What frequently gets lost in these discussions is that we are way too focused on the US element of it. There was an article today that talked about how the Taliban had retaken Kabul "20 years after US troops had driven them off." That is fucking nonsense. US troops didn't invade Afghanistan. US troops didn't drive the Taliban out of Kabul. Does anyone remember the Northern Alliance? They did the heavy lifting. We supplied them and bombed the shit out of their adversaries, but we had a relatively trivial ground force at the time, fewer than 300 troops on the ground, per Bob Woodward's Bush at War.
Why is that important? Because if you are going to talk about the success of the Taliban you should probably asked what they hell happened to their main opposition, the opposition which prevented them controlling all of the country even prior to 9/11, prior to the US giving them anything.
Well, perhaps instead of worrying about which US President to blame, we should discuss the Afghani President and how he fucked up support from the Northern Alliance factions.
From an WaPo article a couple of weeks ago.
Full article in the spoiler.
TL, DR: In 2014, the Presidential race was between Ghani (Pashtun) and Abdullah (supported by the North). Ghani won a tight race. He then started undermining his opponents, including firing a popular governor in the North, replacing him with a Southerner. In the attempt to consolidate his control of a US-propped up government, he inadvertently undermined and alienated the significant factions who were otherwise inclined to oppose the Taliban. Now he is the President of jack shit. So, when assigning blame, let's just all agree to say "fuck President Ghani" before worrying about Trump or Biden. And if there is a lesson there for America, it's that power over the government is pointless if the country goes to shit.