THE UNIMAGINABLE but ultimately inescapable truth is that we are going to have to get ready for war with Iran. Being of a free-speaking, free-thinking disposition, we generally find in the West that hand-wringing, finger-pointing and second-guessing come more easily to us than cold, strategic thinking. Confronted with nightmarish perils we instinctively choose to seize the opportunity to blame each other, cursing our domestic opponents for the situation they’ve put us in.

The rapidly intensifying crisis with regard to Iran exemplifies the phenomenon. On the right, it is said that the decision to let the Europeans play nuclear footsie with the mullahs in Iran for more than two years was a terrible blunder. Pacifist evasion is what the world has come to expect from continental Europe, but the decision by Condoleezza Rice, the US Secretary of State, to become an enabler to their procrastinations was of a different order of strategic error. An emboldened Tehran seized the chance to play them all along while advancing its ambitions in great leaps.

On the left the hands are being wrung over Iraq. It is argued that the decision to invade the wrong country has made our situation intolerably worse. Iran was always the bigger threat. While we were chasing phantom nuclear weapons in Mesopotamia, next door Iran was busy building real ones. Now we are enfeebled, militarily and politically, our diplomatic tools blunted beyond repair by the errors in Iraq.

I tend to side more with the former crowd (though let it not be said that the latter do not have a point) but it is important for all of us to understand that this debate is now for the birds. All that matters now is what we do.

The unavoidable reality is that we now need urgently to steel ourselves to the ugly probability that diplomacy will not now suffice: one or way or another, unconscionable acts of war may now be unavoidable.

Those who say war is unthinkable are right. Military strikes, even limited, targeted and accurate ones, will have devastating consequences for the region and for the world. They will, quite probably entrench and harden the Iranian regime. Even the young, hopeful democrats who despise their theocratic rulers and crave the freedoms of the West will pause at the sight of their country burnt and humiliated by the infidels.

A war, even a limited one, will almost certainly raise oil prices to recession-inducing levels, as Iran cuts itself off from global markets. The loss of Iranian supply and the already stretched nature of production in the Arab world and elsewhere means prices of $150 per barrel are easily imaginable. Military strikes will foster more violence in the Middle East, strengthen the insurgency in Iraq and Afghanistan, fuel anti-Western sentiment among Muslims everywhere and encourage more terrorism against us at home.

All true. All fearfully powerful arguments against the use of the military option. But multiplied together, squared, and then cubed, the weight of these arguments does not come close to matching the case for us to stop, by whatever means may be necessary, Iran from becoming a nuclear power.

If Iran gets safely and unmolested to nuclear status, it will be a threshold moment in the history of the world, up there with the Bolshevik Revolution and the coming of Hitler. What the country itself may do with those weapons, given its pledges, its recent history and its strategic objectives with regard to the US, Israel and their allies, is well known. We can reasonably assume that the refusal of the current Iranian leadership to accept the Holocaust as historical fact is simply a recognition of their own plans to redefine the notion as soon as they get a chance (“Now this is what we call a holocaust”). But this threat is only, incredibly, a relatively small part of the problem.

If Iran goes nuclear, it will demonstrate conclusively that even the world’s greatest superpower, unrivalled militarily, under a leadership of proven willingness to take bold military steps, could not stop a country as destabilising as Iran from achieving its nuclear ambitions.

No country in a region that is so riven by religious and ethnic hatreds will feel safe from the new regional superpower. No country in the region will be confident that the US and its allies will be able or willing to protect them from a nuclear strike by Iran. Nor will any regional power fear that the US and its allies will act to prevent them from emulating Iran. Say hello to a nuclear Syria, Egypt, Saudi Arabia.

Iran, of course, secure now behind its nuclear wall, will surely step up its campaign of terror around the world. It will become even more of a magnet and haven for terrorists. The terror training grounds of Afghanistan were always vulnerable if the West had the resolve. Protected by a nuclear-missile-owning state, Iranian camps will become impregnable.

And the kind of society we live in and cherish in the West, a long way from Tehran or Damascus, will change beyond recognition. We balk now at intrusive government measures to tap our phones or stop us saying incendiary things in mosques. Imagine how much more our freedoms will be curtailed if our governments fear we are just one telephone call or e-mail, one plane journey or truckload away from another Hiroshima.

Something short of military action may yet prevail on Iran. Perhaps sanctions will turn their leadership from its doomsday ambitions. Perhaps Russia can somehow be persuaded to give them an incentive to think again. But we can’t count on this optimistic scenario now. And so we must ready ourselves for what may be the unthinkable necessity.

Because in the end, preparation for war, by which I mean not military feasibility planning, or political and diplomatic manoeuvres but a psychological readiness, a personal willingness on all our parts to bear the terrible burdens that it will surely impose, may be our last real chance to ensure that we can avoid one.

gerard.baker@thetimes.co.uk

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