Carpenter v. United States

When a phone connects to a cell site, it generates time-stamped cell-site location information (CSLI) that is stored by wireless carriers for business purposes. The FBI identified the cell phone numbers of robbery suspects. Prosecutors obtained court orders to get the suspects’ CSLI under the Stored Communications Act, which requires “reasonable grounds” for believing that the records were “relevant and material to an ongoing investigation,” 18 U.S.C. 2703(d), rather than a showing of probable cause. With CSLI for Carpenter’s phone, the government cataloged Carpenter’s movements over 127 days, showing that Carpenter’s phone was near four robbery locations at the time those robberies occurred. After denial of his motion to suppress, Carpenter was convicted. The Sixth Circuit affirmed. The Supreme Court reversed, holding that the acquisition of Carpenter’s cell-site records was a Fourth Amendment search. The Fourth Amendment protects expectations of privacy “that society is prepared to recognize as reasonable” so that official intrusion generally qualifies as a search and requires a warrant supported by probable cause. Historical cell-site records give the government near-perfect surveillance, allow it to travel back in time to retrace a person’s whereabouts. Rejecting an argument that the third-party doctrine governed these “business records,” the Court noted the “world of difference between the limited types of personal information” addressed in precedent and the “exhaustive chronicle of location information casually collected by wireless carriers.” CSLI is not truly “shared” because cell phones are an indispensable, pervasive part of daily life and they log CSLI without any affirmative act by the user. The Court noted that its decision is narrow and does not address conventional surveillance tools, such as security cameras, other business records that might reveal location information, or collection techniques involving foreign affairs or national security. View "Carpenter v. United States" on Justia Law