Joe Biden clearly thinks he would have beaten Trump if he had run and received the nomination in 2016. He is quite possibly right. The question for the day is, how would his candidacy have impacted the 2016 primaries? Did he have a realistic path to the nomination?
Your initial reaction probably is to think that he would have split the realo vote with Clinton and thus helped Sanders win the nomination. Surveys taken around the primaries, however, indicated that a large percentage of Sanders voters were actually well to the right of their preferred candidate, who was chosen for reasons of identity, not ideology. As a result, it is much more likely that Biden would have taken votes from Sanders than Clinton.
My counterfactual? Clinton had the establishment vote locked up, and had strong support from women and minorities. The final outcome would have been Clinton at 50 percent and Biden and Sanders at 25 percent. This would have destroyed anyone’s illusions about the “revolution” for all time. But, of course, it didn’t happen, and the illusion persists.