Even if you believe the South is that separate from the rest of the country, you might still, if you look hard enough, detect tendrils of Southern influence that extend past the Mason-Dixon Line. Race provides the obvious example. The slave states developed an elaborate and distinctively American binary racial system, in which everybody across a wide range of European origins was put into one category, white, and everybody across a wide range of African origins (including those with more white forebears than black forebears) was put into another category, black. These tendentious categories have been nationalized for so long that they seem natural to nearly all Americans. They are Southern-originated, but not Southern. They powerfully determine where we live, how we speak, how we think of ourselves, whom we choose to marry. They are deeply embedded in law and politics, through the census, police records, electoral polling, and many other means.
A frequent companion of the idea of a simple distinction between black and white is the idea of a simple distinction between racists and non-racists. There can’t be anybody left who believes that racists exist only in the South, but there are plenty of people, especially white people, who believe that racism is another simple binary and that they dwell on the better side of it.
Nicholas Lemann, “The Price of Union”, The New Yorker (2 November 2015), 92.