Country music, the century-old genre of nostalgia, tradition, and twang, has never been more in style. Last week, for the first time in the history of the Billboard Hot 100, the three most popular songs in America were country songs. One explanation for the milestone is that the genre’s artists and audiences are finally leaning into streaming: This year, country has experienced a 20 percent rise in listenership, a surge outpaced only by those of Latin music and K-pop. But this is a strange victory to celebrate—and not only because last week’s No. 1 song, Jason Aldean’s “Try That in a Small Town,” has proved to be a political flash point. The tracks breaking through right now each sound like something other than country. The genre always conveys some amount of underdog defiance, but lately, the music and the conversation around it have a distinct tinge of resentment. In “Try That in a Small Town,” Aldean, the 46-year-old Georgia hitmaker, salutes supposedly rural values (honor, neighborliness, gun ownership) by warning the listener that supposedly urban …