To understand the fortunes of American communism during its heyday in the 1930s and forties requires a healthy taste for irony. On the one hand, the apostles of Lenin and Stalin yoked themselves to one of the bloodiest, most repressive regimes in history and the first one whose dictatorial nature mocked its own vision of a world run by working people. Yet the Communist party had a striking influence on American culture, although seldom in its own name. The influence of Popular Front culture endured long after the party had been banished to the crumbling margins of American politics. The number of renowned writers, filmmakers, entertainers, and artists who had traveled with the Communists during its heyday was quite remarkable, given the party’s modest size and electoral inconsequence. Party members wrote “Ballad for Americans,” “Strange Fruit,” “This Land Is Your Land,” Native Son, The Little Foxes, and Mr. Smith Goes to Washington. Artists who, while not members, had spent many evenings in the party’s milieu, created Citizen Kane, Death of a Salesman, “Fanfare for the Common Man,” For Whom the Bell Tolls, Yertle the Turtle, Invisible Man, and wrote the screenplay for Casablanca. Novelists in or close to the party had nine books at or near the top of the best-seller list from 1929 to 1945.

That we still view the Depression largely through images created by such figures suggests that the Left was more influential working through aesthetics than organization. Radicals achieved their only lasting triumphs during the years of the 1930s and forties by advancing a new common sense about larger social and moral questions: Who were the people? How did they want the nation to change? What did a commitment to equal rights require? As a young, left-wing critic observed in 1942, “It was the depression of the mind that from the first gave significance to the depression of society, for the impact of the crisis on culture was far more violent than its transformation of the social order.”

This new spirit brashly claimed the Left’s desire and need to claim America—its polyglot culture, its history, its productive might—for an expanded definition of the common people. Popular Front artists took up subjects and themes that went beyond the limits of New Deal politics. They hailed the progressive impulses of folk and blues musicians, fertilized a campaign against segregationist laws and practices that would flower fully a generation later, and made films that paid tribute to populist mass movements.

The very creation of a marketable genre known as “folk music” was due almost entirely to the Popular Front. From his office at the Works Progress Administration, Charles Seeger (father of Pete) wrote, “The folk music of America [has] embodied … the tonal and rhythmic expression of untold millions of rural and even urban Americans … the American people at large has had plenty to say and ability to say it.”