The terrorist act of turning civilian aircraft into missiles and slamming them into the towers of the World Trade Centre in New York and the nerve centre of the US military, the Pentagon in Washington, has been compared with the Japanese attack on Pearl Harbour, 60 years earlier.

Pearl Harbour changed US attitudes to the world. September 11 changed everyone's world.

At the core of September 11 was the indiscriminate use of homicide, the killing of thousands of innocent bystanders to give expression to a fanatical point of view and to gain attention for it.

It surely succeeded in the latter, but the challenge at hand is to deny the former – the triumph of the sick philosophy of terrorism; to refuse to accept the emergence of terrorism as the 21st century's form of war.

If this battle is to be won, we, ordinary Australians and ordinary people around the world, will live our daily lives differently. This is sad, but true.

First, daily movement in travel and access to a wide variety of public buildings will soon bring security screenings, pass systems, searches of baggage and persons that will be stricter, slower and more intrusive than ever before.

Taking one's seat on an aeroplane, especially an international flight, is likely to become a two to three-hour process.

Second, just when the idea of the world as a global village was taking root – free movement of peoples across borders, reduced need for passports or visas, not to mention multiculturalism and improved tolerance among different peoples and religions – it can be expected the ethnic, religious and political activities of travellers, migrants and refugees will be investigated.

It is a bitter irony that the terrorists, whose philosophy is one of ethnic and religious intolerance, will cause us to give a new level of attention to such differences just when our whole trend was towards trying to build more tolerant communities.

The economic sphere will also be deeply affected. The trend for at least the past 20 years has been towards building a more interdependent, global economy.

But the free passage and trading of goods will now become subject to the need to deny terrorists – and countries that support them – free participation in the global economy to ensure they do not get the weapons they will use in terrorism or the money to finance their destructive activities.

The tragedy of this is that the burden of economic sanctions against countries that harbour terrorist groups will fall, largely, on innocent people who, if they had a voice, would say they preferred freedom to fanaticism.

President George W. Bush has said the US will find the murderers of September 11 and punish them and the countries that support them.

He should be believed – he means it, as he should.

If this crisis is to be contained and if the democratic countries, including Australia, are to avoid fulfilling the demonic picture painted of them by the fanatics, it will be crucial that the identification of the terrorist culprits is accurate, supported by hard evidence, and the punishment, then devised, fits the crime and is not driven by a wish for vengeance.

The structures we must then build in this changed world must include a deep agreement among nations, backed up by actions, that terrorism is unacceptable in civilised society.

Countries with important differences in outlook, culture and religion must agree that in spite of those differences, they have a common interest in ridding the world of fanaticism and terrorism.

This will call for a new level of leadership from political and religious leaders and action to ensure that fanatics in their own societies are outlawed, that the tail of bigotry does not wag the dog of society or secure relations among nations.

If these steps are not taken, if we fail to accept the change and challenge of September 11, we will suffer repetitions of it.

In the meantime, Australians – like so many others – will have to accept that innumerable aspects of their daily life will become the subject of more intrusive controls and checks.

What they should demand in return is that world leaders meet the challenge of the world that has now emerged and eliminate terrorism and the vicious prejudices that support it.