Twenty-five years ago, the terrorist attacks of 11 September 2001 killed 2,977 people and changed the course of international security. As we remember those who lost their lives, the anniversary also calls for reflection on the decisions that followed and the world those decisions helped to shape.
The US-led “war on terror” brought military intervention in Afghanistan and, subsequently, Iraq, alongside prolonged counterterrorism operations across the Middle East and beyond. Although the two wars had different origins and justifications, both became central to an era in which counterterrorism dominated Western security policy.
A quarter of a century later, the consequences remain relevant to defence, diplomacy and strategic leadership.
The post-9/11 era raises a fundamental question: how can military strength deliver lasting political outcomes?
For defence and security leaders, the lesson is to connect operational objectives with a credible long-term strategy. Winning battles, removing a regime and building a sustainable peace are distinct challenges. Each requires clarity of purpose, an understanding of local conditions and an honest assessment of what external intervention can achieve.
There are equally important questions about legitimacy. How did American foreign policy reshape perceptions of the United States and its allies? And what happens to strategic influence when an intervention’s stated intentions diverge from people’s experience on the ground?
Understanding the consequences for the Middle East requires more than a Western perspective. Regional politics, governance and the experiences of communities affected by conflict must sit at the centre of any assessment.
The region’s conflicts cannot be explained by 9/11 alone. Examining the period means recognising both the effects of external intervention and the decisions of regional actors.
The anniversary also prompts a question about strategic attention: how did two decades focused on counterterrorism affect Western preparedness for renewed competition with Russia and the rise of China?
For the defence and security community, this is an enduring challenge. Responding to an immediate threat must be accompanied by the capacity to anticipate other risks, question assumptions and adapt.
Chatham House’s podcast, How did 9/11 shape the world?, explores these themes. Hosted by Laurel Rapp, the discussion brings together General Sir Richard Barrons, Farea Al-Muslimi and Jason Burke.
For UDSS, this anniversary offers an opportunity to encourage informed reflection on the relationship between military power, political purpose and long-term security.
Listen to the Chatham House discussion.