You like the quote of Elena Karan (Kagan)?
Care to explain the best and worst thing? Not listed among her top quotes with good reason, gobbldygook.
https://www.inspiringquotes.us/author/9407-elena-kagan
It's not gobbledygook (which is how that is spelled, btw).
The reason it's the best thing is it was our country trying to lift itself beyond its past, beyond its biases.
The reason it's the worst thing is that we needed (and still need, but do not have) those elements to counter the biases that remain in our country, despite efforts like that.
It is describing the paradox of America - our potential and our failures to achieve that potential.
I am sorry that the tension between those two concepts was lost on you and I sincerely hope that my words help you to see/feel it more easily.