25 years after 9/11: Enduring legacies for America and the Middle East

As America marks the 25th anniversary of September 11, 2001, the shockwaves of that day still reverberate through its society, politics, national security, and global posture. The attacks set the United States on a path that would reshape the Middle East, redefine the boundaries of executive power, transform the economy, and recast the very idea of war and peace. Two and a half decades later, the legacy of 9/11 is neither settled nor static; it is an evolving set of challenges, dilemmas, and paradoxes that continue to shape the relationship between the United States and the wider world, nowhere more so than in the Middle East.

At the Brookings Institution’s Strobe Talbott Center for Security, Strategy, and Technology, a panel of distinguished experts convened to dissect how the threat of terrorism has evolved, how U.S. policy has responded and adapted (or failed to), and why a sober reckoning with the post-9/11 era is more urgent than ever. Drawing on the insights of this discussion, this analysis highlights the enduring impact of 9/11 on both the Middle East and the United States, while probing the new frontiers of the terrorism challenge—especially in an era of fragmented networks, technological acceleration, and shifting great power competition.

The shifting landscape of terrorism

Eric Schmitt, veteran national security correspondent at The New York Times, opened the conversation with a sobering observation: “There are actually more terrorists and more terrorist organizations now than there were on 9/11.” The threat has not receded; it has morphed, spreading across continents and changing form. The era of a single, unifying target (al-Qaida’s core leadership in Afghanistan) has given way to a complex mosaic of actors and motivations. Al-Qaida and ISIS remain “brands,” but their influence is often exercised through far-flung affiliates and franchises, from Yemen and Somalia to the Sahel and beyond.

Tricia Bacon, professor at American University in Washington, underscored South Asia’s continued centrality to global terrorism, calling it “the most important terrorist threat to the United States and to the West,” though its landscape has fundamentally changed. State sponsorship, once dominant, such as Pakistan backing anti-India groups and the Taliban, has become less clear-cut, with more unstable and blurred relationships between states and non-state actors. The Taliban, now ruling Afghanistan, acts independently, supporting both al-Qaida and groups targeting Pakistan. Meanwhile, ISIS-Khorasan (ISK) emerges as a significant, state-independent force, posing what Bacon calls “the most serious Sunni extremist threat in the world.” ISK’s transnational reach, including attacks beyond the region, highlights both its adaptability and the challenges of counterterrorism cooperation amid growing global mistrust.

Ambassador Jeffrey Feltman, Fellow at Brookings, drawing on decades of diplomatic service in the region, highlighted an unintended consequence of the U.S. response to 9/11: the empowerment of Iran and the proliferation of non-state proxy actors. The destruction of Saddam Hussein’s regime and the toppling of the Taliban removed key checks on Iranian influence. In the ensuing chaos, Iran expanded its network of partners—Hezbollah, Hamas, the Houthis, and various Shia militias in Iraq, creating a web of influence that now spans the region.

Feltman underscored the evolution of these proxies: where Hezbollah once acted as Iran’s primary regional instrument, its current existential struggle in Lebanon has shifted the balance, with the Houthis in Yemen increasingly serving as Iran’s forward-deployed lever over global trade chokepoints like the Bab el-Mandeb. This “web” of relationships, more horizontal than hierarchical, is both resilient and destabilizing, enabling Iran to disrupt adversaries and project power at a relatively low cost.

Fonteh Akum, director of the Africa Program at Carnegie Endowment for International Peace, identified Africa as today’s “epicenter” of terrorism, where weak states, porous borders, and incomplete state formation—not state sponsorship—enable local groups like Boko Haram and al-Shabaab to thrive and affiliate with global networks. New technologies such as drones and cryptocurrencies further complicate counterterrorism efforts. By controlling cross-border regions and exploiting governance gaps, these groups not only destabilize Africa but also provide safe havens for terrorist organizations to regroup and reemerge elsewhere.

The evolving U.S. response

A central theme in the Brookings discussion was the shift in U.S. national security strategy. The urgency of counterterrorism, which united even adversarial states in the years after 9/11, has faded. The U.S. now prioritizes strategic competition with China and Russia, relegating counterterrorism to a secondary concern. While this reorientation may be justified by emergent threats, it has weakened the international partnerships and multilateral mechanisms that sustained two decades of counterterrorism cooperation.

As Bacon observed, “the counterterrorism compacts are really becoming much more frayed.” In places like Somalia, middle powers such as Turkey now play outsized roles, filling the void left by U.S. retrenchment. Meanwhile, the United Nations—once effective at coordinating global counterterrorism through Security Council mandates—finds itself paralyzed by great-power deadlock.

