Nathan Freed Wessler

Before Nathan Freed Wessler argued Carpenter v. United States at the Supreme Court, he examined what Timothy Carpenter's phone records could disclose about activities unrelated to the criminal investigation. Prosecutors had obtained 12,898 location points from wireless carriers, an average of 101 a day across 127 days. They used court orders under the Stored Communications Act, which required specific and articulable facts showing reasonable grounds to believe the records were relevant and material to an investigation, rather than warrants based on probable cause.

In a 2015 friend-of-the-court brief to the Sixth Circuit, Wessler and his colleagues compared the records with Carpenter's account of attending church, which Wessler had obtained in a telephone conversation. On several Sunday afternoons, Carpenter's phone connected to towers near the church; those connections did not routinely appear on other days. The brief argued that even without precise coordinates, a pattern of tower connections could reveal religious activity. The same records could suggest where a person slept or whom he visited, exposing private routines beyond the locations under investigation.

Wessler presented the argument to the Supreme Court on November 29, 2017. In June 2018, Chief Justice John Roberts's majority opinion held that acquiring the historical cell-site location record was a Fourth Amendment search generally requiring a warrant. The Court declined to extend the third-party doctrine, which ordinarily denies constitutional protection to information voluntarily shared with a business, to the pervasive, largely involuntary location records generated through phone use. It also emphasized the ability to reconstruct movements after the fact: carriers then retained records for up to five years, whether or not anyone had been suspected of a crime when those records were created.

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. He attended New York University School of Law as a Root-Tilden-Kern public-interest scholar, clerked for Judge Helene N. White of the Sixth Circuit and returned to the ACLU as a National Security Project fellow. He later joined the Speech, Privacy, and Technology Project, where he is now a deputy director.

His early work examined the cell-site simulator, often called a "stingray," a device that imitates a cell tower to identify and locate nearby phones, including those of bystanders. These suitcase-sized devices could be deployed without a clear description in the records given to a judge or defense lawyer. Wessler helped lead litigation and public-records investigations into their use across the country, confronting nondisclosure agreements with the FBI and the equipment manufacturer.

In a 2015 report on records obtained from Florida agencies, he compared Tallahassee investigative files with a transcript the ACLU had persuaded a court to unseal. One file said an investigator had determined that a phone was on an apartment building's second floor, without explaining how. The transcript identified that investigator as the department's Stingray operator. The applications supplied by Tallahassee likewise omitted a description of the technology. Wessler used the documents to argue for disclosure and warrants; later that year, the Justice Department adopted a general probable-cause warrant requirement for its own use of cell-site simulators, with limited exceptions.

A City's Retained Images

Wessler and his colleagues invoked Carpenter in Leaders of a Beautiful Struggle v. Baltimore Police Department, representing Black community advocates challenging an aerial-surveillance program. Aircraft photographed about thirty-two square miles at a time during daylight hours, leaving analysts a record from which to trace movements through the city. People appeared as blurred dots, but the photographs could be combined with ground cameras and license-plate records to identify them and reconstruct routes.

In June 2021, the en banc Fourth Circuit held that access to the program's accumulated data was a search and its warrantless operation violated the Fourth Amendment. The ruling established the plaintiffs' entitlement to preliminary relief. The subsequent settlement barred resumption of the program and restricted access to the collected records, while preserving their availability for existing prosecutions and criminal-defense discovery. Deletion was tied to completion of the relevant prosecutions and direct appeals.

Faces and Devices

As plaintiffs' counsel in the ACLU's case against Clearview AI, Wessler helped negotiate restrictions on a face-search database built from billions of photographs scraped from the internet and offered to businesses and government agencies. The suit used Illinois's Biometric Information Privacy Act to challenge collection without consent. Its 2022 settlement established a permanent nationwide restriction on access for most private entities and a five-year ban covering Illinois state and local agencies and their contractors. The Illinois restriction did not extend to federal agencies.

The agreement also required an opt-out process through which Illinois residents could submit a photograph to block search results identifying them. Clearview had to use its best efforts to prevent further collection of their photographs and restrict use of the submitted images to administering the opt-out protection and meeting specified litigation obligations.

In Alasaad, Wessler and his ACLU and Electronic Frontier Foundation colleagues challenged searches of travelers' phones and laptops at the border. They obtained a 2019 district-court ruling requiring reasonable suspicion that a device contained digital contraband, although the First Circuit narrowed those protections in 2021. His 2022 public explanation of border searches stressed that wanting to keep personal information private did not imply that a traveler had committed a felony.

Tracing the Basis for an Identification

Wessler's project continues to litigate, testify and publish about surveillance, including automatic license-plate readers that accumulate travel records and the government's purchase of data from commercial brokers. In a 2020 public-records suit, the ACLU sought contracts, policies and legal analyses explaining federal agencies' purchase of phone-location data. Wessler argued that the government should not be able to avoid Carpenter's protections by paying for access instead of requesting the records from a carrier.

In April 2026, he and colleague Lauren Yu described their work for Kimberlee Williams, an Oklahoma resident wrongly identified as a suspect in Maryland bank fraud. A bank investigator had circulated a security-camera image through an investigators' mailing list. An unidentified recipient ran a facial-recognition search and returned Williams's name. As the identification passed to police in different counties, the explanation that it came from a facial-recognition search was reduced or omitted.

The ACLU and its Maryland affiliate filed administrative complaints on Williams's behalf seeking an apology and changes to investigative practices. Their proposals included barring reliance on facial-recognition searches performed by outside entities and prohibiting arrests based only on a computer match followed by a person's visual comparison. Wessler and Yu pointed to social-media posts geotagged to Oklahoma that the investigators had failed to check.

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 on behalf of public-housing residents challenging surveillance devices installed inside apartments owned by the Concord Housing and Redevelopment Authority. The Minut Monitor devices recorded motion, sound levels, smoke, humidity, and nearby-device signals and gave housing-authority employees remote access to activity data from tenants' homes. The residents allege that the authority accumulated hundreds of millions of data points and retained the information indefinitely.

The residents seek a New Hampshire Superior Court ruling that the nonconsensual collection violated their rights under the state constitution and an injunction stopping the surveillance. Minute-by-minute motion and sound records from the devices can reveal when residents wake, leave, return, receive visitors, and engage in intimate activity. The case is ongoing.