The west has picked a fight with Iran that it cannot win

Washington's kneejerk belligerence ignores Tehran's influence and the need for subtle engagement

Never pick a fight you know you cannot win. Or so I was told. Pick an argument if you must, but not a fight. Nothing I have read or heard in recent weeks suggests that fighting Iran over its nuclear enrichment programme makes any sense at all. The very talk of it - macho phrases about 'all options open' - suggests an international community so crazed with video game enforcement as to have lost the power of coherent thought.

Iran is a serious country, not another two-bit post-imperial rogue waiting to be slapped about the head by a white man. It is the fourth largest oil producer in the world. Its population is heading towards 80 million by 2010. Its capital, Tehran, is a mighty metropolis half as big again as London. Its culture is ancient and its political life is, to put it mildly, fluid.

All the following statements about Iran are true. There are powerful Iranians who want to build a nuclear bomb. There are powerful ones who do not. There are people in Iran who would like Israel to disappear. There are people who would not. There are people who would like Islamist rule. There are people who would not. There are people who long for some idiot western politician to declare war on them. There are people appalled at the prospect. The only question for western strategists is which of these people they want to help.

Of all the treaties passed in my lifetime the 1968 nuclear non-proliferation treaty (NPT) always seemed the most implausible. It was an insiders' club that any outsider could defy with a modicum of guile. So it has proved. America, sitting armed to the teeth across Korea's demilitarised zone, has let North Korea become a nuclear power despite a 1994 promise that it would not. America supported Israel in going nuclear. Britain and America did not balk at India doing so, nor Pakistan when it not only built a bomb but deceitfully disseminated its technology in defiance of sanctions. Three flagrant dissenters from the NPT are thus regarded by America as friends.

I would sleep happier if there were no Iranian bomb but a swamp of hypocrisy separates me from overly protesting it. Iran is a proud country that sits between nuclear Pakistan and India to its east, a nuclear Russia to its north and a nuclear Israel to its west. Adjacent Afghanistan and Iraq are occupied at will by a nuclear America, which backed Saddam Hussein in his 1980 invasion of Iran. How can we say such a country has 'no right' to nuclear defence?

None the less this month's reopening of the Natanz nuclear enrichment plant and two others, though purportedly for peaceful uses, was a clear act of defiance by Iran's new president, Mahmoud Ahmadinejad. Inspectors from the UN's International Atomic Energy Agency (IAEA) remain unsure whether it implies a secret weapons programme but the evidence for this is far stronger than, for instance, against Saddam Hussein. To have infuriated the IAEA's Mohamed ElBaradei takes some doing. As Saddam found, deviousness in nuclear matters is bound to arouse suspicion. Either way, the reopening yielded a strong diplomatic coalition of Europe, America, Russia and China in pleading with Ahmadinejad to desist.

On Monday, Washington's kneejerk belligerence put this coalition under immediate strain. In two weeks the IAEA must decide whether to report Iran to the UN security council for possible sanctions. There seems little point in doing this if China and Russia vetoes it or if there is no plan B for what to do if such pressure fails to halt enrichment, which seems certain. A clear sign of western floundering are speeches and editorials concluding that Iran 'should not take international concern lightly', the west should 'be on its guard' and everyone 'should think carefully'. It means nobody has a clue.

I cannot see how all this confrontation will stop Iran doing whatever it likes with its nuclear enrichment, which is reportedly years away from producing weapons-grade material. The bombing of carefully dispersed and buried sites might delay deployment. But given the inaccuracy of American bombers, the death and destruction caused to Iran's cities would be a gift to anti-western extremists and have every world terrorist reporting for duty.

Nor would the 'coward's war' of economic sanctions be any more effective. Refusing to play against Iranian footballers (hated by the clerics), boycotting artists, ostracising academics, embargoing commerce, freezing foreign bank accounts - so-called smart sanctions - are as counterproductive as could be imagined. Such feelgood gestures drive the enemies of an embattled regime into silence, poverty or exile. As Timothy Garton Ash wrote in these pages after a recent visit, western aggression 'would drain overnight its still large reservoir of anti-regime, mildly pro-western sentiment'.

By all accounts Ahmadinejad is not secure. He is subject to the supreme leader, Ayatollah Ali Khamenei. His foe, Akbar Hashemi Rafsanjani, retains some power. Tehran is not a Saddamist dictatorship or a Taliban autocracy. It is a shambolic oligarchy with bureaucrats and technocrats jostling for power with clerics. Despite a quarter century of effort, the latter have not created a truly fundamentalist islamic state. Iran is a classic candidate for the politics of subtle engagement.

This means strengthening every argument in the hands of those Iranians who do not want nuclear weapons or Israel eliminated, who crave a secular state and good relations with the west. No such argument embraces name-calling, sabre-rattling, sanctions or bombs.

At this very moment, US officials in Baghdad are on their knees begging Iran-backed Shia politicians and militias to help them get out of Iraq. From Basra to the suburbs of Baghdad, Iranian influence is dominant. Iranian posters adorned last month's elections. Whatever Bush and Blair thought they were doing by invading Iraq, they must have known the chief beneficiary from toppling the Sunni ascendancy would be Shia Iran. They cannot now deny the logic of their own policy. Democracy itself is putting half Iraq in thrall to its powerful neighbour.

Iran is the regional superstate. If ever there were a realpolitik demanding to be 'hugged close' it is this one, however distasteful its leader and his centrifuges. If you cannot stop a man buying a gun, the next best bet is to make him your friend, not your enemy.