The US will conduct a crucial test today of an antimissile defense system that, if deployed, could jeopardize two of the world's most significant arms-control agreements.
The test will take place more than 100 miles above the Pacific Ocean, where a self-guided "kill vehicle" will separate from its rocket booster and try to collide with an incoming missile.
If successful, it will be the Pentagon's second "metal on metal" hit in its development of a national missile-defense system, and the Department of Defense likely will recommend to President Clinton in June that the descendant of "star wars" be deployed, according to a department official.
But while a hit may answer some of the technological questions surrounding missile defense, it will do little to assuage concerns of two of the program's loudest critics: Russia and China.
Both countries are worried that, if the US perfected the system, it would protect the US and undermine the deterrence of their own long-range nuclear missiles, possibly sparking another high-tech arms race. It is for that reason that the US and the Soviet Union agreed upon the Anti-Ballistic Missile (ABM) Treaty in 1972.
National defense is also opposed by America's European allies, who worry that the system will negate the risk they now share with the US, and force them either to invest in a system of their own or become vulnerable as a proxy target.
For the US, however, the prospect of having umbrella protection of all 50 states is almost irresistible. It is supported in principle by most politicians, with Democrats preferring a slower timetable and Republicans wanting to deploy as soon as possible - even if it is at the expense of the ABM treaty.
Officials here have taken every chance they get to pressure Russia into amending the ABM treaty to allow for a limited national missile-defense system. The State Department argues that it is designed to stop a limited attack from a rogue nation such as North Korea or Iran - not the shower of missiles that Russia is capable of launching.
But amid deteriorating relations between Washington and Moscow, the Russians have so far refused to amend the treaty. Furthermore, acting Russian President Vladimir Putin is likely to make ratification of another treaty, START 2, contingent upon the US abiding by the ABM treaty.
START 2, which would require Russia and the US to drastically reduce their nuclear-arms stocks, has been approved by the US but is still awaiting a vote in the Russian Duma. If it were tied to the ABM treaty, the death of one would mean the death of both.
"For a substantial time this would end the reductions of strategic offensive forces," says Spurgeon Keeny, the director of the Washington-based Arms Control Association.
China is equally - if not more - troubled by the possibility that the US could develop a working national missile defense.
Some analysts say the Chinese think this missile defense would be designed for them - not a poor country like North Korea whose real missile capacities are still unknown. Recent satellite photos of North Korea's primary missile test site, for example, indicate their program may be less developed than experts thought.
China, on the other hand, is thought to have 20 to 30 intercontinental ballistic missiles that probably could be neutralized by the US.
"North Korea is an absurd reason to make such a high-risk decision," says Charles Ferguson of the American Federation of Scientists. "No other country in the world shares the fear that North Korea is an imminent nuclear threat."
Experts predict that the Chinese would respond to a missile shield by building more-sophisticated projectiles or putting multiple warheads on them. Both techniques would allow them to overwhelm a limited defense.
"Even a very small national missile defense would be a threat to Chinese retaliatory ability," says Li Bin, a Chinese physicist and nonproliferation expert who visited Washington the week before the test.
Yet despite the debate about the effects of deploying a limited national missile-defense system, questions remain about whether the system is technologically feasible.
Problems are likely to arise, analysts say, when an incoming projectile is accompanied by decoys. The decoys, for instance, could confuse the kill vehicle, which, after separating from the booster, has only seconds to determine the real target.
In the first airborne test, which the Pentagon deemed a success, the kill vehicle first identified a decoy balloon and then hit the real target nearby, in part by chance. Defense officials acknowledge that the project is moving at an unusually fast pace. They also say their efforts are limited by political concerns - such as trying to work within the confines of the ABM treaty.
"Will somebody please tell us where we're going?" asked one exasperated Pentagon official.
In today's test, to be launched high over the Pacific Ocean, the system used to shoot down a dummy missile will be only a skeleton of the final product.
Few of the different components - radar, communications, and launch - will be integrated. There will be only one decoy.
And the target missile will carry a tracking device so that command and control knows when it's coming and from where.
(c) Copyright 2000. The Christian Science Publishing Society