Skip to Content

July 1, 2018 | Adriana Aguilera

Carpenter v U.S.–The Executive Summary and Analysis

Cell phones are an integral part of everyday life, so integral that when you feel for your phone in your pocket and notice it is missing, you may have a moment of panic. They act as a camera, watch, navigation system, and can help you quickly solve a debate with a Google search, easily conducted on internet-enabled smartphones. Not to mention, the ability to text or call nearly anyone you desire to let them know you will be late for dinner or a meeting. However, Carpenter v. U.S. is not about a cell phone. As Chief Justice Roberts said, “It is about a detailed chronicle of a person’s physical presence compiled every day, every moment, over several years.”

Constantly looking for the best signal possible, cell phones access the closest wireless network even when not in use. Every time the device connects to a cell site, it creates a data point, cell-site location information (CSLI). CSLI is stored by wireless companies who use the information for various purposes, including identifying weak spots in their own network.

When Timothy Carpenter was identified as a robbery suspect, prosecutors obtained a court order pursuant to the Stored Communications Act to access CSLI from Carpenter’s wireless carriers. The Stored Communications Act permits the Government to access telecommunications records when it has “reasonable grounds” for believing the information is important to an ongoing investigation, a much lower standard than the “probable cause” required for a warrant. In total, prosecutors received 129 days of CSLI from Carpenter’s wireless carriers, which produced 12,898 individual location points, an average of over 100 per day. This information was used to convict Carpenter who appealed his conviction arguing that the Government conducted a warrantless search in violation of the Fourth Amendment when they accessed the CSLI.

In a 5-4 decision, the Supreme Court held that that the Fourth Amendment requires law enforcement to obtain a warrant before accessing CSLI. Despite the Court referring to the opinion as “narrow,” the decision has been called a groundbreaking expansion of privacy rights in the digital era. The Fourth Amendment protects against “unreasonable searches and seizures.” As technology has advanced, the Fourth Amendment has expanded to protect an individual’s reasonable expectation of privacy. The Supreme Court previously held that recording and compiling phone numbers dialed from a landline was not a search entitled to Fourth Amendment protection but determined that CSLI is “qualitatively different” and that “cell phone location information is detailed, encyclopedic, and effortlessly compiled,” likening CSLI to GPS tracking. The Orwellian fear that “Big Brother is watching” via CSLI is reflected in the Court’s opinion, noting that, “…when the Government tracks the location of a cell phone it achieves near perfect surveillance as if it has attached an ankle monitor to the phone’s user.” The Court determined that Carpenter had a reasonable expectation to privacy in his physical movements tracked via CSLI, and that the Government needed a warrant prior to accessing this information.

What the Carpenter opinion will mean is yet to be determined and the Court seems weary of its precedent explicitly stating it does not affect information collection involving national security, but the Twittersphere is abuzz with ideas for its application. Users from different backgrounds believe this decision will have implications for mass surveillance including facial recognition technology. Others just seem happy that the Supreme Court, sometimes criticized for being technophobic, is willing to expand privacy rights in the wake of new technology. Either way, this is a step in the right direction for those concerned about their right to privacy in a world where it is increasingly easy to chronicle an individual’s location.