Carpenter v. United States
- Court
- Supreme Court of the United States (U.S. Supreme Court)
- Decided
- 2018
- Citation
- 585 U.S. 296 (2018)
- Standard applied
- Fourth Amendment — third-party doctrine and historical CSLI
What the court held
The government's acquisition of historical cell-site location information from a wireless carrier is a Fourth Amendment search, and generally requires a warrant. An order under 18 U.S.C. § 2703(d) of the Stored Communications Act, which rests on a “reasonable grounds” showing, falls short of probable cause and is not a permissible mechanism for obtaining those records.
Why
The Court declined to extend the third-party doctrine of Smith and Miller to cell-site records, treating them as qualitatively different from dialled digits and bank statements because they are generated automatically, retained cheaply and indefinitely, and map the whole of a person's physical movements. Location data of that kind implicates the expectation of privacy recognised in Jones, and the fact that a carrier holds it does not defeat that expectation. The Court described its decision as a narrow one, expressly reserving real-time CSLI, tower dumps, conventional surveillance techniques, and national-security collection.
“Given the unique nature of cell phone location information, the fact that the Government obtained the information from a third party does not overcome Carpenter’s claim to Fourth Amendment protection.”
Our reading — not the court’s words
Why this matters in practice
Carpenter is where the aggregation theory became law, and its reach is still being litigated across every category of automatically generated record a phone leaves behind. The practical discipline it imposes on an investigator or examiner is to ask what legal instrument produced each dataset in a case file, because a § 2703(d) order that was routine before 2018 may now be the defect that costs the evidence. Note what the Court reserved: the opinion is narrower than the slogan “location data needs a warrant” suggests.
This paragraph is Legal Cyber Academy’s editorial assessment of the decision’s practical importance. The court said none of it. For what the court actually said, read the opinion.
Additional detail
Tags: CSLI · third-party doctrine · Stored Communications Act
Cited 1,227times in CourtListener’s corpus at the time this entry was compiled. Treat it as a rough measure of influence, not of correctness.
Other decisions on fourth amendment and privacy & surveillance
- United States v. JonesSupreme Court of the United States · 2012Attaching a GPS tracking device to a vehicle and using it to monitor the vehicle's movements constitutes a search within the meaning of the Fourth Amendment. Th…
- Riley v. CaliforniaSupreme Court of the United States · 2014Police generally may not search the digital contents of a cell phone seized incident to an arrest without a warrant. The search-incident-to-arrest exception, wh…
- United States v. WarshakCourt of Appeals for the Sixth Circuit · 2010A subscriber has a reasonable expectation of privacy in the contents of e-mails stored with, or sent or received through, a commercial internet service provider…
- In re Application of the United States for Historical Cell Site DataCourt of Appeals for the Fifth Circuit · 2013Court orders authorised by the Stored Communications Act compelling cell-phone service providers to produce subscribers' historical cell-site information are no…
- United States v. GrahamCourt of Appeals for the Fourth Circuit · 2016Sitting en banc, the Fourth Circuit held that a cell-phone user has no reasonable expectation of privacy in historical cell-site location information held by hi…
- United States v. DavisCourt of Appeals for the Eleventh Circuit · 2015Sitting en banc, the Eleventh Circuit held that a court order under § 2703(d) of the Stored Communications Act compelling a telephone company to produce its bus…
Summarised from the opinion as retrieved from CourtListener. Reference material, not legal advice. Back to the repository.