To buttress what @fixxer stated: i do think it should be allowed for states to have horrible rules and laws (anti-miscegenation, anti-gay, anti-white, etc). People have, and will continue, to vote with their feet. More poignantly, companies will vote with their foot print. If a majority of people in Arkansas want to establish the state as a White Majority Zone, democracy dictates that it must be so. Ditto for any other region or color.

Maybe? I wouldn't want to live in those states and I think that would be pervasive. Ultimately, economics would drive progress.

All conjecture. If only social science was a real science and we could do independent trials.