Beyond the War on Terror: What 9/11 Can Teach U.S. Foreign Policy 25 Years Later

Twenty-five years ago, the September 11 attacks fundamentally altered the way the United States viewed its security and its role in the world. Terrorism went from one of many national security concerns to a defining priority of American foreign policy, leading the U.S. into Afghanistan, expanding counterterrorism operations, and strengthening intelligence. 

The attacks revealed a failure of imagination: U.S. institutions had failed to adequately anticipate how a non-state actor operating thousands of miles away could affect the lives of many American citizens. 

The United States of 2026 faces a very different international security landscape than it did 25 years ago. Terrorist organizations have not disappeared, but rather exist alongside cyber operations, artificial intelligence, unmanned aircraft systems, and war. 

But, some of the most consequential changes have occurred beyond U.S. measures. Just one day after 9/11, NATO moved to invoke Article 5 of the North Atlantic Treaty for the first time in history, declaring that an attack on one ally meant an attack on all. Today, intelligence sharing and cooperation with foreign governments have become increasingly vital for identifying terrorist networks. 

The attacks demonstrated that geographical distance no longer insulates the United States from instability abroad. In 2001, we learned those lessons through al-Qaeda’s ability to successfully plan attacks from Afghanistan. Today, the same principle applies to threats such as drones. 

The Iranian-backed Houthis in Yemen, for example, have used unmanned aerial systems to target U.S. naval forces and commercial shipping in the Red Sea. These attacks demonstrate how relatively accessible technology can allow an armed group to threaten international trade routes, U.S. forces, and regional stability. 

Since the 9/11 attacks, technology has changed, but the underlying lesson still lingers: the U.S. needs to be ready to fight threats developing far beyond our borders in order to ensure safety for every American citizen.