Timothy Garden: Air strikes will not win this war - so let's send in the ground troops

'Air power can only play a minor part. The smartest bomb cannot seek out individuals by name'

Western publics have grown used over the past decade to the launch of air strikes as the signal that crisis has moved to conflict. The Gulf War changed the nature of warfare. A prolonged air campaign won the battle before armies engaged on the ground. The Bosnian conflict of the mid 1990s appeared to be resolved only after Nato used its air power to bring the warring factions to the negotiating table.

In Kosovo in 1999, the air campaign was conducted under extraordinarily restrictive rules. Not only were there to be no casualties to the Nato air crew, but refugees were to be protected and Serbian deaths and injuries minimised. Arguments continue as to which factors were key in convincing Slobodan Milosevic to negotiate a settlement; but to the public, air power had chalked up another relatively bloodless triumph.

Computer games and futuristic war films have bred a generation of aerospace advocates. The belief grows that smart munitions can deliver whenever diplomacy fails.

Senior military officers, diplomats and government officials are only too aware of the limits of what can be achieved by purely military means. Air attacks can bring pressure to bear on adversaries to make them negotiate. They can change the military balance of power, so that a ground operation becomes much easier. In every case the air campaign has to be structured to promote strategic aims.

In the Gulf War, the aim was to remove the Iraqi occupation forces from Kuwait. This was a classic conventional battle for territory, where modern air weapons could make the regaining of lost territory much easier. In Bosnia, the use of very limited air strikes was only one element in a complex political and military situation. The agreement reached at Dayton, Ohio was more a result of a combination of diplomatic effort and realities on the ground than the effect of air strikes.

In Kosovo, the air campaign showed the determination of the members of the Nato alliance, but finding the appropriate sets of targets for a humanitarian war was problematic. Finally diplomacy, helped by air power, triumphed in bringing about a negotiated settlement. All of this suggests that air operations in Afghanistan can only be peripheral to the overall campaign against terrorism.

The strategic aim of the broad coalition of nations formed since 11 September is the elimination of international terrorism. There are a number of subsidiary tasks which support that aim. The highest priority must be given to reducing the immediate threat of follow-on attacks by the terrorists. Atrocities will be undertaken by those who passed through the bin Laden training camps long ago. Reduction of immediate risk comes from protective measures, such as enhanced airport security, and from the detecting and detaining of sleeper terrorists.

The front-line forces of this campaign are the police and intelligence services. Future long-term threats come from those who train, arm and fund terrorism. States can be deterred from providing support to terrorism through economic, political, diplomatic and military measures. Non-state terror organisations, particularly those with a suicide culture, are more problematic when it comes to deterrence.

Counter-terrorism needs good intelligence to find the vulnerabilities in such organisations. The military can exploit that intelligence to attack the vulnerable points, and to remove the support infrastructure. This is a quite different military activity from trying to bring about an agreed settlement to some dispute. There is no table where the perpetrators of the attacks on the World Trade Centre and the Pentagon can be brought to sit round and agree some diplomatic settlement.

So military air power over Afghanistan can only play a minor, if highly visible, part in the grand strategy. The attack on the al-Qa'ida training camps will delay the training of new terrorists, and it might kill those who fail to take shelter. But the smartest bomb cannot seek out individuals by name.

What is needed is a very fast cycle of operations between intelligence gathering, mission tasking and missile firing. This is made easier by eliminating the Taliban air defence systems to allow reconnaissance and intelligence patrols. A mistake by the terrorist leadership may lead to an attack opportunity using the directed firepower of the low-flying AC130 aircraft guns. But few airmen expect to be that lucky. Finding individuals is best done by a ground-based search party, delivered and protected by air power.

The attacks on the Taliban government infrastructure are more recognisable as part of a classic air campaign. While they might coerce the leadership to hand over Osama bin Laden, few believe that the Taliban will deliver their main protector. The air campaign has therefore a secondary aim: to topple a regime that supports terror. However, this begs the question of what is to follow. Allowing the Northern Alliance's ragged army to sweep into Kabul is unlikely to be a recipe for peace, harmony and good governance. Whatever form of shared administration that follows the end of the Taliban government will require a strong international military force to ensure the rule of law.

We have grown used to fielding troops to promote stability in the Balkans. It is not too early to start putting in hand the arrangements for a multinational peacekeeping force for Afghanistan. All those nations who have expressed support for the air campaign need to consider what they are going to contribute to the post-conflict rebuilding of Afghanistan.

The air campaign will continue until the terrorist training camps are exhausted. Air patrols for intelligence and reconnaissance will need to continue for many months. When the Taliban take to the hills, the time will have come to move from air operations to the far more difficult ground operation. With good governance, the long-term campaign for the hearts and minds of the Afghan people can begin.

Humanitarian aid and enforcement of the rule of law are just the beginning. Terrorism is eliminated by removing the injustices which generate its support.

Air Marshal Sir Timothy Garden is visiting professor at the Centre for Defence Studies, King's College, London