November 21, 2007: The U.S. Missile Defense Agency, building on a string of successful tests, recently awarded a contract for 29 more SM-3 missiles for Aegis warships. This is the start of the next phase of building a national missile defense system that will largely render the ICBM obsolete.

How is this so, when Russia alone has 560 ICBMs? One look at American plans for 38 ground-based interceptors and 55 SM-3s would not seem to make much of a dent (less than 20 percent, if all interceptor missiles hit their targets) in a Russian ICBM attack. First of all, this calculus ignores other countries. At least 25 countries have ballistic missiles. Some are less-than-model global citizens.

The system as it now stands, with 13 operational ground-based interceptors, and plans to increase to a total of 18 by the end of 2007, is already sufficient to have neutralized China's force of 24 DF-5 ICBMs. How is this so, considering that China has six more missiles that the U.S. has interceptors? Simple subtraction would seem to indicate that at least six ICBMs would get through to their targets in an attempted strike (which is possible – on at least one occasion, Chinese generals have threatened to use nukes if the U.S. and China came to blows over Taiwan).

The "leaky" missile defense system still provides a deterrent against launching attacks – because a country that does decide to launch missiles at the United States or any of its allies protected by a missile defense shield, will not know which of its missiles will fail to reach their targets. They need more ICBMs, and money spent on ICBMs is money that cannot be spent on carriers, amphibious ships, or other items needed for a successful invasion of Taiwan.

The SM-3 carries another edge. By operating from Aegis vessels, it means the U.S. can defend deployed forces. Countries with shorter-range missiles will also face the same problems that plague a potential ICBM attack. Which missiles get stopped, the ones targeting the American supply depots, or the ones targeting the air base? It's impossible to know for sure. And an American tripwire will have time to dig in, and get reinforcements from heavier forces.

Making matters worse for potential adversaries is the fact that the successful tests have made the missile defense system very hard for Congress to touch, even though the current leadership opposed a national missile defense system for years. By performing well, the missile defense system has made a lot of friends, and pulling the plug on a successful program can be a very hard sell politically.

As the missile defense system is built further, the success of an ICBM attack will become more uncertain. And that will be a huge deterrent to launching said attack in the first place, particularly when it is well known that the United States can respond – and its attack will not face a missile defense system. – Harold C. Hutchison ([email protected])