WASHINGTON -- The cowboy has been retired. Multilateralism is back. Diplomacy is king. That's the conventional wisdom about Bush's second term: Under the influence of Secretary of State Condoleezza Rice, the administration has finally embraced ``the allies.''

This is considered a radical change of course. It is not. Even the most ardent unilateralist always prefers multilateral support under one of two conditions: (1) there is something the allies will actually help accomplish, or (2) there is nothing to be done anyway, so multilateralism gives you the cover of appearing to do something.

The six-party negotiations on North Korea are an example of the second. North Korea went nuclear a long time ago. Our time to act was during the Bush 41 and Clinton administrations. Nothing was done. And nothing can be done now. Once a country has gone nuclear, there is no return. The nukes themselves act as a deterrent against military measures. And no diplomat, however mellifluous, is going to talk a nuclear North Korea into dismantling the one thing that gives it any significance in the world.

Like most multilateral efforts, the six-party talks give only the appearance of activity, thereby providing cover to a hopelessly lost cause. Nothing wrong with that kind of multilateralism.

Lebanon is an example of the other category -- multilateralism that might actually accomplish something. The U.S. worked assiduously with France to draft a Security Council resolution that would create a powerful international force, and thus a real buffer, in south Lebanon. However, when the Lebanese government and the Arab League objected, France became their lawyer and renegotiated the draft with the U.S. The State Department acquiesced to a far weaker resolution on the quite reasonable grounds that since France was going to lead and be the major participant in the international force, we should not be dictating the terms under which the force would operate.

But we underestimated French perfidy. (Overestimating it is mathematically impossible.) Once the resolution was passed, France announced that instead of the expected 5,000 troops, it would be sending 200. The French defense minister explained that they were not going to send out soldiers under a limited mandate and weak rules of engagement -- precisely the mandate and rules of engagement that the French had just gotten us to agree to.

This breathtaking duplicity -- payback for the Louisiana Purchase? -- left the State Department red-faced. (It recouped somewhat when, Thursday night, France reportedly agreed to send 1,500 to 2000 troops.) But the setback was minor compared to what we now face with Iran. Hezbollah in south Lebanon is a major irritant, but a nuclear Iran is a major strategic threat.

The problem is not quite as intractable as North Korea because Iran has not crossed the nuclear threshold. And American diplomacy has, up until now, been defensible. Secretary Rice's June initiative, postponing Security Council debate on sanctions, was meant to keep the allies on board. It offered Iran a major array of economic and diplomatic incentives (including talks with the U.S.), with but a single condition: Iran had to verifiably halt uranium enrichment.

Iran's answer is now in. It will not. Indeed, on the day before it sent its reply to the U.N., Iran barred IAEA inspectors from the uranium enrichment facilities at Natanz. Our exercise in multilateralism has now reached criticality. We never expected Iran to respond positively. The whole point in going the extra mile was to demonstrate American good will and thus get our partners to support real sanctions at the Security Council.

But this will not work. The Russians and Chinese are already sending signals that they will allow Iran to endlessly drag out the process. Even if we do get sanctions imposed on Iran, they will undoubtedly be weak. And even if they are strong, the mullahs will not give up the glory and dominion (especially over the Arabs) that come with the bomb in exchange for a mess of pottage.

Realistically speaking, the point of this multilateral exercise cannot be to stop Iran's nuclear program by diplomacy. That has always been a fantasy. It will take military means. There will be terrible consequences from such an attack. These must be weighed against the terrible consequences of allowing an openly apocalyptic Iranian leadership from acquiring weapons of genocide.

The point of the current elaborate exercise in multilateral diplomacy is to slightly alter that future calculation. By demonstrating extraordinary forbearance and accommodation, perhaps we will have purchased the acquiescence of our closest allies -- Britain, Germany and, yes, France -- to a military strike on that fateful day when diplomacy has run its course.