David Aaronovitch: Bin Laden isn't Gerry Adams with a flamboyant beard

'The two men belong to different moral universes, and we must never, ever forget that fact'

A lot of people lately have been reaching up to the top shelf and getting down their copy of Old Aaron's Book of Simple Truths and Conventional Wisdoms, and looking up the entry on terrorism. Which says that one man's terrorist is another man's freedom fighter, that we always have to negotiate with them in the end, and that the wicked things states do are often as bad as the actions of terrorists. Or, for those preferring an alternative set of simplicities, you can look at another entry and discover that all terrorists are bad, a leopard never changes its spots, and that they must all be destroyed.

The coincidence this week of the continued bombing of Afghanistan and the beginning of genuine IRA arms decommissioning has led to this page in the volume being particularly well-thumbed. In Belfast some Unionists have held up placards depicting the Sinn Fein leader Gerry Adams in a bin Laden beard. Bin Laden is a mad bearded terrorist who we have to bring to justice, Gerry Adams is a bearded terrorist, so therefore he must be mad and must be brought to justice.

Others also see a relationship. Four years ago one of these complained on television that "they receive the highest top official of the Irish Republican Army [Gerry Adams] at the White House as a political leader, while woe, all woe is the Muslims if they cry out for their rights". Yep, that was Osama, speaking to CNN's Peter Arnett.

Adams, who is himself said to have lost friends in the New York attack, is unlikely to be impressed by the parallel. And I don't blame him. For a decade and a half he has been working assiduously to draw the republican movement away from its sentimental attachment to guns and death, and towards politics and life.

In that time, of course, he's carried the coffins of bungling bombers and sought to justify terrorist "collateral damage". But would the world have been better off had he decided to turn his back on republicanism after Enniskillen? Absolutely not. Whatever the man once was, he is now a statesman and a deliverer of peace.

Aha! As (says the conventional wisdom of unthinking progressives) in their time were Nelson Mandela, Yasser Arafat and (much more grudgingly now) that old Stern gang stalwart, Menachem Begin. We start off fighting them, saying that we will never negotiate, but in the end we will always talk to them and give them pretty much what they were asking for in the first place.

Look, they argue, and you will see the similarities. The mad, paradise-seeking martyrdom of the World Trade Centre suicide attackers shares some characteristics with the Irish martyr romances. Oh, those rebel songs and their sanguinary myths: "And Rory McCorley goes to die on the bridge of Tuam today." The heroic murals: on a Belfast wall a heroic republican soldier lass with good legs and long hair points her rifle at some unseen Brit. Who turns out to be a boy going shopping in Warrington.

Unlike the South African struggle, the IRA campaign was, after 1972, squalid and avoidable. The republican movement had open to it all the mechanisms of a democratic life: it could stand in elections, say what it liked and – if it could convince enough Protestants of its case – it could win. Instead it chose to try to shoot its way to a "32-county socialist republic". One in the eye for the conventional wisdom because, far from winning its armed struggle, it lost.

Adams told his colleagues for years that political means were superior to military ones, and he was right. As long as the IRA used violence, successive British governments refused to deal with it, just as no one is talking to the Real IRA. It has taken 3,500 deaths and 30 years for republicans to understand that John Hume was right all along.

The IRA was different from sub-Che egotists like Carlos the Jackal (who was essentially an armed Chomskyian); different from the PLO who hijacked planes with people aboard who had nothing to do with their struggle; was different again from the ANC's Umkhonto we Sizwe, which had no democratic outlet, but actually hardly indulged in an armed struggle, preferring international action.

Nor is terrorism necessarily or even mainly an extreme expression of injustice, of alienation or a cry to be heard. Unless we are prepared to find the oppression that lies behind Timothy McVeigh, David Copeland, The Red Hand Commandos or the Turkish Grey Wolves. The truth is that people are as willing to die and kill in bad causes as they are in good.

It is also uncomfortable that states, including democratic ones, have found other people's terrorists to be very useful. During the Cold War, proxy guerrillas were armed, funded and blessed by both sides. Washington loved the mujahedin and the Nicaraguan Contras, East Germany sheltered members of the Baader Meinhof gang. Earlier this week 30 or so Pakistani "militants" were blown up in Kabul by an American bomb. They were members of a Kashmiri group, one of whose recent actions was to behead a few European backpackers.

Even so bin Laden is epiphenomenal. He has no demands in the conventional sense. If you wanted to stop him by political means (other than by entirely remaking the world so that nobody would ever support him – not easy), how could you do it?

Bin Laden doesn't, after all, just want the US to stop supporting Israel, he wants Israel destroyed. He doesn't just want no US troops in the region. "In our religion," he told Arnett, "it is not permissible for any non-Muslim to stay in our country". Meaning Saudi Arabia, but quite possibly including Palestine. Bosnia, for him, is part of the Islamic world. And America must stop oppressing Muslims "in the whole world", which could mean doing anything that bin Laden disapproves of anywhere from Indonesia to Morocco.

If they don't? He told Arnett: "As for what you asked regarding the American people, they are not exonerated from responsibility, because they chose this government and voted for it despite their knowledge of its crimes." So if America offends Muslims, or there is any issue in which Muslims are in dispute with others and they are thwarted, then bin Laden reserves the right to blast, poison or incinerate ordinary Americans – and I suppose Brits – to kingdom come. In doing so (and unlike Gerry Adams even in his beret and dark glasses phase), he is acting on the express instructions of the divine. Actually, he probably thinks he is divine himself.

There is a problem for our own leaders in all this. Obviously it is time to recognise the sins of the past, and the terrible immorality that lay behind the creation of proxy terrorism. I predict a lot of extradition in the months and years ahead. And it is both irritating and meaningless merely to talk about a generic War on Terrorism.

But it is political cretinism to hint, as some on the left do, that there is some kind of relationship between a Mandela and a bin Laden. The two belong to different moral universes, and we must never, ever forget it.

David.Aaronovitch@btinternet.com