11th September this year is the twenty year anniversary of 9/11. It is now obvious that Biden decided he wanted some nice headlines where he could boast, on the big day, that the US was out of Afghanistan.
He could have chosen to withdraw his troops this winter, after "fighting season" was over, when all the Taliban men would be back in their villages and so wouldn't be available overrun the cities, and Kabul in particular. Biden was advised to do that, in fact. But that would have meant that the US wasn't out by September 11...
Why choose August 31t as his deadline to be out? Because of 9/11! Otherwise the end of August is a totally spurious timeline.
It's a shameful mess, all because Biden wanted some headlines and a legacy. Well he got that...