In this thesis, I am looking for the answer to the question: To what an extent did the United States intervention in Middle East contributed to a long standing conflict between the West and the Muslim World, eventually leading to the 9/11 attacks? I am examining the complex combination of political, religious and economic factors driven by the evolving US - Middle East relations, the root causes of terrorism, as well as the underlying motivations that drive terrorist activities. The key focus of my analysis is the September 11, 2001 terrorist attacks, and their immediate and long-term effects that have impacted the United States afterwards. Furthermore, I am examining how national security policies evolved and changed in response, the ways in which public view of terrorism shifted significantly and reshaped the United States society as a whole.