OUT OF EVERY CRISIS, an opportunity appears. Now that the intervention in Iraq is universally recognised as a military and diplomatic disaster, the question is whether America and Britain could yet snatch victory from the jaws of defeat. Reflecting on the only previous time that American arms have been so comprehensively defeated suggests a surprisingly encouraging answer, not only for America, but also for the world as a whole.

When Richard Nixon was forced to abandon Vietnam, reducing the US commitment of half a million troops in 1970 to just 16,000 non-combatant “advisers” by the time of the presidential election in November 1972, the portents for world peace looked even worse than they do today. The Communist menace at that time seemed at least as dangerous to most Americans in the 1960s as Islamism does today, but what almost nobody realised at the time was that, in parallel with America’s effective surrender to Communism in Vietnam, Henry Kissinger was conducting a quiet diplomatic process. This process — the establishment of diplomatic relations with Communist China, which culminated with Nixon’s trip to Beijing in February 1972 — turned out to be infinitely more important to global security than the loss of Vietnam. Within nine months of Nixon’s visit, the last American combat troops were pulled out of Vietnam and two years later the whole of Indo-China had been abandoned to the Communists.

What turned out to be far more important, however, was that America’s diplomatic manoeuvre drove an enormous wedge between Communist China and Russia. By the mid-1970s China had become a conservative force for stability, rather than revolution, in Asia, and power started to shift inexorably from the firebrands of the Cultural Revolution to the pragmatists in Beijing.

The question raised by this oversimplified potted history is whether some similar diplomatic phoenix might conceivably emerge from the ashes of US policy in Iraq. Could a diplomatic overture to Iran be the analogue of Nixon’s opening to China? Could James Baker be the Kissinger for President Bush? For any dialogue with Iran (or Syria) to succeed, Bush would have to eat a lot of words. He would have to recognise that America is now the supplicant, just as Nixon did when he went to China. If Tehran helped to stabilise Iraq, it would be doing Washington a favour, not the other way round. To get such a process started, the US would have to repudiate the “axis of evil” doctrine and the goal of “regime change”, lift economic sanctions and offer Iran a formal guarantee of non-aggression.

To win real co-operation from Iran, it might well be necessary to go farther. Instead of demanding a suspension of the nuclear programme, America (and Britain) might have to accept that Iran will continue with enrichment and will probably, in due course, develop an atom bomb.

Today such a U-turn may seem unimaginable, but no more unthinkable than Nixon’s embrace of China at the height of the Vietnam War. The restoration of ties between Iran and the West would not change America or Europe one iota, but it could transform Iran.

Just as the US opening to China irreparably split the Communist world, the theocratic Islamic world could be split by an opening to Iran. On one side would be the irretrievable backwardness of Sunni Saudi Arabia, dominated by the medieval Wahhabi cult. On the other side would be an ascendant Shia Iran, whose relatively well-educated population might allow it to integrate with the modern world, even under a theocratic government. To achieve such a split, acceptance of Iran’s nuclear ambitions would be a price worth paying, especially as there is nothing America can now do anyway to stop them.

There would, of course, be two big losers from a US-Iranian rapprochement: Israel, at least as represented by its present leaders, and the Sunni strand of Islamic fundamentalism, as represented by the dominant political classes of Saudi Arabia, Pakistan and parts of Afghanistan.

Israel would certainly have to make concessions as part of any lasting rapprochement between the West and Iran. To satisfy even the moderate strand of Islamist thinking, these would have to include not only a credible movement towards a two-state solution with the Palestinians but, even more importantly for Iran’s religious leaders, a big territorial concession on the status of Jerusalem.

To satisfy the perfectly legitimate religious sensitivities, not only among the Muslims but also among many Christians, Israel would have to accept the conversion of Jerusalem into some kind of internationally guaranteed Jewish-Muslim-Christian condominium. Such concessions would be hard to accept for Israel, but it must realise that it can have little hope of long-term survival in a perpetually hostile Islamic environment — especially now that America can no longer be realistically viewed as a guarantor of security in the Middle East.

In any case, Israelis could take comfort from two undeniable facts. First, the reintegration of Iran into the community of nations could potentially turn Israel’s most threatening enemy into a neutral or even friendly state, as it was under the Shah. Secondly, an re-energised Iran could create a Shia counterweight to the religious influence of Saudi Arabia, whose brand of Sunni fundamentalism is the main source of inspiration for Islamic terrorism and extremism around the world.

It is Saudi Arabia, not Iran, that finances the Sunni mosques and madrassas in Pakistan, Afghanistan, Turkey, Indonesia, North Africa and increasingly also in Britain and Europe, where most Islamic terrorists are brainwashed and trained. A US- Iranian rapprochement that widened the split between fundamentalist Shias and Sunnis could tear the web of jihadi terror, just as the split between Moscow and Beijing broke the Communist nexus in the Cold War.

A generation after Nixon, will it be Bush, Clinton or McCain in Tehran?

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