In the past 24 hours, I’ve checked Google Maps for directions, logged a sunset run on Strava, booked a yoga class with ClassPass, swiped into the New York City subway using a card linked to a digital profile, and sent and received hundreds of emails, texts, Slack messages, and phone calls. Meanwhile, my iPhone passively logged each of my 13,444 steps, while my face and gait were recorded by countless discreet cameras—both those installed by the city and by my neighbors. Then, of course, there are the Google searches, the Instagram likes, the re-posts on X and Bluesky.

If somebody—a police officer, a prosecutor, an FBI agent—were to get ahold of all this data, they’d be able to sketch out a pretty complete picture of my daily life. In most cases, I probably wouldn’t even know that my data had been obtained.

“We should have a conversation, both individually and collectively, about what the stakes are when we build these networks of digital surveillance all around us without thinking about the consequences.”

For decades, civil libertarians and privacy experts have warned about the surveillance threat posed by digital technologies. But if those risks ever felt abstract, they’ve become all too real during Donald Trump’s second term: To aid its mass deportation agenda—and, at times, intimidate those who protest against it—Immigration and Customs Enforcement (ICE) has gone on a $300 million spending spree, buying up surveillance technology powered by a mix of federal, state, and commercial data systems.

In his new book Your Data Will Be Used Against You: Policing in the Age of Self-Surveillance, George Washington University law professor Andrew Guthrie Ferguson details how the rise of digital technology and smart devices has led to massive amounts of data being created, aggregated, and shared with law enforcement—and how our own consumer choices have ensnarled us in this web of digital surveillance. Ferguson surveys various court cases to show how our legal system offers few protections if a police officer—or a tyrannical government—wants to weaponize your data against you. I spoke with him the current legal landscape, how the second Trump administration has turbocharged state surveillance, and what lawmakers and citizens can do to protect their digital privacy.

This interview has been edited for length and clarity.

What inspired you to write this book?

I wrote a book called The Rise of Big Data Policing, which was about how police departments were buying technology directed at their citizens and what that meant. And this book was more of an internal sense of, “What are we doing? What’s our complicity in building these networks of self-surveillance?” Because I think we all think that we are buying this for our own consumer benefit—I’m protecting my home by buying this Ring doorbell camera—and not necessarily thinking, oh, wait a minute, that means there’s now footage of every time any family member has left the house and what they’re doing. And that data is available, at least with a warrant, if police want to get access to it. We should have a conversation, both individually and collectively, about what the stakes are when we build these networks of digital surveillance all around us without thinking about the consequences.

When talking about surveillance, there’s often this mindset of, “If I’m not doing anything wrong, why should I worry?” But your book shows how consumer data can be used to power racially biased predictive policing algorithms or criminalize things like obtaining an abortion, seeking gender-affirming care, or engaging in First Amendment-protected activity. What do you say to someone who isn’t concerned about buying into self-surveillance?

First, we’ve seen in the last few months that the federal government seems willing to weaponize the criminal justice system for politicized prosecutions. That changes who is at risk for criminality and who can say, “But I’m not doing anything wrong.” Eight million Americans went out and protested in No Kings. It’s pretty easy to call some of them supporting some level of sedition or treason or “part of antifa,” and we’ve already seen that kind of dissent criminalized in certain ways. If your Ring doorbell camera caught you walking out with a No Kings sign, or your cellphone revealed that you were at a protest, or you sent some........

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