Can the Americans win a land war in Afghanistan?

"We do deserts, we don't do mountains," said Colin Powell when he was chairman of the Joint Chiefs of Staff as the Balkans' conflict erupted. Now, General Powell is US Secretary of State and probably has no choice in the matter. But working out whether America can win this fight is complex; it all depends, as Bill Clinton might have said, on what you mean by "beat".

The mountains are where the bases of Al-Qa'eda, the organisation that the US blames for the attacks on New York and Washington, can be found. But US forces have never planned for a conflict like this. Their strength lies in large-scale land warfare; they trained to fight on the north European plain, in Korea and on the Arabian peninsula. Victory in the Gulf War came about through massive armoured capability and huge air power.

Now, they can forget the tanks. There is a role for light armoured vehicles in Afghanistan, but as the Russians found, lengthy armoured convoys are an invitation to attack by guerrillas with rocket-propelled grenades.

Victory for the US in Afghanistan – if that is where it decides to go – will not mean victory over the Afghan nation or their armed forces. Unlike previous invaders, such as the British and Russians, the US does not want to occupy Afghanistan or even dominate it. It wants to locate those it holds responsible for the New York and Washington attacks, and either capture or kill them.

This is a very tall order. Finding them is tough. It will mean using intelligence from US satellites and resources, but also from others in the region – Pakistan, Saudi Arabia, Russia, Iran. But all of these will want to make sure that American ambitions in Afghanistan do not endure beyond the mission.

The next step could be an air attack to pin down suspectsand prepare for assault – but even precision munitions and heavy bombing might not do the job. The targets are spread out and many are highly mobile.

The expectation seems to be that the US will use regional bases as a temporary refuge. Securing this will be difficult. The Taliban have Scud missiles, and Stinger anti-aircraft missiles, so the risks are high. In a direct firefight between US troops and the Taliban or Al-Qa'eda, the US would probably win. But one of the first principles of guerrilla warfare is that a direct firefight is not what they will get.