So how is this a metaphor for the US response? There will be a US counter-strike. It will be tough, hard, deadly, but it is absolutely vital that it hit the right targets.

I believe the US will do this. Any indiscriminate response against Islamic targets in the Middle East would produce what the terrorists almost certainly want: a sense of the US versus Islam, or at least Middle East Islam.

Apart from the "prestige" of having hit the US so hard, what the terrorists probably want is a polarisation between the US and Middle East Islam. This would put pressure above all on moderate Middle East regimes, which enjoy strategic relationships with Washington, especially Egypt, Jordan and Saudi Arabia.

This, the greatest single co-ordinated terrorist attack in modern times, will have vast and profound consequences which it is still too early to discern.

But some forthcoming developments in the US are obvious.

There will be an immediate, huge increase in the legitimacy of the Bush presidency. Just forget altogether any ongoing debate about who won the election, whether Bush has a mandate, and so on. Americans will rally round the commander-in-chief.

There will likely be a big increase in the US military budget. Congress had recently tried to trim the military budget. Forget that. US forces will get anything they want and congressmen, quite properly, will compete with each other to be supportive of the military.

There will also certainly be a big increase in the budget for missile defence. This terrorist attack did not involve missiles. But the central proposition of the Bush administration has been that in the post-Cold War era the US will almost certainly not be challenged in conventional warfare, but is extremely vulnerable to unconventional attack by unconventional weapons used perhaps by non-state actors – that is, terrorists.

All defensive systems, from missile defence to anthrax vaccines, will get big funding boosts. So too will the intelligence agencies, from the FBI to the CIA.

This may presage broader social changes. Since the latter stages of the Cold War, Americans have enjoyed a broadly relaxed approach to security, what the boffins call a low-salience threat environment. This terrorist outrage could well mean a return to a high-salience security environment, with accompanying social changes.

The effect on the multilateral system will be both positive and negative. Forget any aspect of multilateralism – from the International Criminal Court to the Anti-Ballistic Missile Treaty – that imposes any constraint on the US ability to defend itself, or to find and kill its enemies. Don't even bother to make the argument. The Americans won't be interested.

On the other hand, this terrible tragedy offers the Bush administration the clear opportunity to regain complete global leadership. Every civilised nation is scared of and vulnerable to terrorism. International co-operation will be essential to combating it, just as it was in the 1970s. The US must take a lead here but it will have an overwhelming incentive to bring others on board. And many nations will be receptive to US leadership because they will want US help – logistic, financial, intelligence – in their battles against terrorism.

There will be a huge increase in popular US support for Israel, which bears the brunt of suicide bombings, albeit on an altogether different scale, seemingly every day. At the same time it is probably true that anything Israel now does which it describes as anti-terrorist will win support from the US.

Washington will also intensify its intelligence co-operation with Israel and its own intelligence efforts throughout the Middle East. These attacks will re-emphasise the importance of human intelligence to complement the satellite and signals intelligence at which the US excels. After all, you cannot detect with satellites a handful of men armed with cardboard cutters.

There will also be intense new pressure on rogue states that are seen to support terrorism. Renewed military actions against Iraq in the relatively near future seem highly likely.

Pakistan is the most accessible state with the greatest influence on the Taliban in Afghanistan. It is the Taliban who shelter arch-terrorist Osama bin Laden, and it is Afghanistan where Arab Islamic radicals have been gathering in recent months, and where terrorists for deployment in Kashmir base themselves.

Pakistan is a threshold failed state and a threshold rogue state. Washington can be expected to exert massive pressure on Pakistan to abandon its support of the Taliban and its support of terrorism in Kashmir and elsewhere. Already the State Department and the CIA have been conducting a review of policy towards Pakistan and Afghanistan for some months. That will now have infinitely higher priority.