More on missile defense
By Jesse Taylor points out:
Missile defense is not a bad idea…in the abstract. Defending oneself from missiles, after all, was the basis of a seminal videogame in the 1980s, which made the point that stopping missiles from hitting us was not only useful for protecting your cities and missile bases, but was also entertaining and useful for impressing your teenage friends – even if you were in your 40s.
I think that he has hit on the most useful application of a missile defense system; its role in video games. I’ll even go a step further, and argue that you really can’t expect to succeed in the later stages of Civilization III unless you have a missile defense, as Alexander of the Greeks tends to play pretty fast and loose with his nukes. Losing half the population of your city really sucks, and your workers waste a lot of time cleaning up the radioactive waste.
Since apparently not everyone has thirty seconds to think about the actual merits and deficiencies of a missile defense system, I suppose that I’ll go through them. The upside of a missile defense system is that, if it works, it will shoot down missiles. This would allow the United States to fuck around with missile-owning countries like North Korea, Russia, and China without fear of retaliation, or at least until they threaten to aim their missiles at London or Tokyo.
The deficiencies of a missile defense system are several, and apply both to the extant program and to the ideal program. The existing program doesn’t work; there have been no successful field tests that meet even the least rigorous rubrics of testing. Right now, we can shoot down a missile that is attached to a beacon about 40% of the time when we know exactly where and when it is being fired. Not impressive. Moreover, the current system promises to be most ineffective against the type of missiles that North Korea is likely to launch. Missiles that fly on a reliable trajectory are easiest to hit, while those that wobble, fly of course, and are in general erratic tend to be much more difficult. Three guesses as to the accuracy of North Korean missiles, and the first two don’t count.
Even the ideal system has its problems. Any system we are likely to design will have a finite capacity to reliably shoot down enemy missiles. That means that we could expect with some confidence that a system could shoot down twenty missiles, but not a hundred; a hundred, but not four hundred, and so forth. Other countries will immediately have an incentive to construct more missile than we can reliably shoot down. Thus, we’ll have an arms race in short order. Building ICBMs is a lot cheaper than building ABMs, because the guidance and flight systems of and ICBM are much simpler. Thus, we’ll have an arms race in which the other guy spends $10 to our $100.
That’s bad, but we’ll also have what people call an innovation spiral. The Chinese, for example, will note that we have a missile defense. One response will be to build more missiles. Another will be to build missiles that are not vulnerable to the missile defense, such as nuclear tipped cruise missiles launched from aircraft or submarines. Another response will be to develop a strategic bomber arm. Another response will be to build less vulnerable ballistic missiles, such as SLBMs (submarine launched missiles) that can be fired from eleven miles off the coast, and will arrive in a couple minutes. Another response will be to develop countermeasures to fool our missile defense. If a ICBM costs $10 to the $100 of an ABM, a decoy that will likely fool the ABM probably costs about $1. As we build smarter ABMs, they will build smarter decoys, and will still hammer us on per unit cost.
Last but not least, if anyone ever believed that we actually had a reliable defense, they would have incentive for a preemptive strike. This is probably the least likely difficulty, but not one to be ignored when dealing with the China-Taiwan problem or the North Korea-South Korea problem.
Missile defense: Losing proposition anywhere but in a video game.