The basic logic of graduated deterrence worked fairly well against the Soviet Union, as each level of aggression was to be deterred by a matching response. But this logic has now been undermined vis-à-vis future rogue state chemical and biological attacks by the spread of dual-use technologies that can be diverted to weapons, and by decisions of the United States and other democracies to forego possession of chemical or biological weapons. This article identifies some of the serious difficulties of alternative approaches to deterring chemical or biological attacks, ranging from nuclear escalation to a reliance on supposed American advantages in conventional weapons. Lumping chemical and biological weapons together with nuclear weapons into a new category of "weapons of mass destruction" is a very imperfect solution.