Whatever happened to the war? You know the one. The west has been fighting it for a decade. The costs run to a trillion dollars plus. Tens of thousands of soldiers and civilians have been wounded or killed. The conflict was once an existential test of the Nato alliance. Now, the US and its allies are scampering for the exit. They probably do not have much choice about leaving. But, please, not like this.

We live in an age of short attention spans. The west’s fight against the Taliban in Afghanistan is no longer headline news. Politicians, generals, diplomats and much of the media are joined in an unspoken conspiracy that says out of sight, out of mind. This script declares the International Security and Assistance Force will leave behind a stable and sustainable Afghan government when the troops head home next year. Security will belong to the Afghan National Army. The official history can record, as George W Bush said of Iraq, that this was another “mission accomplished”.

The tellers of this tall story privately admit deep embarrassment at the duplicity. What is planned is a retreat. There are indeed scenarios under which Afghanistan could hold together afterwards, but they stretch the most elastic limits of plausibility. In its latest report to Congress, even the Pentagon points up the Taliban’s resilience. Western forces, it admits, will long be needed to prevent a collapse of the Afghan government.