Tony Blair is right - this is a new war and we must accept new ways of fighting it

The elimination of failed states will not eliminate all terrorism. Terror is the cancer of idealism

It seemed an extraordinary choice of word, yet the more one thought about it the more appropriate it became. When King Juan Carlos addressed the Spaniards - how fortunate a nation is to have a monarchy - he reminded them that they were a strong people. He also told them that they were serene.

It seemed an extraordinary choice of word, yet the more one thought about it the more appropriate it became. When King Juan Carlos addressed the Spaniards - how fortunate a nation is to have a monarchy - he reminded them that they were a strong people. He also told them that they were serene.

Although this would have come as startling news to almost all his subjects, who were feeling anything but serene, the King was right. Grief and rage may have their hour, but if the terrorists are to suffer the moral defeat that they deserve, serenity and its close kinsman stoicism must ultimately prevail. Terrorism shall have no dominion.

Others ought to note the King's statement for future use. There will be more Madrids and the next one could occur in London. In ways that we do not and should not know about we have already benefited from the intelligence services' vigilance. We have probably also been lucky. Luck runs out. Vigilance is not infallible. It will be astonishing if we British too are not required to draw upon our reserves of stoicism and serenity.

Clearly, serenity is not enough. We cannot wait to be attacked; there must be counter-measures. But even traditional methods of counter-terrorism, vital though they be, are not enough. There are moral and geopolitical issues that need to be addressed, for they help to shape the context in which terrorism must be confronted.

Here it is unfortunate that we have a tarnished Government with so many ministers who have such difficulty in telling the truth. On two crucial issues, whatever the degree of public scepticism, the Government is right. When dealing with terrorism law must be the buttress of order, not a means to subvert it. In desperate international cases pre-emptive war is necessary to avert greater dangers.

In its infancy law was the handmaiden of order. The earliest lawyers merely codified what the ruler's right arm had already accomplished. With civilisation came rights. Law evolved. Instead of merely being part of the state's teeth it could also enable the citizen to bite back.

The paradox of modern law, simultaneously enforcing and limiting the state's jurisdiction, is the foundation of our criminal procedure, as can be witnessed daily in the courts. The scales that balance the rights of the accused and the requirements of law enforcement have been set in such a way that large numbers of criminals go free. As the crime figures demonstrate there is a cost, but we tolerate the imperfections because we accept that our freedoms and rights could only be protected if the man in the dock also enjoyed them.

When it comes to terrorism the scales must be re-set. Freedom: those Madrid commuters enjoyed the freedom of beasts grazing peacefully as the lorry slipped into the farmyard to take them to the slaughterhouse. Rights: only one right, the right to live, is more vital than the right to order. In its absence, no right, least of all the right to live, can be securely enjoyed.

Pre-emptive action will also be a permanent feature of a new world order. We must have the courage and the political stamina to insist that international law, if it exists at all, cannot be allowed to subvert the drive for global order. We cannot allow vital national interests to be compromised by a coalition of the dictatorships taking their turn on the Security Council, anti-Western lawyers and Jacques Chirac.

In his recent speech on the Iraq war and the continuing terrorist threat, Tony Blair expressed his views in slightly more idealistic terms than I am using. His idealism was justified, although it would have been better if he had excised his references to the Treaty of Westphalia, which sounded pretentious and insincere. The Prime Minister's argument that the nation-state order inaugurated by Westphalia had now been surpassed was clearly based on an aide's précis of Philip Bobbitt's Shield of Achilles. Everyone knows that Blair himself has never given 45 minutes of thought to the Treaty of Westphalia.

Mr Blair would have been wiser to rest his argument on current realities. A world in which failed states swiftly turn into rogue states is a world that can no longer dare to tolerate failed states. At that point tough-mindedness and idealism become indistinguishable, as in George Bush's foreign policy.

Tony Blair was drawn to the idealism, hence another paradox: the one that will define his premiership and explain its failure. It is bizarre that a Prime Minister who evoked idealism in numerous inappropriate contexts should prove incapable of exercising it when it was not only necessary but supremely justified.

The great political, strategic and moral challenge that faces the West is to make the rest of the world safe enough for us to enjoy freedom and prosperity. We can only succeed by helping the rest of the world to become prosperous and free. That is a task which should unite right and left; exactly the sort of rhetorical territory in which Tony Blair ought to feel most at home. Yet he flunked it: he is not a man for challenges.

The elimination of failed states will not eliminate all terrorism. Terror is the cancer of idealism. It occurs when the healthy political cells, which are to be found in every radical-minded, generously inclined youngster, turn malignant.

It is natural for the intellectual young to be impatient of constraint, contemptuous of partial success, dismissive of the legacy of the past, infinitely naive and credulous about the glories of change. In most cases this is no more than a phase - although it is one that Tony Blair has not outgrown in his dealing with the British constitution.

But at a young age most recognise that however unaesthetic the bourgeois order may be, however far it falls short of the efflorescence of emancipation dreamt of during the Enlightenment, it is vastly preferable to chaos.

Not all the young, however, learn to compromise with reality. In extreme cases, especially when inflamed by nationalism and a sense of historic injustice, idealism can turn into terrorism. The idealists come to believe that most past history and most present-day people are tinder, to be expended without limit or mercy when feeding the furnaces in which a better future can be forged. Burke, Conrad and Dostoevsky understood this, as at moments, did Yeats: "Too long a sacrifice can make a stone of the heart." One hopes that they are all required reading for the new recruits to the secret services.

I had always been inclined to believe that terrorism was not a real academic subject. Now I am not so sure. It is certainly true that any student who chooses to specialise in understanding terrorism will not lack employment. The rest of us can only hope that there are enough good students, and that they enjoy an unusual amount of luck.