So far, so good. But in addition to ICBMs, cruise missiles also pose a potentially huge threat. ICBMs fly high and fast. Cruise missiles fly low and (relatively) slow. Stopping them presents distinct signal-processing challenges and will require radars that look in different directions and likely on different frequencies-and even different or substantially modified antimissile weapons. Yet while we are pouring billions into ICBM defense, the United States is vastly underinvested in cruise missile defense. In fact, says Owen Cote Jr., an associate director of MIT’s Security Studies Program, when it comes to cruise missiles, our plans include “no significant defense at all.”
Now let’s look at deployment. The Alaska-bound system, which targets midcourse interceptions, hasn’t come close to proving it can discriminate between real missiles and the decoys that any real attack would almost certainly employ. The main advantage of such a system is that it can defend against missiles launched from almost anywhere, whereas boost phase systems must be deployed in the vicinity of specific threats. But since we aren’t facing attacks from almost anywhere, a more reasonable first step would be to deploy boost phase systems around such troubled areas as North Korea and to follow with midcourse systems as we advance the technology. Or, as Cote puts it, “Get in soon on a reasonable scale in a way that’s tailored to countering real threats, not imagined ones.”
Of course, even a perfect missile-defense system can never make nuclear weapons “obsolete” or guarantee the United States won’t be attacked-be it by conventional aircraft or a terrorist operation. But missile defense needs to be pursued. Intelligently. The answer isn’t to rush ahead with unproved systems. It’s to roll out a defense in phases, at first deploying a limited system comprising technologies that are known to work and adding layers as new elements prove their effectiveness. At the same time, we cannot neglect development of a nationwide system to counter cruise missiles, so that sometime in the next 10 to 20 years we have an integrated, well-tested, comprehensive defense against both types of attack.
Only then will we have a reasonable chance of ensuring that the missile won’t get through.