How do we make sense of the fact that America’s most progressive cities, the ones that cherish diversity, are losing African Americans? And that the most conservative places are doing the opposite? Between 2000 and 2010, cities like Austin, Chicago, Washington D.C., San Francisco—places that vote majority Democrat, consider themselves socially and culturally progressive, and boast racial diversity—all lost unprecedented numbers of African Americans. San Francisco, for instance, saw a staggering 20.4 percent loss in its African American population between 2000 and 2010. Chicago and Washington D.C. also experienced double-digit losses. During that same decade, the only three major cities...