It's taken for granted by political insiders that if Hillary is forced to drop out, that Biden is waiting in the wings to replace her. That may be the case, but it could damage the Democrats even more.
Biden never got into the race and the Democratic primaries turned out to be a hard fought battle between Hillary and Bernie Sanders. And the scars of that war are still fresh. There is a sizable amount of support for Bernie Sanders to replace Hillary. Far less for Biden.
The latest Rasmussen Reports national telephone and online survey finds that 48% of Likely Democratic Voters believe Vermont Senator Bernie Sanders, Clinton’s primary rival, should be their party’s nominee if health issues forced her out of the race. Twenty-two percent (22%) say Vice President Joe Biden should be the nominee, while only 14% opt for Virginia Senator Tim Kaine, the current Democratic vice presidential candidate.
That's not surprising. Who cares about Kaine anyway. But Biden's numbers are rather weak. There is a sizable base for Bernie. That means that trying to shove in Biden would set off another civil war.
Bernie Sanders has better likability ratings, but he would drive away what's left of the moderates in the ranks of the Democratic base. And so trading Hillary for Bernie may be trading one electability problem for another.