The paradigm of unilineal evolutionism was debunked for biology by Darwin himself, who imaged evolution as a tree with many branches rather than a straight ladder. The debunking of the cultural myth was largely begun Franz Boas (1858-1942), another American anthropologist who stressed the importance of particular histories of cultures and societies over their ranking on some grand, ethnocentric scheme.

And this idea is still alive and breathing. Rep. King's thinking is in a direct line of descent from Morgan, and Roosevelt. The maybe puzzling but definitely sad thing about this is that not only is King not alone, but somehow, with so little knowledge of human nature and history, he manages to maintain a high position in our government. One would have thought that the demythologized view of humans ought to have become dominant by now.
We need anthropology, its knowledge and perspective, more than ever.