The 10th Mountain Division has been to Afghanistan four times since 2001 and twice to Iraq. It is common to meet senior NCOs and captains with three combat tours behind them, an experience unmatched by any generation of US soldiers since Vietnam.

But that experience comes at a cost. British soldiers do six-month tours with 18 months off. America’s overstretched soldiers have been doing 12-month tours — and, in the case of 10th Mountain, a 15-month extended tour in 2006-07 — followed by nine months off. When soldiers talk about soaring rates of family breakdown, suicide and PTSD, there is no doubt that they describe a growing problem across the whole US military force.

It is harder to judge whether the issues confronting the 10th Mountain units in Wardak reflect a wider malaise. They are nearing the end of a long, frustrating year of being hit every day by an unseen enemy while trying to protect a sullen and apparently ungrateful population. This summer Wardak has been the pilot for a programme designed to replicate the sort of local militia groups that the Americans successfully mobilised for the “Sons of Iraq” programme, when Sunni fighters changed sides and turned on al-Qaeda. But even by Afghan standards Wardak is riven with factions and there has been little sign of progress.

In June General Stanley McChrystal, the commander of Nato forces, issued a new edict further restricting the circumstances in which American troops could use force against the Taleban. It is designed to guard against civilian casualties — but it is no surprise to hear that the soldiers do not like it.

To add to their displeasure one of their supposed allies in the Afghan police turned round and shot three of their friends dead last week.

As their commander says, counter-insurgency is a marathon in which individual rotations of soldiers may not lead to discernible progress during their tour. And it is worth noting that since extra US forces were deployed in Logar and Wardak, security further north in Kabul has improved.

There is no sign that the US military believes morale is dropping to a point where there is a threat that its soldiers will stop fighting, as happened in Vietnam. However, soldiers are highly sensitive to any loss of support for what they are doing, from either politicians or the general public.

What has sustained the US military and public since the September 11 attacks is the iron conviction that they are engaged in a just war against an enemy that directly attacked —and continues to threaten — their nation (even if many would argue that in the case of Iraq it was a mistaken belief). As a result America, a nation previously averse to the sight of body bags coming home, has so far been willing to accept the butcher’s bill from Iraq and Afghanistan.

Is that conviction now beginning to ebb away?

The apparent dithering of the Obama Administration and other Western governments on future strategy for Afghanistan in recent months sends a poor message. What is the mission? Why are we here? In this respect the soldiers in Wardak feel the same way that much of the British public does.

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