The chief concern of the War on Terror after 9/11 was the prevention of further terrorist attacks against the United States and its allies. Initiated in response to the September 11 attacks in 2001, which were carried out by al-Qaeda, the U.S. aimed to dismantle terrorist networks and prevent the spread of extremist ideologies. This led to military engagements in Afghanistan to oust the Taliban regime, which had provided a safe haven for al-Qaeda. U.S. policies also included increased intelligence sharing, counterterrorism operations, and enhanced homeland security measures. The War on Terror has had profound implications for international relations, security policies, and civil liberties.