The contemporary strategic era, dominated by ballistic missiles, has appeared to possess a curious kind of stability. Despite its uncertainties and dangers, two factors were apparently beyond dispute. On the one hand, neither the Soviet Union nor the United States could eliminate the other's missile forces in a first strike or effectively defend against a retaliatory missile strike. The offense seemed to have made a quantum jump against the defense: the old pattern of oscillation between defensive and offensive superiority had apparently been superseded by a period in which, for the foreseeable future, defense would be definitely inferior and incapable of matching offensive gains. On the other hand, missiles were so expensive and required so much technical sophistication that very few countries could either afford them or build them. The vexing problem of nuclear proliferation thus appeared in a new light. Even if a state could develop a nuclear bomb, it was assumed that it could not be a truly "effective" member of the nuclear club unless it also developed a missile to deliver it somewhere. The double task of building a bomb and a sophisticated delivery system inevitably seemed so difficult that the problem of preventing a thoroughly destabilizing nuclear proliferation appeared relatively simple. At worst, the process could be "managed."
