On a short walk through any modern city or university campus I might pass dozens or even hundreds of cameras. The cell phone in my pocket beams out my location constantly. License-plate readers scan my car’s tags without me even knowing it. Occasionally I volunteer my political views on Twitter. I probably post a selfie online just regularly enough to keep the facial-recognition software up to scratch.

For the most part, these sensors don’t currently talk to one another. When I walk past 50 cameras, they aren’t smart enough to piece together that the individual crossing each of their frames is the same person. They don’t know my Twitter handle, my political leanings, or the license number of the last car I drove. But when they start talking to each other — and if they can be sewn together with powerful aerial imagery — this “fused” surveillance will completely revolutionize policing, for better or for worse.

In a fully fused city, an aerial camera may autonomously detect my illegal U-turn and then track me to wherever I park. A license plate reader will check if I have outstanding violations in another state. Once I am on foot, the ground cameras pick up the slack. If I upload a photograph to Instagram from a street corner, my identity and the arrangement of pixels representing me in the imagery can be correlated, and my whole social media past will be laid bare to whoever considers me a subject of interest or suspicion.

In a fully fused city, an aerial camera may autonomously detect my illegal U-turn and then track me to wherever I park.

Such a system could have obvious appeals. In 2014, I happened to witness the shooting of a man named Taekwon Hart in Brooklyn, which remains unsolved. You can imagine how a fusion system might have helped investigators solve the case. A gunshot detector could have directed the CCTV cameras dotted around the neighborhood to begin tracking any suspects departing the scene of the crime. The cameras would, in turn, run the images of all passersby against a mugshot database to see if they have a criminal record. Once the suspects were identified, WAMI could have run the tapes backward in time, to see where they came from, and forward, to see where they escaped to. By the time the police arrive on the scene, the system could know exactly where the assailants are hiding, and who they are.

Now imagine the same technology was put to more nefarious uses.

Sure enough, the principles of automated sensor fusion are already catching on in the domestic sphere. About 80 local law enforcement agencies in 49 states, the District of Columbia, Puerto Rico, the US Virgin Islands, and Guam operate so-called fusion centers modeled on military war rooms that serve as a clearinghouse for information collected by a range of different agencies and private organizations. According to guidelines drafted by the Department of Homeland Security, these centers, which provide local agencies with access to “national threat information,” are geared toward fighting “violent extremism.”

Meanwhile, a number of U.S. law enforcement departments, including the Los Angeles Police Department, the Metropolitan Police Department in Washington, D.C., and the Virginia State Police have operated fusion software developed by the Silicon Valley firm Palantir that collates and analyzes criminal records, gang-member databases, number-plate rosters, social media archives, and even jailhouse telephone records to pinpoint individuals who are at risk of committing future violent crimes. (The company has worked extensively with the Pentagon and the intelligence community, and is rumored to have provided automated data-analysis services that assisted in tracking down Osama bin Laden.)

New York, Singapore, and a number of undisclosed cities operate an elaborate fusion system built by Microsoft called Aware that links both imagery and textual intelligence drawn from both municipal data repositories and live surveillance systems. A company representative I spoke with in 2017 said that the company was working on plans to bring Aware to various new markets. When I asked which markets, specifically, he declined to go into more detail either on or off the record, and abruptly ended the conversation.

In the months leading up to the 2022 World Cup, Qatar’s security agencies plan to use a fusion system called ARMED that will comb through social media posts, text messages, and intelligence reports on known terrorist networks, searching for people who might be likely to commit an attack. When a prototype of ARMED was run against a trove of data from the days leading up to the 2013 Boston Marathon, it placed the Tsarnaev brothers, perpetrators of the bombing that killed three people and wounded more than 260 others, in the top 100 individuals deemed most likely to commit an atrocity. If, during the World Cup, the software establishes that a particular suspect is indeed planning an imminent attack, it will fuse data from aerial drones, ground cameras, and cell phone trackers to lead police to the individual’s location before any damage can be done.

In China, a company called Dahua Technology sells a system that can recognize your face in a CCTV video and then automatically trace all of your movements across all other connected cameras up to a week back in time. It is even smart enough to figure out what car you own. The company has claimed that in cities with particularly dense CCTV coverage, its software will be able to identify those citizens, or dissidents, whom any individual target interacts with most frequently. Those people, in turn, can be tracked and matched with their associates. And so on, ad Orwellian infinitum. The potential for abuse of such systems is boundless.

It doesn’t help that we continue to willingly produce and upload volumes of fusible data from the most intimate corners of our lives. Just consider the internet of things (IoT), the networks of personal devices, vehicles, home appliances, and other previously inert electronic tools that are able to send and receive data.

It doesn’t help that we continue to willingly produce and upload volumes of fusible data from the most intimate corners of our lives.

Though these systems might add convenience to our lives, they will paint an incredibly detailed portrait of every one of us. By some estimates, there will be 80 billion smart devices in operation by 2025, with 150,000 new devices coming online every minute. The Pentagon already has designs to take advantage of all this free surveillance. “This immense, sparsely populated space of interconnected devices,” explains one Pentagon document, “could serve as a globe-spanning, multi-sensing surveillance system.” The document quotes legal expert Julia Powles, who wrote in 2015 that the IoT will be “the greatest mass surveillance infrastructure ever conceived.”