In war, the moral is to the physical as three to one - Napoleon

The US administration has expressed surprise in recent days at the tenacity of the Taliban regime to date. The Taliban have lost no significant ground to the Northern Alliance, sometimes called the United Front, and have scored a number of major propaganda victories arising from civilian casualties during the US and British air campaign.

Despite the aerial bombardment, and despite renewed attacks by the Alliance, the Taliban have held key positions near Mazar-e-Sharif, Herat, Kunduz and Kabul. This has forced US Secretary of Defence Donald Rumsfeld to concede this week that in relation to the US military plan: "The pieces are being worked on, but it would be premature to say they're falling into place". It has also been admitted that Osama bin Laden might never be brought to justice.

What started out ostensibly as a simple, surgical operation to rid Afghanistan of the Taliban and al-Qaeda has metamorphosed into what will become a more protracted and complex military intervention. The problems for the US military are the same as those faced by the Soviet Union during its occupation of Afghanistan.

During the Soviet occupation, the Russians employed classic conventional tactics to deal with the mujahedeen. This involved committing 100,000 Soviet troops to the region in static formations designed to hold towns and cities and to dominate key terrain. Unfortunately for the Soviet Union, the complex geographical topography of Afghanistan and an ancient culture of resistance neutralised this approach. The Soviets then tried to eliminate the mujahedeen's civilian support by bombing and depopulating rural areas. This tactic resulted in a massive flight from the countryside with 2.8 million Afghans fleeing to Pakistan. This also had the antithetical effect of heightening support for the mujahedeen to fanatical levels.

Afghanistan quickly became the Soviet Union's Vietnam - a graveyard for Russian conscripts. Like the US in Vietnam, the Soviets attempted a last-ditch effort to salvage victory from defeat by installing a proxy government in Kabul. Led by the ill-fated Mohammed Najibullah, the country had a short history as a client state. It finally succumbed to the mujahedeen in 1992 who declared Afghanistan an Islamic Republic. Despite air superiority, sustained aerial bombing, superior numbers and equipment levels, the Soviets failed to hold ground and failed to defeat Afghan fighters. It is a scenario that sounds uncomfortably familiar today.

Contrary to popular belief and much Western propaganda, the Taliban are reasonably well armed for the ground campaign that lies ahead. At present, the Taliban has approximately 45,000 highly motivated troops at its disposal. They are armed with conventional infantry weapons, mainly Kalashnikov assault rifles, rocket-propelled grenades (RPGs), anti-armour weapons and infantry mortars.

Prior to the air campaign, the Taliban also had approximately 100 main battle tanks, mostly Soviet T55s and T62s, and around 250 armoured fighting vehicles with over 200 fully operational artillery pieces including truck-mounted multi-launch rocket systems.

Many of these assets will have been destroyed in the air attacks, but one thing is certain, morale and the motivation to fight appear to have survived. This is due in no small part to the philosophy and psychological make-up of the Taliban military.

Consisting in the main of former students of Madrassas or religious schools, the ideological core of the Taliban is well educated and highly motivated. This ideological core is complemented by thousands of seasoned mujahedeen fighters and fanatical jihadi or holy warriors. Supported also by former officers of the pre-1992 Afghan army, the Taliban represents a force combining hardened combat veterans and religiously motivated ideologues. These factors, those that constitute the will to engage and close with the enemy, are recognised in military academies around the world as crucial to success on the battlefield.

The Taliban have proved themselves in ground combat against the Northern Alliance in recent years. Jane's Defence, the international military journal, has noted Taliban prowess on the battlefield. It lists among their attributes, "surprise, mobility, speed, impressive logistics and highly efficient command, control, communications and intelligence characteristics".

Despite the air campaign, these characteristics, including the simple communications networks required for fluid formations, are apparently intact. It has been proven over and over again, that with carefully planned concealment, innovative deployment and by simply digging in, military formations can survive to fight after massive and sustained artillery and aerial bombardment.

Given their background and experience in combat and given their particular mix of religious fanaticism and unit cohesion, it comes as no surprise to learn that the Taliban continue to resist US and British attempts to collapse their regime.

Jane's Defence also notes the skilful manner in which the Taliban use customary bribes to cement alliances and appease enemy commanders. This aspect of Afghan military culture - a pragmatic approach to loyalties - requires a degree of sophistication, timing and diplomacy that depends on local knowledge. As has been demonstrated by the support given to the Northern Alliance, this is a tactic that is being employed by the Americans. The US and British will continue to provide close air support to the Northern Alliance in their attacks on Taliban positions in north western Afghanistan and around Mazar-e-Sharif, Kundez, Bagram and Kabul. They will also continue to mount special forces attacks on sensitive targets - pouring more petrol on the fires of Islamic fundamentalism.

Meanwhile, the Taliban will go to ground among the civilian population and will locate equipment near mosques in order to maximise psychological and propaganda values. The US and British aim of securing a decisive military victory before winter or of capturing a highly placed terrorist suspect now seem remote.

Like Napoleon at the gates of Moscow, they must pause to consider those two factors that provide the enemy with advantage - moral high ground and the weather.

The language of state now speaks of a longer war. Like many other wars before this, it seems unlikely that the troops will be home before Christmas.

Tom Clonan is a former Army Captain who lectures in the Political Economy of Communications in the Institute of Technology, Tallaght