One hundred fifty years after the start of the Civil War, a musical revolution continues to divide America: why are we still fighting over the song “Dixie?” Robbie Robertson tells Kurt Andersen about another revolution — going electric with Dylan. And Kurt asks a documentaryfilmmaker about the arrest of the artist Ai Weiwei. China’s most famous artist internationally, Ai has found clever, headline-grabbing ways to critique the Chinese regime, and now the government is striking back.