The 9/11 attacks are apparently a milestone for the United States (US) and the world alike. Right after the 9/11 attacks, the US started a war-on-terrorism policy against al Qaida and its affiliations. The US had to change its priority because of the attacks and embarked on taking vigorous action to eradicate global terror networks. Thus, in its first year this war involved a maintained campaign against the al-Qaeda network and the termination of the Taliban regime in Afghanistan.This paper assesses the war on terror policy of the US against al-Qaeda and Taliban in Afghanistan and what went wrong there after the intervention. It also points out the miscalculations and policy deficiencies in promoting stability after the invasion.