In an effort to rally America after 11 September President Bush said: "There are good causes and bad causes. But there is no such thing as a good terrorist.

"Every nation must know that they are either with us or they are with the terrorist. No nation can pick and choose its terrorist friends," he added.

Mayor Rudolf Giuliani of New York summed up the rage of an entire nation - and the unimpeachable sense of righteousness on which that rage is founded - when he said: "Those who practise terrorism lose any right to have their cause understood ... We're right, they're wrong. It's as simple as that."

But the experience of those states who have had to fight terrorism over many years and even decades suggests it is seldom as simple as that.

Support

For many organisations who use terror, their strongest weapon is mass popular support inside the community on whose behalf they claim to be fighting.
Among Palestinians, Hamas recruits suicide bombers among the faithful in the mosques, and among the dispossessed in the Islamic organisations.

Hamas talent-spotters "scout" for new recruits. They set the most likely candidates tasks to test the strength of their nerves under pressure.

The father of one young suicide bomber, who blew himself up killing two Israeli soldiers, told us he had no idea his son was a supporter of Hamas until after the attack had taken place. "I am proud of what he did. He did it for God and our people," he said. The dead boy is a martyr in his community. His parents are venerated for their sacrifice.

What Hamas do is terrorism by any definition - the deliberate murder of the innocent, civilian and military alike, in pursuit of political objectives.

Irish precedent

But terror of this sort is difficult to defeat by military means alone, for the harder you hit it, the stronger it seems to grow. In the early 1990s, the then British Prime Minister John Major vowed that the Irish Republican Army (IRA), then still fighting to end British rule in Northern Ireland, would never succeed in bombing its way to the negotiating table.

But talks began and produced a peace agreement long before the IRA had decommissioned its arms. After three decades of blood-letting it took two remarkable leaps of faith.

The republican movement had to accept - and persuade its own supporters - that the 'armed struggle' it had been waging could not bring about the desired goal of a united Ireland.

Equally, the British Government had to concede that the terrorism could not be defeated by military/security means alone. Its political causes had to be addressed.

Dilemma

This is the most acute dilemma facing a democracy fighting terrorism - how to concede that some of the grievances that lead ordinary people to support terror organisations are indeed legitimate, without at the same time condoning or giving in to, the violent means deployed.

And what of state terrorism? The West has blamed Iraq, Sudan, Syria, Iran and Libya, among others, either for sponsoring terrorism directly or for harbouring those who commit terror.

But there is a problem here with definition. For the west also has a history of - in President Bush's words - "picking and choosing its terrorist friends". In the 1970s, a prominent Chilean dissident called Orlando Letelier was murdered by a car bomb in Washington DC, by an agent of the Chilean secret service, Dina.

Letelier had been a member of the democratically-elected government of President Salvador Allende, which was deposed by a military coup led by General Augusto Pinochet in 1973.

Letelier's murder was part of a plan called Operation Condor, carried out by the secret services of six South American countries, all with right-wing dictatorships, all with growing left-wing insurgencies at home.

The US Central Intelligence Agency (CIA) knew about Operation Condor - though there is no evidence that they knew in advance about the Letelier assassination - and lent it logistical and communications support.

Switching allegiances

In the 1980s, the United States armed and funded the Afghan mujahideen when it was fighting the Soviet forces who had invaded the country in 1979.The mujahideen (of which Osama Bin Laden was a part) used acts of terror then against civilian targets - blowing up schools and torturing and murdering captured Russian soldiers they had captured.

The danger in this is clear. If the war against terrorism is to be genuinely global - if it is to unite the world - it must surely be credible to the world outside the North Atlantic bubble of the United States and Western Europe.

For if it appears to be a war against a certain kind of terrorism only - the kind that attacks America and its friends - then it will look less and less like a war against terrorism and more and more like a war for American self-defence. Now that is no less legitimate a war, for manifestly the United States was attacked and has the right to self-defence, but it is not the same thing as a war against terrorism.

And we must not be surprised if much of the world - particularly parts of it that have experience of terror inflicted by America's friends - view it with suspicion and resentment.

Dual argument

Terrorism must be fought in the short and medium terms.It must be possible to denounce what happened on 11 September, to back military action to try to ensure that those who perpetrated it are brought to justice, and to try to prevent it ever occurring again, while at the same time arguing a bigger point: that in the longer term, a world in which so many people feel so dispossessed, so powerless, is not a safe world.

For security is so intimately interwoven with justice, that in a world in which so many legitimate grievances are left unresolved, we will never be delivered from the threat - and the fear - of terror.