Meeting the test.

It is not often that Congress leads. It did so in September 1992, when it forced President George Bush--in exchange for funding the supercollider--to accept a nine-month moratorium on U.S. nuclear testing and an end to all nuclear tests by 1996. It did so again last month when it persuaded a wavering President Bill Clinton to forswear testing now, unless and until another country goes first. Does Congress lead wisely?

Of all weapons of mass destruction, nothing else compares with nuclear weapons. Chemical and biological weapons may be terrifying, but they do not pack the overwhelming destructive power of nuclear weapons. The thought of a terrorist on the loose with such a weapon is a nightmare; the thought of an enemy nation--or of ourselves--using its nuclear arsenal is, finally, dumbfounding.

Yet the fact is, nuclear weapons, once developed--particularly on a massive scale by the five permanent members of the UN Security Council--acquired a life of their own. If for no other reason than to deter someone else's use of them, they are here to stay, at least for the foreseeable future. There is a demand for them and willing suppliers: Countries and terrorists alike are scheming and shopping. This gives plausibility to the arguments of nuclear weapons' proponents who question the wisdom of a testing moratorium. As Charles Krauthammer has observed (Washington Post, July 16), since it is absurd to pretend that nuclear weapons don't matter, wouldn't it be folly to let ours "rust," to allow them to become unreliable by refusing to test them? This is a fair question, but the issues of proliferation and testing must not be fused. A moratorium on U.S. testing will do nothing to encourage proliferation. On the contrary, it may slow it.

Nuclear tests are no longer needed to verify either the safety or the reliability of the U.S. nuclear arsenal. That is what convinced Congress that further tests are not needed. By simply testing components and using other nonnuclear tests, we already have adequate--and significantly less expensive--means of maintaining the readiness and safety of the U.S. deterrent. Furthermore, the United States now possesses all the materials required for maintaining its nuclear arsenal, as well as for its currently planned future weapons systems. If, over a period of decades, some nuclear components do degrade, they can be refabricated by means of well-tested techniques that do not entail full-scale nuclear testing. In short, there may be something rotten about nuclear weapons but the U.S. arsenal is not rusting--nor will it.

There are inherent dangers in nuclear testing, both material and moral. The physical waste and nuclear fallout produced by such tests are very real; they are a growing concern. The effect on attitudes is even more corrosive. As Frank von Hippel, a physicist and international affairs professor at Princeton, notes, nuclear testing "is taken as a symbol worldwide that nuclear weapons are usable. That undermines the nonproliferation regime in general, and it plays into the argument that the North Koreans have been making that our nuclear weapons represent a threat to them" (Arms Control Today, July/August 1993).

It is true that by refraining from nuclear testing the United States does not guarantee that other countries will not gain access to nuclear weapons; nor does its unilateral action prevent other countries from testing in the future. But the Clinton decision raises the moral ante against resuming testing, both for ourselves and for others. Since the U.S. moratorium went into effect last year, no other country has tested. And, by promising to enter into a comprehensive test ban treaty, as the U.S. and Russia have agreed to do in 1996, the possibility is heightened that countries such as India and Pakistan--nations that have refused to sign on to the Nonproliferation Treaty because it discriminates against nuclear have-nots--might agree to sign a comprehensive test ban.

But even this happy development would not protect the world from the nuclear genie. That will take untiring vigilance, a reduction in the world's store of processed uranium and plutonium, and eventually some breakthrough in developing a truly common security.

Since the end of the Gulf War it has become clear that Iraq not only came close to developing a bomb, but that it skillfully evaded the UN's International Atomic Energy Agency's monitoring strictures, buying whatever parts it needed from willing Western manufacturers. The weaknesses of the IAEA were exposed, almost gleefully, by its critics. As a result, however, the agency has been strengthened. Its recent role in revealing the state of nuclear weapons' development in North Korea, as well as its success in forcing Iraq to allow intrusive monitoring, both indicate the IAEA's growing stature and competency. These need further strengthening. More financing would help. The IAEA's entire yearly budget remains a paltry $60 million, far below the cost of a single U.S. nuclear test ($100 million).

Nuclear testing ought to be a thing of the past. The need for nuclear vigilance will never be. It is the price of human freedom and survival in a post-Hiroshima age.