Sounds like you want representation based on population percentage and not competence (not that Kagan’s a shining example of it).
It is obvious that competence and government are mutually exclusive. For government jobs, it is only fair to provide jobs based on representation.
I don’t think the garbage of all stripes and colors in Congress today in any way represent the best of any breed. E.g: Maxine Waters, Barney Frank, Charlie Rangel, Barbara Boxer.
It’s not impossible to have both. Of course, South Africa was pilloried for having so many minorities in charge of too many aspects of government and life in general.