anyone else.