Timothy Carpenter was convicted of robbery after federal prosecutors obtained 127 days of historical cell-site location information (CSLI) from his wireless carriers under the Stored Communications Act. The government did not obtain a warrant supported by probable cause; instead, it used court orders requiring only reasonable grounds to believe the records were relevant to an investigation. The CSLI placed Carpenter near the sites of several robberies and was introduced at trial. Carpenter argued that acquiring this detailed location history was a search under the Fourth Amendment.
Does the government's acquisition of a person's historical cell-site location information from a wireless carrier constitute a Fourth Amendment search requiring a warrant supported by probable cause?
The government's collection of at least seven days of historical CSLI is a Fourth Amendment search. Although business records held by a third party often fall within the third-party doctrine, individuals retain a legitimate expectation of privacy in the whole of their physical movements as captured through long-term CSLI, so the government generally must obtain a warrant supported by probable cause.
Yes. Accessing Carpenter's historical CSLI constituted a search, and the government generally must secure a warrant before obtaining such records.
The Court emphasized that CSLI provides an intimate and comprehensive chronicle of a person's past movements, allowing near-perfect surveillance at minimal cost. Unlike the limited information in older third-party doctrine cases, cell phones are indispensable to modern life and CSLI is generated automatically without any meaningful voluntary exposure by the user. The Court therefore declined to extend Smith v. Maryland and United States v. Miller mechanically to this context. Its ruling was narrow, limited to historical CSLI and not addressing real-time CSLI, tower dumps, or conventional surveillance tools.
Justice Kennedy, joined by Justices Thomas and Alito, argued the records belonged to the carriers and fit squarely within the third-party doctrine. Justice Thomas separately rejected the Katz expectation-of-privacy framework. Justice Alito, joined by Justice Thomas, warned the decision disrupted subpoena and records doctrines. Justice Gorsuch dissented separately, criticizing existing Fourth Amendment doctrine while suggesting a property-based approach might support Carpenter's claim.
Carpenter is a major digital privacy decision that limits the third-party doctrine in the context of modern location-tracking technology. It builds on the Court's concern with pervasive technological surveillance seen in United States v. Jones, 565 U.S. 400 (2012), and Riley v. California, 573 U.S. 373 (2014), while distinguishing Smith v. Maryland, 442 U.S. 735 (1979), and United States v. Miller, 425 U.S. 435 (1976). The case is important because it recognizes that certain sensitive digital records held by companies may still receive Fourth Amendment protection.
United States v. Jones, 565 U.S. 400 (2012) |
Abstain |
Riley v. California, 573 U.S. 373 (2014) |
Abstain |
Smith v. Maryland, 442 U.S. 735 (1979) |
Verified |
United States v. Miller, 425 U.S. 435 (1976) |
Abstain |
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