ESSAY: How 9/11 Changed Government Surveillance of Citizens, Part One

This essay by Amanda Watford appeared on Colorado Newsline on September 11, 2026. We are sharing it in two parts.

Twenty-five years after 9/11, the surveillance infrastructure built and expanded in its aftermath has become part of a far larger digital ecosystem — producing tools that can collect and analyze information on a scale unimaginable in 2001.

The attacks of September 11, 2001, did more than reshape the nation’s approach to terrorism. They changed the architecture of American intelligence and policing. They expanded how government agencies collect, share and analyze information, and brought national security tools deeper into ordinary law enforcement.

The infrastructure built in the attacks’ aftermath has proved remarkably durable. Joint terrorism task forces and fusion centers brought federal, state and local agencies into closer intelligence-sharing networks. New laws expanded the government’s ability to obtain information. And police departments acquired technologies that once belonged largely to the realm of national security.

But the expansion of surveillance did not go uncontested. Civil liberties groups warned that the new powers could erode Americans’ privacy and constitutional protections, while many Americans accepted expanded government surveillance as a necessary tradeoff for safety in the aftermath of the attacks.

The country also entered a period of heightened scrutiny for people perceived as foreign or potentially threatening — with American Muslims and immigrant communities bearing a particularly heavy burden.

Then came the digital revolution.

Americans began carrying smartphones, broadcasting their lives on social media and generating enormous amounts of commercially collected data. Police gained access to license plate readers, networks of cameras, cellphone location information and other technologies capable of tracking people and mapping their movements.

Now, artificial intelligence is adding another layer: systems that can sift through those vast stores of information, connect previously separate databases and generate analyses in seconds.

Some surveillance and privacy experts say that the amount of information available to the government — and its ability to make sense of it — has fundamentally changed since 9/11.

That has taken on new urgency as surveillance systems have moved further into everyday life. Automated license plate readers can track where people drive. Facial recognition can help identify people in crowds. Commercial data can reveal where and how people live and travel. And increasingly, artificial intelligence can analyze and connect these streams of information at a speed no human investigator could match.

Those capabilities have raised concerns among some experts and advocates about how surveillance could be used to monitor protests, track immigrants and identify people seeking reproductive healthcare.

Gregory Nojeim, senior counsel and director of the security and surveillance project at the Center for Democracy & Technology, described the post-9/11 era as a “perfect storm.”

“That storm is both the expansion of the legal powers that have been conferred on the government to collect and share information, combined with the advance of technology, which has given the government more tools to collect information from more people in more contexts,” Nojeim said.

From intelligence silos to everyday policing
In the months after 9/11, officials sought to fix a critical weakness exposed by the attacks: Intelligence that could have helped uncover the plot was held across government agencies that failed to connect or share it effectively. The response was a sweeping effort to tear down those silos and build a more integrated intelligence network.

Federal, state and local agencies quickly expanded intelligence-sharing, and the government established and expanded networks designed to move information across traditional institutional boundaries. The FBI’s Joint Terrorism Task Forces brought together federal, state and local law enforcement and intelligence personnel.

Fusion centers, generally run by state and local governments with federal support, became another part of the post-9/11 intelligence architecture, with at least one operating in every state. The centers serve as intelligence hubs where law enforcement agencies can share information, analyze data and flag potential threats across jurisdictions.

Katie Kinsey, chief of staff and tech policy counsel at the Policing Project at the NYU School of Law, said the original goal was straightforward — prevent another terrorist attack.

Over time, some fusion centers began supporting investigations and enforcement involving lower-level crimes, Kinsey said. Local police departments also developed their own versions of centralized intelligence hubs, often called real-time crime centers, that can integrate information from cameras, automated license plate readers and other surveillance systems.

David Viola, an adjunct professor at the Center on Terrorism at John Jay College of Criminal Justice and author of “You Have Unleashed a Storm: New York City’s Descent into Chaos During America’s Most Explosive Era of Radical Violence,” said the post-9/11 period also marked a major shift in the kind of information available to investigators.

Before the attacks, he said, intelligence work relied heavily on traditional investigative techniques. Today, digital records can provide information about where people go, with whom they communicate, what they purchase and what they post online.

But technology is only part of the transformation. Viola said the institutional relationships forged among local, state and federal authorities after 9/11 are among the period’s most lasting legacies.

“These are institutions that have cemented the close coordination between state, local, federal, tribal authorities in the past 25 years, and they’re going nowhere, for better or worse,” he said.

Nojeim, of the Center for Democracy & Technology, was directing lobbyists in Washington, D.C., on 9/11. His office was evacuated as officials tried to determine whether the U.S. Capitol was the target of another hijacked plane.

In the aftermath, he said, civil liberties advocates understood that decisions made in response to the attacks could extend far beyond the immediate crisis.

About a month after the attacks, the USA PATRIOT Act was signed into law, dramatically expanding the federal government’s ability to collect information and conduct surveillance in terrorism investigations. Some of its most sweeping surveillance authorities were later curtailed or allowed to expire, but the law helped establish a new framework for national security surveillance that continues to shape how Americans’ data is collected and monitored.

“In the days after 9/11, we all realized that what the government did in the next few days to respond could have lasting implications for the civil liberties of Americans,” Nojeim said…

Read Part Two… tomorrow…