In the middle of 1950s, the Soviet Union acquired the ability to attack the continental United States. In the face of being exposed to an attack by the Soviet Union, how to limit the damage of the United States, especially the civil defense program, became a serious issue. And the growing expectation of the emergence of ICBMs made it more serious. The Gaither Committee began its study in the summer of 1957. At first, its purpose was to review the civil defense program previously submitted to President Eisenhower. But the committee enlarged its area of inquiry and made an across-the-board report called the Gaither Report. It pointed out that civil defense planning would not be enough for the national security of the United States and, more importantly, it also pointed out the vulnerability of SAC to a surprise attak by the Soviet Union. To assure the security of the United States, it stressed strengthening deterrence through the build-up of strategic forces. Secondly, it suggested that the aquisition of an invulnerable second strike capability was necessary. And thirdly, it requested a huge, financial expenditure to realize these measures. At the time when the American nuclear strategy was in transition, reflecting the opening of an ICBM era, the Gaither Report showed the direction to go-the orthodox direction in American nuclear strategy, which accelerated the nuclear arms race between the United States and the Soviet Union. The contents of its recommendations were implemented by subsequent adminstrations and were eventually realized. In this sence, the Gaither Report is the guidepost for American nuclear strategy in a time of change.