A candidacy the inner party corporatists cannot control, vs one that cannot win.
Bernie will bring out the vote. Biden would discourage new voters from voting. He would be poison as the candidate. The inner party functionaries want Joe, but if they persist, they get four more, little else. Perhaps they'd rather that, than losing a major bit of their power within the Party - a power to mess things up royally when they don't like popular choice - which their actions suggest to be the case, 2016, and now.
BOTTOM LINE:
The image tells the story, while the words of others do injustice to truth.
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Biden is good at lessening promising avenues of CHANGE. Few do that as well. Joe did it top notch, while in the Senate and within both Obama terms. Not that Obama wanted CHANGE, beyond it having sloganeering value. He followed traditional DC masters, and has done well for his family since leaving office. Biden saw, and wants. Bernie? It is not about him, it is about us. For us.
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Either run Bernie, or put a "FOR SALE" sign on the entire Democratic Party apparatus as corrupt beyond help.
Beyond HOPE.
Things seem poised for an inner party cramdown error, again. Hopefully the people, by voting, intervene.