When David E. Lilienthal, chairman of the Atomic Energy Commission, lost his battle to stop the development of the hydrogen bomb in 1950, he used the term “steamroller” to illustrate the overwhelming forces which opposed him. Throughout his term as AEC chairman (1946-1950), Lilienthal fought the “steamroller” that came to represent not only the drive toward the hydrogen bomb but a militarization of American society in general. Beginning with his early skirmishes with General Leslie R. Groves, continuing with his successful campaign to keep the nation’s atomic arsenal in the custody of a civilian agency and concluding with his failed efforts in combating the H-bomb, Lilienthal persistently challenged militarization at every turn. But Lilienthal’s battles against militarization were not limited to his AEC days. Both before and after his AEC chairmanship he took stances which went against the grain of militarization. Historically, Lilienthal’s stringent and sustained opposition to the “steamroller” of militarization helped pave the way for the questioning of military technology during the counter-culture movement in the 1960s and 1970s. He remains one of the most notable but lest heralded individual examples of American anti-militarization in the twentieth-century.