Less than a year after the bombing of Hiroshima, Congress passed the McMahon Bill for the domestic control of atomic energy, otherwise known as the Atomic Energy Act of 1946. In this article, I reconstruct the controversy surrounding the passage of this legislation, and specifically the effort by proponents of the McMahon Bill to focus the controversy on what role, if any, the military should have in decisions related to atomic policy. Throughout the controversy, proponents of the McMahon Bill evoked the threat of the garrison state to stress the dangers of a politically powerful military and presented the public with a choice between a slow-motion coup d’état led by experts in violence and a commission of experts appointed by the president. In so doing, they transformed what began as a controversy over how to control atomic energy in a manner consistent with the best traditions of representative democracy into a controversy over who was best qualified to manage atomic energy on the public’s behalf. This transformation allowed them to herald the passage of the McMahon Bill as a victory for democracy even as they acknowledged it as a historic break from tradition. The controversy over domestic control must be acknowledged as a key moment in the evolution of Cold War rhetoric—a rhetoric in which national security would trump issues of public participation and in which the public’s exclusion from the policy process could be taken for granted.