They better pick the independent Sanders or his voters will run from joe bite me.
Based on the notion that we all vote for Electors rather than actual nominees, I suppose the Dems could put Bernie up for nomination in a completely cynical manner. The young people flock in, maybe Bernie actually wins in Nov (I doubt it) and then around Dec 1 the DNC informs the Electors that they will be voting for Joe Biden when the Electoral College convenes.