BAD CAUSES NEED martyrs. The War on Terror, as conceived by the US President and the British Prime Minister, is a bad cause, and this week in Istanbul it has claimed new martyrs. Both sides in this war — the US-led coalition and the al-Qaeda terrorist network — will be quietly reinforced by what has happened: reinforced in their prejudices; reinforced in their own self-belief, and reinforced in the new support this will bring them. Both gain. The world loses.

When news reached me of Thursday's outrage, I had just reread this passage in The Mill on the Floss, by George Eliot: “To minds strongly marked by the positive and negative qualities that create severity — strength of will, conscious rectitude of purpose, narrowness of imagination and intellect, great powers of self-control and a disposition to extert control over others — prejudices come as the natural food of tendencies which can get no sustenance out of that complex, fragmentary, doubt-provoking knowledge which we call truth.”

The explosions in Istanbul are good news for prejudice and good news for George W. Bush and Tony Blair. I do not imply that either leader will take any pleasure in the news. They will grieve for the dead, like everyone else.

But an explosion simplifies. It simplifies — just as a big IRA bomb in the midst of a delicate and messy peace process seems to simplify. “No surrender” is the instinctive human reaction. The peacemakers’ babble is silenced, and people take sides. An iron fist is demanded. It will be now, after Istanbul.

Atrocious acts of unprovoked aggression favour the iron-fisters in three distinct ways. First, they appear to confirm what the iron-fisters have always said: that the threat is huge, and imminent, and that we all are targets. As this newspaper’s leading article yesterday put it: “The notion that the President and the Prime Minister were deliberately exaggerating the threat from terror for their political ends, never a persuasive one, has been rendered implausible.”

Secondly, an atrocity lends support to the argument that there is no ducking choices, “no dealing” with an aggressor and no middle ground; that reasoning is useless, that calls for restraint are delusive, and that all must now take sides. Staying on the sidelines is characterised as a distraction. As the same leading article put it: “The demonstrations that had been been organised against Mr Bush and Mr Blair yesterday looked irrelevant and naive.”

Thirdly, public outrage after an atrocity backs up the iron-fisters’ demand they be given a free hand and the benefit of public doubt. Our leading article put it like this: “The task ... will need to be pursued with renewed vigour. It is not a conventional sort of conflict and its successes are unavoidably shrouded in secrecy. It ... requires the public to place faith in its leaders and their decisions.”

Such — I predict — will be the predominating voices in the aftermath of Thursday’s atrocity. There may be a few (mine among them) who read other messages from the rubble, but, in the saloon-bar argument about whether Tony Blair has been wise to hug George W. Bush so close, the sceptics’ case has become more difficult. I am under no illusion: the winners are those who urge a closer hug and a bigger fight. What care we any longer about squabbles over US steel tariffs, now that the British Consul-General in Istanbul lies dead? When innocent people are bleeding, arguments about the wisdom or intelligence of an ally’s approach are made to seem almost in bad taste.

But when good taste occludes reason, go into battle for bad taste. It is bad taste, but true, to say that terrorist atrocities are good for the careers of our Prime Minister and the US President. It is bad taste, but true, to say that Britain would probably not have been the target in Turkey on Thursday, had our country not been a key member of Mr Bush’s coalition. It is bad taste, but true, to say that British interests and British lives are paying to sustain in office a prime minister who has joined the Americans in a colossal military and diplomatic blunder and now has no choice but to plough on with it.

The furrow will be long and bloody. It is bad taste, but true, to say that if the only way of protecting ourselves worldwide is through enhanced security and the violent pursuit of those who threaten us, then all is lost. If the al-Qaeda network is as our leaders describe it, then what force on earth can surround every Briton and British interest abroad with armour, proof against a suicide bomber? We must resign ourselves to decades of exposure to random explosions all over the globe, directed against ourselves and against those who do business with us. Alongside the Americans, our two nations will pay the price alone.

ONE PERFECTLY honourable response is to say, in the words of that patriotic cartoon at the outbreak of the Second World War: “Very well then: alone.” For, if we grant one key but unspoken premise in the argument then the US-British position can be seen as the only brave conclusion: stand up to the enemy and face the flak.

On this reasoning, and assuming again that key but unspoken premise, there is also a cowardly conclusion. Sharing Washington’s analysis of the al-Qaeda threat, we could still conclude that it might have been in Britain’s interests to hang back, along with Germany and France, and leave the Americans to take the hits. Only a junior partner in the coalition, Britain is not indispensable to the effort, and so — self-interestedly — we could have left it to others.

That would have been ignoble, of course. And this week’s explosions in Turkey will be widely seen as having sketched, in the starkest outline the choice, the ignobility of the response Britain did not offer, and the nobility of one we did. On some accounts there is a hint that France and Germany have knowingly chosen the ignoble option. On some accounts. But I mentioned a key but unspoken premise lying beneath both the noble and the ignoble options. It is this. That we live in a world divided between darkness and light, and there is nothing we can do about that except pick sides and fight.

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