As for your post #13, I'll try to break it down as I happen to disagree with your assessment.
Now, let's talk about Kamala Harris. She is from a solid blue state.
Biden was from a solid blue state when Obama chose him. Also, research indicates that VP candidates state of residence generally has no effect on how a presidential candidate performs in that state.
She barely garnered 5% of the black vote during her entire primary campaign.
There were several factors at play. Large primary field, Biden was the first black POTUS's VP, etc. Harris had the highest # of CBC endorsements prior to her dropping out (yes, I know that's not "regular" voters, but among her peers). BTW, Booker or Patrick had even less support with voters.
She used incredibly bad judgment in trying to derail Joe Biden's campaign by playing the race card several times. Unless you were living under a rock, everyone knows those attempts backfired spectacularly on her. I believe that was what ultimately set her on the path to withdrawing from the race.
If you recall prior to that debate, Biden was recounting having worked with segregationists. He brought it into the conversation and she expressed how she felt as a little girl. That isn't "playing the race card" it's illuminating her life's experience. Also, Biden doesn't hold a grudge about it, he understands politics isn't beanbag.
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Further, it is insulting to say she would not bring anything to Biden's campaign. Harris has both executive and legislative experience. She won statewide in the nations most populous state 3 times. She has also worked tirelessly for down-ticket races across the country and advocates for marginalized voices across the spectrum.
Harris has the 2nd highest lifetime rating of being a progressive democrat (higher than both Sanders and Warren) -->
https://progressivepunch.org/scores.htm?house=senate
She also happens to be representative of the backbone of the democratic party -- black women, and representation matters. YMMV