The Southern Fault Line explores the under-appreciated division in the South between the oligarchic rule of plantation owners and industrialists on the one hand, and the more democratic mindset of the mountain-dwelling small farmers on the other. These two mindsets were in continual tension from the 1800s to the 1960s, when the adherents of the more democratic side of the struggle capitulated to the oligarchical side in response to the Civil Rights movement.

Bryan Jones draws from his own family's centuries-old history in the region to explore the rise and fall of the "two minds" of the South. Through a comparison of the experiences of a slaveholding line in his family with three non-slaveholding lines, Jones provides a rich history of the politics of both class and race in the region from the Founding era to the present.

Throughout, Jones shows how deep the political differences were between the two regions, with oligarchy characterizing the slaveholding region and a more democratic ethos shaping the non-slaveholding areas. Jones serves as the final observer, a white boy observing not only the demise of the Jim Crow South, but—in the wake of the Civil Rights movement—the demise of the mountain democratic South as well. Today, the vast majority of Southern whites regardless of class support an oligarchical Republican Party.