9/11, 23 Years Later: Legacies and Lessons in an Ever-Changing World

September 11Photo byrds323 / Wikimedia Commons

It’s been 23 years since September 11, 2001, a day seared into the consciousness of not just Americans, but the world. The tragic events of that Tuesday morning—terrorist attacks that obliterated the World Trade Center, damaged the Pentagon, and crashed a plane into a quiet field in Pennsylvania—reshaped the United States in ways that continue to ripple outward. On this somber anniversary, Americans gather at memorials in New York City, Washington, D.C., and Shanksville, Pennsylvania, to honor the nearly 3,000 lives lost. But with each passing year, the legacies of that day become more layered, pushing us to reflect not only on what was lost but also on the lessons still being learned—and the stakes that remain.

The world we live in today, 2024, feels far removed from the world of 2001, yet its shadow is undeniable. The wars in Afghanistan and Iraq may be over, but the scars—on both sides—remain fresh. Surveillance, once the stuff of dystopian fiction, has become routine. Our polarized political landscape, shaped by the post-9/11 era, seems to grow more fractured by the day. And even as we confront a slew of new challenges—cyberattacks, pandemics, the rise of authoritarianism—the lessons of that fateful day continue to echo in American foreign and domestic policy, sometimes complicating more than clarifying.

A Memory That Endures

At Ground Zero in Lower Manhattan, where the Twin Towers once touched the sky, the National September 11 Memorial & Museum preserves the memory of that catastrophic morning. Every year, the names of the dead are read aloud, ensuring that the personal, human toll of the attacks is never forgotten. Families, survivors, first responders—they return annually, united by loss but buoyed by resilience.

The crowd includes those who weren’t even born when the attacks happened. For younger generations, 9/11 isn’t a memory but an indelible part of the national fabric, embedded in history books, woven into popular culture, and omnipresent in conversations about terrorism, security, and America’s place in the world.

“The loss is still raw for many of us,” says Mary Fetchet, whose son died in the attacks. “But over the years, I’ve seen how younger people have become more aware of what that day meant—not just the tragedy, but everything that followed. It’s complex, but we have to keep remembering, keep talking about it.”

The Long Shadow of War

One of 9/11’s most lasting impacts was the launch of the War on Terror, a campaign that spanned two decades and stretched across the globe. In response to the attacks, the U.S. invaded Afghanistan, aiming to dismantle the Taliban and root out Osama bin Laden’s al-Qaeda network. Two years later, the U.S. turned its attention to Iraq, launching a controversial war based on now-disproven claims of weapons of mass destruction.

The wars are over—American troops withdrew from Afghanistan in 2021—but the legacy of those conflicts still looms. Afghanistan is once again under Taliban control, and the grand ambitions of democratizing the region seem like distant dreams. For many, the sacrifices—trillions of dollars spent, thousands of lives lost—feel like they were in vain.

“Looking back, we can see that our strategies were deeply flawed,” says Andrew Bacevich, a retired Army colonel and historian. “We waged wars that, in the end, didn’t produce the results we envisioned. Twenty-three years after 9/11, we’re still grappling with the aftermath—both abroad and here at home.”

The Rise of a Surveillance State

The attacks didn’t just reshape U.S. foreign policy; they also ushered in a new era of domestic surveillance and security. Within weeks of 9/11, Congress passed the Patriot Act, dramatically expanding the government’s ability to monitor citizens and intercept communications in the name of national security.

Although some of those measures have since been scaled back, the surveillance apparatus remains firmly in place. From TSA checkpoints at airports to the mass data collection programs exposed by whistleblower Edward Snowden, the post-9/11 world has transformed how we think about privacy and civil liberties.

“The attacks of 9/11 gave the government a carte blanche to build an infrastructure of surveillance that we still live under,” says Jameel Jaffer, executive director of the Knight First Amendment Institute. “While some reforms have been made, it’s staggering how much we’ve accepted these intrusions into our lives as normal. The legacy of this surveillance state might be one of the hardest things to dismantle.”

A Fractured Political Landscape

In the immediate aftermath of 9/11, there was a sense of national unity—albeit brief. But over time, the wars in Iraq and Afghanistan, once widely supported, became contentious. The policies and security measures that followed sowed deep divisions, with some Americans viewing them as necessary defenses against future attacks, while others saw them as overreach.

The years since have seen these divisions widen into gaping chasms. The post-9/11 climate of fear and insecurity helped fuel a political culture rife with conspiracy theories, xenophobia, and distrust in government institutions. Domestic extremism, once a fringe concern, has come to the forefront as an increasingly urgent threat.

“9/11 brought us together for a moment,” says Julian Zelizer, a political historian. “But it also laid the groundwork for the intense polarization we see today. The global war on terror became a deeply polarizing issue, and it continues to influence our politics, our society, in ways we couldn’t have predicted.”

Lessons for an Uncertain Future

As the nation marks the 23rd anniversary of 9/11, the lessons from that day and its aftermath remain critical—perhaps more than ever. The threats America faces have shifted, from traditional terrorism to cyberattacks, great power competition, and global health crises. Yet, the lessons of 9/11 endure.

Chief among those lessons is the importance of global cooperation. The fight against terrorism underscored the necessity of international alliances, a truth that feels just as vital in today’s world of shared challenges, from climate change to pandemics. “We learned the hard way that going it alone doesn’t work,” says Susan Rice, former National Security Advisor. “Whether it’s counterterrorism, climate policy, or public health, the U.S. must engage with the world, not retreat from it.”

At home, the balance between security and civil liberties continues to be a pressing issue. With new forms of violence emerging—domestic and foreign—debates over the extent of government surveillance, privacy, and freedom remain central to the American discourse.

A Nation Forever Marked

Even more than two decades later, 9/11 remains a pivotal moment in American history. Its legacy is one of profound change—wars that redefined U.S. foreign policy, the rise of the surveillance state, and a political landscape that grows more fractured with each passing year.

As the country gathers to remember those who perished on that terrible day, Americans also confront the uncertainty of what lies ahead. The lessons from 9/11 are still being absorbed, still shaping the future.