"Many heralded Zinn as an innovator of “history from below,” but that was not quite true. Zinn had a different take on American history. Grabar traces it back to his Old Left background, which informed his beliefs after he transitioned to the New Left. Although he always denied it, after serving in World War II he became a member of the Communist Party (CPUSA) and was active in its various front groups. But like many CPUSA members and fellow travelers, he had become disillusioned after the revelation of Stalin’s crimes and had left its ranks by the time the New Left and the civil rights movement came on the scene. He also felt the party had become too moderate and insufficiently militant for his own taste.
Zinn, still on the far Left but now politically homeless, saw hope in the 1960s college radicals whom, he wrote, “had no illusion about Reds.” They “have seen Stalinism unmasked…They have watched aggression, subversion and double-dealing engaged in by all sides, West as well as East, ‘free world’ as well as ‘Communist world.’” His position was that of moral equivalence, allowing him to be slightly critical of the Eastern bloc while saving most of his fire for the “imperialist” policies of the United States. In effect, his new interpretation of history amounted to an assault on the United States as the major enemy of the civilized world."