Here is my tin foil hat comment of the day.
I think Biden is in as a distraction for Trump to go after so it takes Trumps heat off the other candidates. Joe cannot be the one dems are rallying behind. He is so not even close to as far left as the others and he does not seem to be taking this seriously.
I cannot see dems making that mistake again, Trumps attacks are just to devastating and they, I would assume learned from last election.
Joe would be 80 when he took office if he won. I just cannot see it.
On plus side they have started turning on each other. AOC's pac backing Bernie and already coming after Biden in papers.
Either way I think this is going to be epic to watch.
Beyond that, any tactic that the Dems use to divert heat away from whoever ends up being their "Chosen One" is proving to be an increasingly dumb move. October surprises are especially damaging because the public doesn't have time to work through them emotionally. Protecting and deflecting early in the process just delays the inevitable, especially against a candidate who has already been through the fire to the point where he has become Teflon.
If they were intelligent, they would be pushing to make the Primary bloodbath happen early, give plenty of airtime to whatever grievances are unearthed, and let the court of public opinion decide who is worthy to take up the mantle in spite of their known flaws.
Since they're not intelligent, they're going to circle the wagons and try to contain the demons like they did with Clinton, using Trump and maybe a few carefully selected Democrat patsies as distractions.