Strong Loyalties, Ancient Hatreds
Good Time magazine article on tribal warfare in Afghanistan. Establishing any form of stable government there is going to be difficult.
As an aside, there's an interesting explaination in the article about why Pakistan let so many of its people go fight for the Taliban. It appears they let them go to clean out the gene pool. Makes sense to me - let you hard core rabble rousers go to their early demise and end up with a more stable population.