Z0MG Races Are Natural Kinds!!!
It's really kind of interesting once you ditch the "social construction" stuff. So far as I can tell, what we end up with is a bunch of fuzzy, indistinct patterns of not-particularly-important similarities and differences that roughly correspond to roughly the idea of race that most ordinary people have. Of course white, black and Asian can be broken down into smaller clusters, but that doesn't matter much. And of course we've "drawn lines" differently for different purposes, but that doesn't matter either. Both of those facts are cited as evidence that race is "socially constructed"...but either those arguments are invalid or x is socially constructed is perfectly consistent with x is a natural kind.
But the most important point in this vicinity is the metatheoretical point that questions about the reality or unreality of races have to be settled on purely scientific (broadly construed) grounds. Questions about the impact of various answers on debates about racism can't be allowed into the discussion. And there's simply no doubt that the recent ascendance of social constructionism about race to orthodoxy was driven primarily by such moral/political considerations. It's possible--though unlikely--that nominalism about races will turn out to be right in the end. Nominalism (though not: social constructionism) about races is a respectable position. Though it's probably wrong. The dangerous position is the leftist position that allows scientific conclusions to be determined by political considerations. Neo-Lysenkoism is the essence of political correctness, IMO.