Tony Blair and George W Bush have a lot to answer for.

From the moment that the invasion happened, there were only two possible outcomes: perpetual military occupation or the Taliban retaking the country. This is because the Afghan people (whatever their views on the Taliban) never ever supported the military invasion by foreign powers. Look at the pitiful resistance given by the heavily funded government army. Also look at how the Taliban managed to survive any military defeats by getting support from the rural Afghan populations. You can win a conflict by conventional means but you can never win consent to rule in this way.

This is not WW2: in which the population of a modern Western country accepted military defeat and preferred subjugation by Western powers to the alternative, which was rule by Stalin's USSR. The process was aided by massive national guilt for the holocaust, a willingness to build a new country and a desire to eventually reunite with East Germany. That situation was exceptional is no analagy for the war against the Taliban.

You can't invade a country, kill lots of people and then expect a domestic populations to support you. Vietnam does work as an analogy, as does Iraq.

The war never had a true humanitarian aim anyway. Nor was it ever really about defeating terrorism. There were and are plenty of other abysmal regimes across the globe and Bin Laden got killed (in Pakistan) years ago. It was a war fought for the same reasons most wars have always been fought: over power and resources. That it failed so abysmally on its own terms does not mean that those terms were ever good.

Biden will get blamed for this but to criticise him here misses the pount: this was always going to happen. It could have been ten years later or ten years earlier but the awful results woukd still have been the same.