Some debates just never go away. The Clinton administration is back again pressing Congress for passage of the Comprehensive Test Ban Treaty (CTBT). This is part of a final-legacy push that includes a Middle East peace for just-in-time delivery by September 2000.

The argument for the test ban is that it will prevent nuclear proliferation. If countries cannot test nukes, they will not build them because they won't know if they work. Ratifying the CTBT is supposed to close the testing option for would-be nuclear powers.

We sign. They desist. How exactly does this work?

As a Washington Post editorial explains, one of the ways to "induce would-be proliferators to get off the nuclear track" is "if the nuclear powers showed themselves ready to accept some increasing part of the discipline they are calling on non-nuclear others to accept." The power of example of the greatest nuclear country is expected to induce other countries to follow suit.

History has not been kind to this argument. The most dramatic counterexamples, of course, are rogue states such as North Korea, Iraq and Iran. They don't sign treaties and, even when they do, they set out to break them clandestinely from the first day. Moral suasion does not sway them.

More interesting is the case of friendly countries such as India and Pakistan. They are exactly the kind of countries whose nuclear ambitions the American example of restraint is supposed to mollify.

Well, then. The United States has not exploded a nuclear bomb either above or below ground since 1992. In 1993, President Clinton made it official by declaring a total moratorium on U.S. testing. Then last year, India and Pakistan went ahead and exploded a series of nuclear bombs. So much for moral suasion. Why did they do it? Because of this obvious, if inconvenient, truth: Nuclear weapons are the supreme military asset. Not that they necessarily will be used in warfare. But their very possession transforms the geopolitical status of the possessor. The possessor acquires not just aggressive power but, even more important, a deterrent capacity as well.

Ask yourself: Would we have launched the Persian Gulf War if Iraq had been bristling with nukes?

This truth is easy for Americans to forget because we have so much conventional strength that our nuclear forces appear superfluous, even vestigial. Lesser countries, however, recognize the political and diplomatic power conveyed by nuclear weapons.

They want the nuclear option. For good reason. And they will not forgo it because they are moved by the moral example of the United States. Nations follow their interests, not norms.

Okay, say the test ban advocates. If not swayed by American example, they will be swayed by the penalties for breaking an international norm.

What penalties? China exploded test after test until it had satisfied itself that its arsenal was in good shape, then quit in 1996. India and Pakistan broke both the norm on nuclear testing and nonproliferation. North Korea openly flouted the Nuclear Non-Proliferation Treaty.

Were any of these countries sanctioned? North Korea was actually rewarded with enormous diplomatic and financial inducements -- including billions of dollars in fuel and food aid -- to act nice. India and Pakistan got slapped on the wrist for a couple of months.

That's it. Why? Because these countries are either too important (India) or too scary (North Korea). Despite our pretensions, for America too, interests trump norms.

Whether the United States signs a ban on nuclear testing will not affect the course of proliferation. But it will affect the nuclear status of the United States.

In the absence of testing, the American nuclear arsenal, the most sophisticated on the globe and thus the most in need of testing to ensure its safety and reliability, will degrade over time. As its reliability declines, it becomes unusable. For the United States, the unintended effect of a test ban is gradual disarmament.

Well, maybe not so unintended. For the more extreme advocates of the test ban, nonproliferation is the ostensible argument, but disarmament is the real objective. The Ban the Bomb and Nuclear Freeze movements have been discredited by history, but their adherents have found a back door. A nuclear test ban is that door. For them, the test ban is part of a larger movement: the war against weapons. It finds expression in such touching and useless exercises as the land mine convention, the biological weapons convention, etc. The test ban, unfortunately, is more than touching and useless. It may actually work -- to disarm not the North Koreas of the world but the United States.