**Invading Afghanistan [initially had mass public support] (https://www.pewresearch.org/politics/2021/09/02/two-decades-later-the-enduring-legacy-of-9-11/) as an act of retribution to pursue al-Qaeda after the 9/11 attacks. But it's clear that the US's military presence was not fully thought through & the lives lost and economic damage that ensued in Afghanistan ended up hugely outweighing that of 9/11.** - The 2002 invasion of Afghanistan was very much framed as a response to [al-Qaeda's involvement in the 9/11 attacks] (https://www.911memorial.org/911-faqs). While it's easy to say that the invasion 'shouldn't have happened', it's also easy to see why it did. But the fact is — the Afghans themselves weren't involved with the attacks, and they have [suffered immense casualties and economic losses] (https://apnews.com/article/middle-east-business-afghanistan-43d8f53b35e80ec18c130cd683e1a38f) as a result of the US presence. - It's arguable that the US intervention in Afghanistan — which involved the killing of Osama bin Laden in 2011 — is what has prevented another terrorist attack like 9/11 from taking place in the West. But the self-interested motivations of the US in Afghanistan meant that once this post-9/11 fear and anger had died down, they always [had one foot out of the door] (https://www.theatlantic.com/ideas/archive/2021/08/plywood-army-afghanistan/619779/). This, in turn, failed to defeat or entirely eliminate support for the Taliban (from both Afghans and neighbouring Pakistan) because once the US withdrew, as they frequently planned to, Pakistanis and Afghans knew they would have to contend with these powerful Taliban forces. - This is why — when Biden finally withdrew all US troops from the country this year, while many were shocked at [how quickly the Taliban were able to take control] (https://www.bbc.co.uk/news/world-asia-49192495), it is not surprising that the group have been able to do so so quickly. Once troops were stationed in Afghanistan, the US just didn't know how to remove them with what could be considered success — so, ultimately, they opted for a quick extrication, followed by what is widely viewed as a highly unacceptable outcome.