There is no plausible or foreseeable nonnuclear threat faced by the United States either in respect to its homeland or abroad which could threaten U.S. supreme national interests and which could not be countered by conventional means. In contrast many states of the world face severe threats to their very existence. In fact, under such a doctrine, possession of nuclear weapons is much easier to justify for such states than it is for the United States. The deterrent value of nuclear weapons against threatened or actual use of chemical and biological weapons continues to surface. I consider aggregation of nuclear, chemical, and biological weapons into a single WMD category to be counterproductive.
Chemical weapons are by no means weapons of mass destruction.
In fact the military effectiveness of chemical weapons for a given weight of delivered munitions may be less against prepared enemy troops than that of conventional explosives. They remain principally weapons of terror meant to intimidate civilian populations. In contrast nuclear weapons can increase the destructive energy delivered by a given weight of munitions by well above a factor of 1 million relative to conventional explosives. In principle biological weapons may produce lethal results comparable to nuclear weapons per unit weight of delivered munitions against civilian populations, but happily the military effectiveness of biological weapons remains to be established. Biological weapons are not effective battlefield weapons.