Since the mid-1980s, the United States and the Soviet Union, later Russia, have achieved substantial reductions in their nuclear forces. The primary factor in these reductions has undoubtedly been the end of the Cold War, by eliminating the perception on each side that its highest security concern was deterring a nuclear strike by the other. Nevertheless, the reductions negotiated to date still leave very large nuclear forces. Moreover, these forces are potentially unbalanced.
START II is projected to leave Russia with some 1600 nuclear warheads by 2010, while the United States would retain an "upload" capability of up to 7000 warheads (von Hippel, 1997, p. 11). This is part due to the technical feasibility of placing warheads back aboard MIRV missiles whose warhead numbers have been reduced under the treaty, and even more to the ability to re-configure B-1 bombers to carry nuclear rather than conventional weapons. In this environment, even a relatively minor deterioration in relations might generate domestic political pressure in Russia for regaining parity. American domestic pressure would trigger a response, and an arms race could reignite.
Frank von Hippel, among others, has recommended a long-term strategy of "deep cuts," in which the nuclear powers would mutually agree to reduce their arsenals to a far greater extent than arms reduction negotiations have contemplated to date, to perhaps 200 nuclear weapons each. Even most of these would be stored rather than deployed. As von Hippel notes, "ten survivable warheads would still be a terrifying deterrent. A single 450-kiloton Trident II warhead, for example, could destroy an urban area of 200 square kilometers-roughly the size of Washington or St. Louis"(1997, p. 13).
Von Hippel does not in fact recommend targeting cities, even with these reduced arsenals. The more relevant point is that few nuclear weapons are required for effective deterrence. The contempora...