Who can we blame? There must be someone. When disaster lies all around, democracy craves a culprit, someone to carry the can. This past weekend has seen an orgy of blaming: of Boris Johnson, Joe Biden, Dominic Raab (Britain’s foreign secretary), his ambassadors, Nato and the west generally, not to mention George Bush and Tony Blair. Afghanistan was supposed to be the “good” intervention, the one that worked. Yet the “nation” we spent 20 years building has suddenly collapsed. Where are the architects? Victory has many parents, defeat is an orphan. Nothing looked as lonely this past weekend as “Afghan nation-building”. But whereas tyrants who fail can be toppled, democracy rightly diffuses responsibility. It is all very well accusing Biden or Johnson or their predecessors. We elected them. When things went well, the west trumpeted its values and patted itself on the back. It was so evidently superior. The purpose of blame is usually to avoid the repetition of the mistake. Almost unbelievably, Johnson does not think it was a mistake. He said at the weekend that the Afghan expedition was not about the Afghans but about Britain, “to protect the United Kingdom from harm”. Proof of success was that “no terrorist attack has been launched from Afghan soil” against a western country in 20 years. Nor was there any attack from Iranian or Syrian or Saudi Arabian soil, without the need to spend £37bn and cause the deaths of thousands of Afghans. Most terrorist attacks on Britain have come from within Britain, but Johnson did not mention that. What idiot intelligence chief is advising Downing Street these days, and what consolation is Johnson’s smugness to the families of thousands of dead Afghans? Britain may not be well governed at present, but it is a world-beater at blame. It screws up constantly but afterwards does the finest public inquiries. Every disaster – from Bloody Sunday to infected blood to Hillsborough to Grenfell Tower – has armies of lawyers hurled into the breach. The battalions arming themselves for Covid will now be joined by those muscling into Afghanistan. The victims can be left in their misery, but the lawyers will stagger to their bank. Everyone will declare that “lessons will be learned”. They will not if they are confined to the poor mugs who found themselves on the frontline at the end. For Britain, Afghanistan has never been anything but a neo-imperial fantasy dressed up as anti-terrorism. Vast amounts of cash were spent to prop up the occupation and convince Afghans that Nato would create a democracy proofed against resurgent Islamic fundamentalism. Britons almost universally cheered on this venture. They voted for its authors. They derided – for perfectly sound reasons – the values of its foes. They are now desperate to offload blame for failure. But blame lies with western democracy at its most arrogant and interventionist. Blaming Biden and Johnson for not concealing it is absurd. Simon Jenkins is a Guardian columnist The fall of Afghanistan: join a Guardian Live online event with our journalists Emma Graham-Harrison, Peter Beaumont and Julian Borger analysing the latest developments. Monday 6 September at 7pm BST. Book your tickets here. All profits will be donated to relevant charities.