On Friday Parliament was recalled to hear the Prime Minister's statement and debate the attack on the USA. It was a sombre and serious occasion, but I was not convinced that many of my fellow MPs had completely grasped the likely long term consequences for the United Kingdom and the rest of the world. On Saturday Iain Duncan-Smith asked me to become a Conservative Spokesman on Northern Ireland. Britain's domestic experience of dealing with terrorism and its causes over 30 years became more personally relevant than ever in this global trauma.

Tuesday 11th September 2001 was a day when the course of history changed. The western world has been woken up with a brutal demonstration that we do not live in an era of permanent prosperity and security. It came at a time when the early promise of the Northern Ireland peace process seemed to be collapsing in the hatred of the Ardoyne road and in the active arms caches of the IRA.

However the 11th September outrage seems to have killed twice as many people as has been lost in 30 years of terror from Northern Ireland. Our hearts go out to all those with relatives or friends who have been lost. The scale of the carnage is so enormous that in the Reigate constituency alone too many will find themselves in this position.

In Britain just last June our election seemed to show a collapse in interest in politics. Politicians, myself included, despaired of being able to interest people in democracy anymore, the young in particular, to sustain even their basic participation by voting. Now the liberal democracies are under physical attack. Now their leaderships must motivate their populations to sustain a war on forces in the world that seek our destruction and will stop at nothing. But in Northern Ireland there is a warning for us. 30 years of expenditure of blood and treasure has sapped the mainland British will to sustain the Union according to the latest opinion survey. The citizens will to pay the price of fighting terror in a democracy is impressively high, but not infinite. President Bush must hope that he can claim victory in a timescale more adjacent to 30 weeks or at most 30 months.

But the scale of the challenge is that no democracy can allow its civilization and people to endure the catastrophe of Tuesday 11th September 2001 again. That means eliminating or at least containing the threat.

The initial response of America with our support will take the form of military action against the forces who have declared war on us. It is fairly clear who these are. They are the Islamic religious zealots, many of whom have found their way to religious schools in Pakistan and from there to Afghan military training camps. They include organisations such as Al Quaeda set up and directed by Osama bin Laden. Whilst this seems to be the one most focussed on attacking the USA, uncomfortably these groups also include the products of the Pakistani intelligence services. More ironically still many of these groups have their antecedents in the west's support for the insurgency against the Soviets in Afghanistan in the 1980s.

They have been the source of the suicidal fighters who have enabled the Taliban to succeed in achieving power in Afghanistan and have sustained the insurgency in Kashmir. It is probably no coincidence that their main enemy in Afghanistan, Ahmed Shah Massood, was assassinated by suicide bombers posing as TV reporters last week as well.

Their fanatical determination to fight and welcome death in their cause is similar to the desperation shown by the Palestinian suicide bombers attacking Israeli targets. All these groups are under suspicion and there is an element of overlap in their enmity of Israel and the USA. However I believe we must distinguish between them. Palestinian desperation is as powerful political motive for these suicidal attacks as religious fundamentalism. What marks out the terror emanating from Pakistan and Afghanistan is the extremity of the religious and cultural motivation with any rational political objective wholly secondary. Indeed our own experience in Northern Ireland with the multiple deaths of the IRA hunger strikers in the 1980s show that Islam has no monopoly on determination to die in a cause, however irrational that appears to outsiders.

But the political terrorist is also enmeshed in criminality such as the drugs trade. The IRA suspects arrested in Colombia recently shows how hydra headed the terrorist enemy is.

The democracies' campaign should have two distinct objectives. The first will be the short to medium term military one. To get inside the terror organisations and destroy or sufficiently degrade their fighting potential so as to reduce the risk of a repeat or worse of 11th September. This is likely to mean attacking the states that give them support. The second objective will be long term and more difficult. We will have to address the causes that make people prepared to fly planes into buildings and blow themselves up in an effort to kill as many other fellow human beings as well as themselves.

But then again spare a thought for our governments. Nothing is clear or straightforward. In Northern Ireland the political representatives of the IRA are now in the administration. Yet still there is no permanent renunciation of or ending of violence and intimidation. In Israel by contrast the democratic authorities have been robust if not brutal in their suppression of terror.

Indeed they have provided for the Muslim world a glaring inconsistency in the liberal democracies moral position. These are the dilemmas facing our leaders.

Democratic governments will make mistakes in trying to achieve success and our protection. They will no doubt be confused by the contradictory lessons of political and military experience. However our Government and that of President Bush deserves the support of all its citizens in the wretchedly difficult task ahead.

We face an enormous challenge to the collective will of the people of the western liberal democracies. The battle is likely to be prolonged and expensive and possibly bloody. However this war was declared on us in probably the most bloody and expensive outrage in history. Will people in the USA, most of whom don't travel outside the USA, fewer than half of whom vote in national elections and people in Britain, 41% of whom chose not to participate in their democracy in 2001, find the will to defend their civilization? If we don't, it's unlikely the rest of the liberal democracies will either. Our faith in our own political system is about to be put to the most severe test.