i think it was mostly just an attempt to staunch the bleeding. they knew biden would not only get crushed; he would get crushed so badly that he would give trump a supermajority in the senate. so they pushed biden out, hoping to do a mini-primary. but biden decided to poison-pill the traitors and immediately backed kamala, who he knew was a d-tier political talent. once he gave that endorsement, the dems were locked in. if they went for anyone else at that point, it would alienate women or black people. so everyone immediately fell in line behind kamala; but they had no illusions that she was any good. sure, they pretended. but c'mon. everyone knew that she sucked.
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