Charles L. Hughes, author of Country Soul: Making Music and Making Race in the American South, weighs in on Ken Burns' new documentary Country Music as well as past and present manifestations of "the central racial paradox at the heart of country music." In the sound of the 1960s and 1970s, nothing symbolized the rift between black and white America better than the seemingly divided genres of country and soul. Yet the music emerged from the same songwriters, musicians, and producers in the recording studios of Memphis and Nashville, Tennessee, and Muscle Shoals, Alabama—what Charles...