Vanda Felbab-Brown, Senior Fellow at Brookings, highlighted the troubling trend of applying counterterrorism frameworks to organized crime, particularly in Latin America. The designation of criminal cartels as terrorist organizations, an approach embraced by both the Trump administration and right-wing governments in the region, has justified the use of military force in place of law enforcement and eroded civil liberties. “The counter-terrorism prism is throwing out or at least significantly eviscerating civil rights, civil liberties, and it’s being used by governments as a path toward authoritarianism,” Felbab-Brown warned.

This phenomenon is not confined to Latin America. In the United States, the expansion of executive power and emergency authorities, justified in the name of security, has left a legacy that is increasingly turned inward, fueling fears of domestic repression and the misuse of security institutions for political ends.

The post-9/11 era saw the creation of vast new security bureaucracies (the Department of Homeland Security, the Office of the Director of National Intelligence), the expansion of the surveillance state, and the normalization of emergency powers. Bill Galston, Senior Fellow at Brookings, traced the unprecedented growth of executive authority, enabled by Congressional acquiescence and public support in the wake of 9/11. “We now have more than 130 separate congressional grants of emergency power to the president with no time limits, no sunset clauses, no nothing,” he noted.

Economically, the war on terror contributed to the ballooning of U.S. public debt and the rise of “economic statecraft” as a national security tool. Ben Harris, Brookings Vice President and Director of Economic Studies, detailed how the Treasury Department’s role shifted from traditional fiscal management to wielding sanctions and financial regulations as instruments of foreign policy. Sanctions, once targeted at states, now extend to non-state actors and entire sectors, reshaping the global financial system.

The Middle East: Lasting change, enduring instability

Suzanne Maloney, Brookings Vice President and Director Foreign Policy program, offered a nuanced perspective on the evolution of U.S.-Iran relations. In the immediate aftermath of 9/11, there was a fleeting moment of sympathy and even tacit cooperation between Tehran and Washington. Iranian officials facilitated U.S. operations in Afghanistan, and for a brief period, strategic interests aligned against the Taliban. That moment, however, was squandered. The Bush administration’s decision to sever diplomatic engagement after attacks attributed to al-Qaida elements based in Iran and the subsequent invasion of Iraq deepened the U.S.-Iranian estrangement and set the stage for decades of confrontation.

Ironically, U.S. actions in Iraq and Afghanistan removed Iran’s immediate adversaries, enabling Tehran to expand its influence through proxies and to develop asymmetric capabilities that now shape the regional balance of power. The resulting landscape is one of hedging and diversification, as Gulf states seek alternatives to the American security umbrella while building new relationships with China, Turkey, and even Iran itself.

A recurring concern throughout the panels was the rapid diffusion of technology, cryptocurrency, AI, and drones into the hands of terrorist and criminal groups. These tools lower barriers to entry, enable autonomous operations, and allow attacks at a distance with minimal resources. As Felbab-Brown observed, “the criminal groups and terrorist groups are using AI, not just for tactics, but increasingly to rethink strategy… they will have the capacity to conduct very lethal attacks very far away with very few people.”

The implications for U.S. and allied counterterrorism are profound: regulatory frameworks lag behind innovation, and the ability to attribute and disrupt attacks is diminished.

The panelists agreed that international partnerships, once the backbone of the post-9/11 counterterrorism effort, are fraying. The U.S. shift toward unilateralism and the retreat from multilateral leadership have created vacuums that regional actors with parochial interests are filling. As Bacon highlighted, “there is a fraying of a lot of that investment in counterterrorism partnerships and relationships that we relied on for the 20 years or so after 9/11.” Whether in Afghanistan, where the Taliban have outlasted international coalitions, or Africa, where regional security arrangements struggle to keep pace with transnational threats, the erosion of coordination is palpable.

The Brookings discussions emphasized that, while the U.S. response to 9/11 achieved impressive coordination and power, it also produced unintended consequences, bolstering adversaries, weakening democratic norms, and creating new insecurities. As U.S. foreign policy pivots toward great power competition, counterterrorism tools and approaches could be misapplied elsewhere, at home and abroad. The future threat landscape will be shaped by persistent grievances, technological advances, and resilient transnational networks.

The panelists agreed: America's challenge is not just defeating terrorism, but doing so while upholding the values, alliances, and institutions that underpin its legitimacy. Twenty-five years after 9/11, this work remains unfinished. The enduring lesson is that security cannot come from force or surveillance alone, but from strong institutions and the willingness to adapt and reflect. Striking a balance between vigilance and restraint, security and liberty, and power and partnership will be as crucial in the next quarter-century as it was in the last.