In the early 1930s, the American Communist Party attracted support from a wide range of liberal and radical intellectuals, partly in response to domestic politics, and also in opposition to the growing power of fascism abroad. "The Long War," a social history of these intellectuals and their political institutions, tells the story of the rift that developed among the groups loosely organized under the umbrella of the Party--representing communist supporters of the People's Front and those who would become anti-Stalinists--and the evolution of that rift into a generational divide that would...