But the key question is this: what are our servicemen dying for? There are glib answers to that: bringing democracy and development to Afghanistan, supporting the government of President Hamid Karzai in its attempt to establish order in the country, fighting the Taliban and preventing the further spread of radical Islam into Pakistan.
But do these answers stand up to close analysis?
There has been too easy an acceptance of the lazy notion that the war in Afghanistan is the 'good' war, while the war in Iraq is the 'bad' war, the blunder. The origins of this view are not irrational. There was a logic to attacking Afghanistan after 9/11.
Afghanistan was indeed the headquarters of Osama Bin Laden and his organisation, who had been installed and financed there by the CIA to fight the Soviets from 1979 until 1989. By comparison, the attack on Iraq ? which was an enemy of Al Qaeda and no threat to us ? was plainly irrational in terms of the official justification.
So the attack on Afghanistan has enjoyed a much greater sense of public legitimacy. But the operation to remove Bin Laden was one thing. Six years of occupation are clearly another.
Head of the Afghan armed forces: General Abdul Rashid Dostrum
Few seem to turn a hair at the officially expressed view that our occupation of Iraq may last for decades.
Afghanistan was not militarily winnable by the British Empire at the height of its supremacy. It was not winnable by Darius or Alexander, by Shah, Tsar or Great Moghul. It could not be subdued by 240,000 Soviet troops. But what, precisely, are we trying to win?
In six years, the occupation has wrought one massive transformation in Afghanistan, a development so huge that it has increased Afghan GDP by 66 per cent and constitutes 40 per cent of the entire economy. That is a startling achievement, by any standards. Yet we are not trumpeting it. Why not?