If Biden were the likely nominee, the GOP is an existential threat, so I'd vote for him, but let's not pretend it wouldn't be an alienating pick.
Alienated centrists will do their duty, too.
And yes, there are some leftist swing votes who wouldn't have voted Biden. But centrist strategy includes seeking swing votes, too—just different swing votes.
I think the expectation is alienated centrists will do what alienated leftists do.
I have more hope in Sanders' plan coming to fruition than Biden's. People are struggling and desperate.
But what do I know, I'm never lied my country into war then received a well-paid job giving my opinions.
There was always going to be a group out of this who would have to deal w/their alienation. Therefore the nominee was always going to be a gamble.
But I can know this would be the same "gamble" if it was Warren surging. People used to being attended have to deal with not that, and they don't like it. I hope they get over it. I trust most will.