Nobody in the Dem race will stand up to Sanders. Because whether they agree with him or not, they're all spineless weasels. Obviously, some of them agree with Sanders extreme positions.
A principled Dem (a commodity extremely rare today) would tell him off. And maybe surge ahead. I'll bet there's millions of average Dems who believe, like James Carville, that the party has lurched off the left side of the political universe.
But now they're stuck with Bernie and the rest.
We'll see what Mayor Doomberg does. He's the last hope for a semi-sane Dem in the race, and he hasn't even announced yet.