It may well be true that Biden himself inspires only mild levels of enthusiasm among voters when pollsters ask them about it in the abstract. But in reality, when faced with a choice between Biden and Sanders, voters have showed up in states across the country to express their support for the former vice president. That’s a very good sign that they will do the same when his opponent is the far more widely loathed Republican in the White House. It’s also important to keep in mind that Trump is benefitting at the moment from a rally-round-the-president effect from the coronavirus crisis. That bump, along with a few mildly scary head-to-head polls, is unlikely to persist through the next seven months. (And even now Biden still leads Trump in aggregate head-to-head polling by 5.8 points.)
As for the possibility of the Biden candidacy being consumed by a sexual scandal, it will depend on whether the alleged victim can offer any kind of corroboration to back up her claims about an event 27 years in the past — and if anyone else comes forward with similar accusations. If the latter happens, Biden could be in trouble. But if not, a single unsubstantiated claim from nearly three decades ago is unlikely to wound a candidate running against a flagrant misogynist who brags about his own serial assaults on women.
Biden might not be any Democrat’s idea of a perfect candidate. But more factions of the fractious party like him than anyone else around. That makes Biden something very close to a generic Democrat with the broadest possible appeal — which could make him a fearsome opponent to take on a president as polarizing and deeply disliked as Donald Trump.