The main government destabilized by North Korea's claimed nuclear explosion is clearly the government of the United States. Washington said it would prevent this from happening.

The Clinton administration negotiated with an opaque Pyongyang to exchange security assurances and qualified help in peaceful nuclear-power development for an unreliable promise not to develop weapons. The Bush administration spurned negotiation, insulted Kim Jong Il and made empty threats.

However, this is only a step in what probably will be the eventual failure of the entire nonproliferation effort. A complete breakdown is likely so long as the five governments recognized in 1968 as legitimate possessors of nuclear weapons do not honor their commitments under the Nuclear Nonproliferation Treaty to reduce and eventually eliminate their own nuclear arsenals.

The North Korean test is a demonstration to Washington that it can't keep - and improve - its own nuclear forces and expect the nonproliferation treaty to survive.

A system that allows only the original five nuclear powers - now illegally joined by Israel, India, Pakistan and North Korea - to possess these arms cannot last. Nuclear weapons will spread to any country that considers itself at risk from an existing nuclear state.

The promise of the five eventually to renounce the nuclear weapon was never convincing. Since then, the evidence has been that none will do so. Certainly the United States will not. This reality destroys the utility and relevance of the treaty. North Korea even went to the trouble of formally withdrawing from the treaty in January 2003, after the Bush administration denounced Pyongyang.

The North Korean test and Iran's supposed - if unconfirmed - intention to acquire nuclear weapons are reactions to what is seen as the threat of American intervention to bring about "regime change." The only value of a nuclear weapon to a small or relatively weak country is to deter attack, intrusion or interference by a more powerful country.

Nuclear weapons may not even be entirely convincing in that role because their destructive power is disproportionate to their actual utility. This is a source of unpredictability, and hence of deterrence through uncertainty, but it is also an invitation to extinction if the enemy is sufficiently ruthless.

Even a more powerful attacker would pause at the threat of a nuclear reaction. In the North Korean case, suppose that a conventional American attack were followed by a Hiroshima-scale retaliation against Seoul (not only South Korea's capital but also the headquarters of U.S. forces in the country). Who would have gained what?

Many intelligent people spent the 1950s and 1960s trying to think of clever ways to use nuclear weapons to advance national objectives, with no great success.

If the enemy possesses nuclear weapons, no matter how ingenious the offensive tactics, the risk of failure or of overwhelming retaliation is usually unacceptably high. We may be thankful that the usefulness of nuclear weapons nearly always comes down to deterrence, certainly so for countries like North Korea or Iran. And that is all they want from them.

The Americans and Israelis calling for war with Iran talk about Iranian nuclear aggression, nuclear blackmail or bestowing nuclear weapons on terrorists. None of this is serious.

You don't attack or blackmail other states unless you have what the nuclear planner calls an assured second-strike capability. That is, you have to be able to guarantee that even if your victim strikes back, you can still inflict unacceptable damage on him in retaliation: hence, it is not worthwhile for him to respond. Neither Iran nor North Korea will be able to do that for a very long time. You need hardened missile silos or submarines at sea - the panoply of the Cold War.

As for giving nuclear weapons to terrorists: Since missiles and explosions can be traced back to their manufacturers, no matter who pulls the trigger, that is not a prudent course of action.

The world has undoubtedly been lucky to limit the spread of nuclear weapons, to the extent that its has, since 1945. The Nuclear Nonproliferation Treaty was a good idea, but the major powers did not sign it in good faith, and have not lived up to it.

The threats offered by the major powers to "rogue states" - or to any state lacking conventional defenses - is an irresistible invitation to proliferation. The one good thing that can be said about the situation in which we now find ourselves is that the Japanese and Chinese governments are going to be even more careful, and more cooperative, than they were in the past.

Copyright © 2006 the International Herald Tribune

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