A losing argument among Dems. Hillary is the nominee unless the FBI recommends an indictment. She has always been the presumptive nominee. This Potemkin primary was just a vehicle to keep some of the focus on the Dems during the primary season.
The Dems will not nominate an independent, socialist (age 74) to be their nominee. Even if Hillary were to be indicted, Bernie won't be the nominee. They will dust off Biden and insert him in the race. That may have been the plan from the beginning hence Biden's higher profile lately.
I agree, Biden has been the main back up for some time now. I also remember Elisabeth Warren’s meeting with Biden around the same time Biden was claiming he wasn’t running. My guess is Warren would run with him to get the progressives excited.
If the Rats simply ignore Bernie's voters by inserting Biden in when Hill washes out (for whatever reason), Bernie's voters may indeed turn out for Trump to pay the Rats back.