What did Washington warn about in his farewell address? The advice is a foundation piece, not a period piece.
You understand that Karzai was Pashtun? There were stories that his brother was involved in a lot of graft. Many Taliban were also Pashtun as were their enemies. I had been following the activities of Massoud and the Northern Alliance and was shocked when he was assassinated by al qaeda probably as part of bin Laden’s 9/11 attack which happened 2 days later. I have always wondered how Afghanistan would have turned out if he were not killed? No Karzai, less corruption, fewer US and other foreign troops involved, including my son in 2006 and 2013? The second link lists the various allied warlords, their ethnicity, etc. Also described is how a number of countries and especially Pakistan supported one group against others in an effort to have more influence in the country.
https://en.wikipedia.org/wiki/Northern_Alliance