But even if such defense were to become technically feasible, the main effect would be to change the terrorist threat without reducing it very much. That is because the better a missile defense worked, the more likely it would be that terrorists would divert their efforts to means of delivering chemical and biological weapons. Simple delivery methods, ranging from small airplanes to smuggled components, would be a lot cheaper than missile defense. America should deter all means of delivery by making clear that those using such weapons would be obliterated. The real dangers to world stability lie in U.S. unilateralism and over-response by the rest of the world at a time when chaos theory is more relevant than deterrence calculus.
Old think provides no refuge.
The writer, an economist and defense analyst, is a former official in the U.S. executive and legislative branches. He contributed this comment to the International Herald Tribune.