Analysis: US war planners change tack

The opposition had said the bombing was too light

		By Jonathan Marcus BBC defence correspondent

The Pentagon has acknowledged that giant B-52 bombers have been in action "carpet bombing" front-line Taleban positions.

Carpet bombing is not a term much-loved by the military in this age of precision-guided munitions.

But the B-52 can carry a very large bomb load and, by delivering what is known as "a stick of bombs" from high altitude, it can spread the explosives in a long line over a large area.

B-52s can carry a very large bomb load

Such bombing is typically used to attack enemy ground troops dispersed in front-line positions.

It is an efficient and terrifying way to attack units in the field. The weight of the firepower damages the morale of those troops who are not killed or wounded.

The B-52's design dates back to the 1950s, though upgrades mean that it will be flying well into the second decade of the 21st century.

At full load, a B-52 can carry more than 55 100-pound bombs, though the available evidence suggests that a smaller number of heavier weapons have been employed in Afghanistan.

The aircraft are thought to be operating from the British Indian Ocean base of Diego Garcia.

This is certainly not the first time B-52s have been used in this campaign. They can also carry a variety of precision-guided munitions.

The role afforded to the Northern Alliance has been ambiguous

But their use against Taleban trenches suggests that the Americans want to inflict greater damage on Taleban forces in the field.

This, in turn, raises questions about a fundamental shift in the Pentagon's attitude towards the anti-Taleban Northern Alliance.

Until now, the role afforded to the opposition Northern Alliance in the Pentagon's thinking has been ambiguous, to say the least.

Washington regards the Northern Alliance forces as a kind of proxy army in this war which, they hope, will sweep the Taleban from power. But not just yet.

The Northern Alliance are seen as unrepresentative and unable to provide a stable future government - and Pakistan strongly opposes any long-term plan that would leave the Northern Alliance in control of Kabul.

So, up to now, the Americans have provided only limited practical support for the Northern Alliance.

They bomb some Taleban front-line positions but do nothing to alter the immediate balance of power on the ground.

Increased attacks

There is, at least, some evidence that this policy may be changing. In recent days the intensity of the attacks upon Taleban entrenchments and armour has significantly increased.

What is not clear is if this is a prelude to some concerted Northern Alliance offensive.

There are a number of problems here.

US air power can certainly soften up Taleban positions, but it is by no means certain that the US has sufficient air power, close enough to Afghanistan, to provide the sort of close air support needed to back up a major ground assault.

Morale high

The capabilities of the Northern Alliance forces themselves are also in doubt.

Morale appears high and they are clearly happy to see US bombs dropping on their Taleban enemies.

But are they capable of pressing home their attack - especially if it meets significant resistance?

All this begs the question what would happen next even if the Northern Alliance were successful?

The US probably hopes that limited gains can be made - not least to show that the campaign is moving forward - but it is not clear that the political constraints have been removed altogether.