The question anyone suggesting replacing Biden needs to answer is: Who?
Pretty much the entire electorate needs to know who the person is. They need to be somewhat popular. They need no real scandals.
That's just the bare minimum to complete with Biden. Then you have to answer: can they be popular enough, or overcome Biden's weaknesses enough to overcome incumbency bias?
That's not easy to answer but if the answer isn't a resounding Yes, then replacing him is a mistake.
And the candidate has to be popular enough that Biden is willing to stand down and support them. Because he has pledged delegates and several primaries already.
Overall I think this would be a mistake. There just aren't any good alternatives. And one bad debate isn't a scandal. This is letting the Fox News machine dictate how we think about Biden. Which is always a mistake.
Preemptive: take what I'm saying with a heavy grain of salt, obviously and as always.
The true liberals will vote Dem no matter what - Kamala Harris, Pete Buttigieg, hell this group would vote for Pete Davidson at this point!
The true conservatives... same, mostly. Unless the liberals advanced someone like Liz Cheney or Mitt Romney, who may be able to chip into that? (This is when we finally stop pretending that liberals have any options in this race, midway between neoliberalism and outright fascism.) Bc just like Dem != liberal, but differently, Repub != Trump-er.
There are probably like 5-100 people in the middle somewhere, but bc they live in swing states somehow determine the course of the entire nation. Would this be a time to be risky and advance AOC - as a young, passionate, genuine person, since the votes of neither liberals nor conservatives are likely to be affected either way? Except the old money probably worries too much that they could not control her, whereas both Trump and Biden have been vetted in this regard.