Crispin Black: The doubts about our mission that refuse to go away

The prevailing attitude to the counter-insurgency campaign in Afghanistan seems to reflect that of Prendergast, the clergyman who lost his faith in Evelyn Waugh's dark satire Decline and Fall. He had what he called "Doubts" about God. He was sad to have them and would rather have gone on believing. But the doubts would not go away. Most of us have Doubts about Afghanistan. Government spokesmen suggest that to have them is to give succour to the Taliban or somehow be disloyal to our troops in the field. But they won't go away.

Prendergast's doubts are in fact doubly relevant to Afghanistan. "Once granted the first step, I can see that everything else follows," he says. What he had difficulty with was not the religious structure in place but "why God had made the world at all". This accurately reflects the fault line over Afghanistan running through public opinion. The debate over the past few weeks, as mediated by most professional politicians, commentators and ex-military men, basically accepts the first step. Yes, we should be there. Yes, the grinding, gallant, sanguinary advance of our troops, ditch by ditch, along the Helmand valley is worth it – a style of warfare that would have been familiar to the last Great War soldier, Harry Patch, who died yesterday. And the whole structure appears to rest on the single judgement that attacking the Taliban in Helmand will somehow make the streets of London safer from terrorism. But in reality, outside the polite self-censorship of the chattering classes, few people buy this justification. Even Lord Malloch-Brown, who recently resigned from the Foreign Office, does not seem to believe it. He, like everyone else, knows perfectly well that the main terrorist threats to the UK emanate from Pakistan and radicalised British Pakistanis.

And if the campaign is so intimately connected to the security of the streets of London, then why are we committing only a brigade or so to the fight? Why not a division? Why not every available soldier? Why has Gordon Brown not asked the Queen to issue the Order in Council required to recall all reservists to the colours?

We are all Prendergasts now, from the Prime Minister downwards, though he certainly will not admit it. These doubts account for everything. If, as a country, we were convinced of the necessity of what British forces are trying to achieve, we would greet the news of the costs in lives and money with stoical acceptance. Is the Prime Minister such a monster that he would underfund our troops in the field in order to spend the money on "buying" votes in Labour pocket boroughs, as some seem to have suggested? Or is he just reluctant to commit further resources to a campaign enthusiastically but casually entered into by Tony Blair with little long-term thought or calculation.

Part of me wants to be there with my old regiment, the Welsh Guards, but I still have doubts. I suspect that, beneath it all, so do the higher levels of the military. Watch what the generals say on television or in the press: they "believe" or are "convinced" or "dedicated" to the mission. I can't remember anyone needing to say this about the British Army of the Rhine, or Operation Banner, the army's presence in Ulster.

The threat to our way of life from the Soviet Union was clear, and the link between bombs in Belfast and London obvious. Other interventions, such as taking back the Falkland Islands or ejecting Saddam Hussein, needed little justification and (at the time) were broadly accepted as necessary by the public.

The military historian Martin Windrow summed up the French campaign in Vietnam in his great book The Last Valley as follows: "a series of governments were believed to have let the army down; they had sent it to perform a task for which they were unable or unwilling to provide the means, and which they lacked the courage to prosecute seriously or to abandon decisively."

Let's hope that in a few years' time the same cannot be said of the UK's campaign in Afghanistan.

Crispin Black wrote 7-7: What Went Wrong? and is an associate fellow of Chatham House.