While earlier reports made by the big four US intelligence agencies all acknowledged that Afghanistan would eventually fall to the Taliban, the swiftness by which the takeover occurred was not predicted by any of them.
Months prior to the collapse of order in Afghanistan, the US' leading intelligence agencies compiled reports detailing their thoughts on the future of the war-torn nation. The reports date back to April 13 of last year when, following then president Trump's decision to withdraw troops by May 2021, the Central Intelligence Agency released their prediction that the Afghan government would fall after US funding and soldiers had left.
According to the Wall Street Journal, this idea that the Taliban would take over only after the US withdrew from Afghanistan was echoed in nearly every report, from April 2020 all the way up to July 2021.
Following President Biden's April declaration of a new troop pullout deadline, the CIA in May predicted that Afghanistan would fall by the end of the year, while the Defense Intelligence Agency in June suggested the Taliban would "pursue an incremental strategy of isolating rural areas from Kabul over the next 12 months."
While the timeline differed slightly, not one intelligence report anticipated the possibility of Kabul falling to the Taliban in August, and certainly not while US troops were still on the ground.
According to the Wall Street Journal, a July 2021 DIA report shows that even Afghan leaders themselves thought their government would hold at least Kabul in September or October.
The Taliban took over the capital on August 15, 2021 and quickly become the sole governing power of the entire country.