Who do you want to replace Biden?
I know I'm not going to get who I want. I'd run Bernie or AOC if it was about my personal preference. But that's not what this is. I think Biden is one of the worst people possible to take on Trump.
I think Minnesota Governor Tim Walz would be a great choice. Moderate profile but significant progressive accomplishments that have made lives better. I'd be worried about the "Kamala pushed aside" narrative, though. Pissing off black women who watch MSNBC is one off the dumbest things the Dems could do. Ultimately, if I had the power to decide, I would invest in a team of psychiatrists to help her with this laughing issue and I would run Kamala Harris.
If Biden had stepped aside and allowed a primary, I think there are other minority candidates who could have earned the nomination. I can't think of anyone else who is ready to be anointed as the nominee, though. I think it has to be Kamala.