Can Sanders Run Against Clinton without Running against Obama?

Sanders has kept his criticisms of the Obama administration pretty muted for the most part. But to the extent that he starts critiquing Clinton's proposals and policies, many which of which revise and extend, but don't erase, Obama's approaches, doesn't he basically need to argue that Obama got it wrong or that it's time to supersede those approaches entirely?

Hilary is running to be the steward and guardian of recent Democratic gains, who will move them forward incrementally. Sanders is running to be a transcendent figure, who starts a revolution, wipes the slate clean, and allows the party to just route the plutocratic opposition.

That seems a pretty hard sell over the long term in the democratic primaries. In the early states like Iowa and New Hampshire, where idealism and infatuation play a larger roll and just a pretty arrow slice of the democratic coalition is involved, and where realism almost never plays a role, he can get away with this maybe.

But it seems kind of a strange long term strategy in the end.

I think Sanders is really running to remake the entire democratic party from bottom up in his own image. Very seriously doubt he can pull that off. He wants the party to really and truly become a party modeled after the democratic socialist parties of Europe or at least the social democrats of Europe.