Nathan Freed Wessler

They had obtained the records with court orders under the Stored Communications Act, which require “specific and articulable facts showing that there are reasonable grounds to believe” that the records are relevant and material to an ongoing criminal investigation. No warrant was sought.

In a March 2015 friend-of-the-court brief to the Sixth Circuit, Wessler and his colleagues set the records beside the defendant’s account of attending a Detroit church, which Wessler had obtained in a telephone conversation with him. In the early afternoon on a number of Sundays, his calls ran through the tower sectors that cover the church; those sectors did not routinely appear in his records on other days of the week, from which, the brief said, one could infer that he was worshipping at those times. The same records placed the calls that closed each night and opened each morning near his home from December 23 to 27, 2010, suggesting where he slept.

Wessler argued the case at the Supreme Court on November 29, 2017. On June 22, 2018, Chief Justice John Roberts’s majority opinion held that acquiring the historical cell-site records was a Fourth Amendment search, and that the government “must generally obtain a warrant supported by probable cause before acquiring such records.” The Court declined to extend the third-party doctrine to a chronicle of location information it called “detailed, encyclopedic, and effortlessly compiled.” With such records, it wrote, “police need not even know in advance whether they want to follow a particular individual,” and the carriers then kept them for up to five years.

Finding the Surveillance in the File

Wessler graduated from Swarthmore College and worked as a field organizer in the ACLU’s Washington Legislative Office before law school. After New York University School of Law, he clerked for Judge Helene N. White of the Sixth Circuit and returned to the ACLU in its National Security Project. He later joined the Speech, Privacy, and Technology Project as a staff attorney and is now its deputy director.

His early work examined the cell-site simulator, often called a "stingray," a device that masquerades as a cell tower, tricking the phones within its range into connecting so that police can pinpoint their location, including the phones of people never suspected of a crime.

In February 2015 he published the records the ACLU had obtained from Florida agencies. The Tallahassee Police Department listed more than 250 investigations from September 2007 through February 2014; a sample of its applications and court orders never mentioned the technology. One of its investigative files said that an investigator “arrived and determined that [the tracked] telephone was on the second floor of the apartment,” without saying how. A court transcript the ACLU had helped unseal identified that investigator as the officer who operated the department’s Stingrays. The state’s law-enforcement department had signed a nondisclosure agreement with Harris Corporation, the device’s maker, and the FBI had required local agencies to sign such agreements before buying the devices. Wessler argued from the records that police must obtain warrants and that the secrecy must end. In September 2015 the Justice Department announced that its agents must obtain a search warrant supported by probable cause before using a cell-site simulator, with exceptions for exigent or exceptional circumstances.

A City’s Retained Images

Wessler and his colleagues relied on Carpenter in Leaders of a Beautiful Struggle v. Baltimore Police Department, brought for Leaders of a Beautiful Struggle, a think tank that advances the public-policy interests of Black people in Baltimore, Erricka Bridgeford, a co-founder of Baltimore Ceasefire 365, and Kevin James, a community organizer. The police department’s Aerial Investigation Research pilot flew camera-equipped planes over the city at least forty hours a week. Each image covered about thirty-two square miles in daylight, with people appearing as “blurred dots or blobs,” and the imagery could be combined with ground cameras and license-plate scanners to trace a person’s movements after the fact.

On June 24, 2021, the en banc Fourth Circuit, by a vote of 8 to 7, held that “accessing its data is a search, and its warrantless operation violates the Fourth Amendment,” and reversed the denial of a preliminary injunction. Under the settlement that followed, the city may not implement a similar program, the police may reach the collected data only for existing prosecutions or criminal-defense discovery, and the records are to be deleted once every prosecution that relied on them is final.

Faces and Devices

The ACLU’s suit against Clearview AI, filed in May 2020 under Illinois’s Biometric Information Privacy Act, challenged a database of more than three billion faceprints captured from images available online, which Clearview had offered to private companies and to law enforcement agencies. The May 2022 settlement permanently barred Clearview from giving most private entities nationwide access to the database and barred it for five years from giving access to any state or local government entity in Illinois, including the police. Wessler said the company “can no longer treat people’s unique biometric identifiers as an unrestricted source of profit.”

Under the settlement, Illinois residents can upload a photograph and complete a form to block their faceprints from Clearview’s search results, including searches by police. Clearview agreed to spend $50,000 on internet advertising for the opt-out, and the uploaded photographs may be used only to run it.

In Alasaad, Wessler and his colleagues at the ACLU, the ACLU of Massachusetts and the Electronic Frontier Foundation represented eleven travelers whose phones and laptops had been searched at the border. Customs and Border Protection had conducted more than 33,000 device searches the year before, he said: “That is not rare. But even if it were, it’s still unconstitutional.” In November 2019, Judge Denise Casper of the federal district court in Boston ruled that agents must have reasonable suspicion that a device contains digital contraband before searching it.

Tracing the Basis for an Identification

In December 2020 the ACLU sued the Department of Homeland Security, ICE and CBP under the Freedom of Information Act for records of the agencies’ purchases of cell-phone location data. If law enforcement agencies can “buy their way around the Fourth Amendment’s warrant requirement,” Wessler wrote, the protection the Supreme Court recognized in Carpenter is at risk.

In April 2026, Wessler and his colleague Lauren Yu described the case of Kimberlee Williams, an Oklahoma resident who spent six months in jail over bank fraud in Maryland, a state she had never visited. A bank investigator had sent a surveillance image to Crimedex, a national email list of police and private investigators. Someone on the list ran the image through facial-recognition software and sent back her name and photograph as a match. A Montgomery County detective was told she had been identified “using facial recognition software”; by the time the identification reached the other two counties, she had only been “recognized.” Detectives never tried to establish whether an Oklahoma resident could have been in Maryland; geotagged posts from Oklahoma would have shown that she was not the person in the image.

On April 14, 2026, the ACLU and the ACLU of Maryland filed administrative complaints against the police departments of Montgomery, Prince George’s and Anne Arundel counties. They asked the departments to investigate, to apologize publicly, and to bar reliance on facial-recognition searches run by outside entities and arrests based only on a facial-recognition result followed by a human identification.

Surveillance Inside the Home

On September 2, 2026, Wessler and lawyers from the ACLU, the ACLU of New Hampshire and New Hampshire Legal Assistance filed a class action in Merrimack County Superior Court for tenants of the Concord Housing and Redevelopment Authority. Beginning in the fall of 2024, the authority had installed Minut Monitor devices in roughly 300 apartments. The devices log noise levels, motion, smoke and humidity and scan for nearby Bluetooth devices to estimate how many people are present, and the authority’s employees can see the data remotely, in real time. The tenants allege that the authority has collected hundreds of millions of data points and keeps them indefinitely.

They seek a ruling that the collection, made without their consent, violates the New Hampshire Constitution, an order stopping the surveillance and the deletion of the data. “It’s an incredible imposition on people’s privacy in their homes,” he said. Logged minute by minute, the readings can show, the tenants say, when residents wake, when they come and go, and when they have visitors.