Leading article: Wise words on containing the Islamist threat

Some are bound to criticise the new Chief of the Defence Staff, General Sir David Richards, for daring to say that the West cannot defeat al-Qa'ida but should realistically aim at some form of containment strategy, which may have to last for decades.

We congratulate him for injecting a note of common sense into an often-polarised discussion about the right response of the world's democracies towards the threat posed by Islamist militants.

The General is right to downplay the usefulness of comparing a struggle against a highly dispersed worldwide movement to a conventional war "in which defeat or victory is very clear-cut and is symbolised by troops marching into another nation's capital".

He is also right to argue that promoting education, prosperity and democracy in countries most at risk from subversion is the best way to immunise people over the long term against the virus of radical Islamism.

The General's remarks are particularly appropriate to the conflict in Afghanistan. On Remembrance Sunday, alongside the other war dead, the nation honoured the 343 British soldiers who have died in a decade-long fight against the warriors of the Taliban.

They did not necessarily die in vain. But had we not allowed ourselves to become sucked into the war in Iraq, it is clear that Britain and its Nato allies might have achieved something much more durable in Afghanistan in terms of nation-building and establishing security within the country and beyond.

Instead, when we cease combat operations in Afghanistan, which we are supposed to do in 2014-15, we are likely to leave behind a country that is still an economic and infrastructural shambles, as well as hopelessly corrupt – good conditions for the Islamists to sow their message of hatred for the West.

The lessons of what went wrong in Afghanistan needed to be absorbed before we again dispatch soldiers abroad to contain a terrorist threat. Already, shrill voices are calling for some form of Western military intervention in unstable, troubled Yemen. They should be resisted. Aid, not raids, is our best hope.