Leading article: A blow to a new Afghan strategy

Afghanistan has witnessed one of its fiercest battles since the fall of the Taliban eight years ago. At the weekend in Nuristan, a province that lies on the eastern border with Pakistan, hundreds of militants attacked a US military base with machine guns and mortars. Eight American troops were killed.

Such heavy casualties could not have come at a more sensitive time. American public opinion now appears to have turned against a continuation of the mission in Afghanistan. It is a similar tale in Britain and much of Europe. And the widespread allegations of vote-rigging on behalf of Hamid Karzai in August's presidential election have left the Kabul government perilously lacking in legitimacy. The pressure on America and Nato to scale down the Afghan mission is growing. Rising military casualties are likely to double it.

There is a bitter irony here for those strategists who want to refocus the military effort in Afghanistan. The US army had already planned to pull troops from isolated and vulnerable bases like the one in Nuristan and send them, instead, to important population centres threatened by the Taliban.

The US commander in Afghanistan, General Stanley McChrystal, has long advocated a greater emphasis on protecting Afghan civilians than killing insurgents. This is the very sort of battle that General McChrystal did not want his troops to be fighting.

The general's argument is that, to accomplish this necessary shift, many more troops are needed. This is a plea that was echoed at the weekend by General Sir David Richards, the new head of the British Army.

But will they get them? President Obama is considering his general's request. The US president says he needs to be convinced the strategy is right before he sends more troops to Afghanistan. And other Nato members are unlikely to increase their own commitments without a clear signal of intent from the US.

These are uncertain days for the Afghan mission. General McChrystal has a coherent strategy for stabilising Afghanistan. The problem is that with every perception of a battle lost, like the one in Nuristan, the likelihood of him being given an opportunity to execute it grows ever slimmer.