Which landmark event occurred on September 11, 2001, during George W. Bush's presidency?

The event that occurred on September 11, 2001, was a series of coordinated terrorist attacks carried out by the extremist group al-Qaeda against the United States. This tragic day marked a significant shift in American foreign and domestic policy, leading to the initiation of the War on Terror, which involved military action in Afghanistan and broader efforts to combat terrorism globally.

The War on Terror was characterized by a range of actions, including military invasions, the establishment of the Department of Homeland Security, and new counter-terrorism legislation. This response to the attacks fundamentally changed U.S. military and foreign strategies and established a new national security framework that prioritized countering terrorism as a key objective.

In contrast to this, while the bombing of the Murrah Federal Building was a significant domestic terrorist act that occurred in 1995, it is not associated with the events of September 11, 2001. Similarly, the signing of NAFTA took place in 1993 and focuses on trade agreements between the U.S., Canada, and Mexico, while the ratification of the Defense of Marriage Act occurred in 1996 and pertains to the legal definition of marriage, neither of which are related to the significant changes prompted by the events of 9/11.