Carpenter v. United States

Case Name: Carpenter v. United States, ___ U.S. ___, 138 S.Ct. 2206, 201 L.Ed.2d 507 (2018)
Chief Justice: John Roberts
Question: Does accessing historical cell phone records constitute a 'search' under the Fourth Amendment?

Cell Phone Usage in the U.S.:
- 396 million cell phone service accounts in a country of 326 million people.
- Cell phones connect to radio antennas called "cell sites" for functionality.
- Cell sites can be on towers, light posts, buildings, etc., and divide regions into sectors with several antennas.
Cell-site Location Information (CSLI):
- Generated every time a cell phone connects to a cell site, creating time-stamped records.
- The precision of CSLI increases with greater concentrations of cell sites, particularly in urban areas.
- Wireless carriers collect and store CSLI for business use, including finding weak network spots and roaming charges.

In 2011, police arrested suspects involved in a series of robberies.
The FBI obtained cell phone records from the suspects, including defendant Timothy Carpenter.
The Stored Communications Act allows the government to compel disclosure of telecommunication records if reasonable grounds are shown.
Court orders were issued for Carpenter's MetroPCS and Sprint records covering 127 days and 2 days, respectively.
The government retrieved 12,898 location points averaging 101 data points per day, leading to Carpenter's conviction.

The court ruled that accessing CSLI constitutes a search under the Fourth Amendment, and thus, a warrant is required.
Privacy Expectations:
- Individuals have a reasonable expectation of privacy in their physical movements captured through CSLI.
- The nature and comprehensiveness of the information collected infer deep personal privacy implications.
- Unlike traditional surveillance, CSLI offers insights into personal lives through movements: familial, political, religious affiliations, etc.
Distinction from Third-Party Doctrine:
- The majority declined to extend the third-party doctrine from cases like Smith v. Maryland, asserting the unique nature of cell phone location information.
- Unlike other records shared with third parties, CSLI reflects comprehensive data collected involuntarily during normal cell phone usage.

Argued that cell-site records are similar to other business records that can be obtained lawfully.
The Court's ruling deviates from traditional property-based concepts of the Fourth Amendment.

Critiqued the "reasonable expectation of privacy" standard established by Katz as having no grounding in the Fourth Amendment's text.
Advocated reevaluating this test as it leads to unpredictability in interpreting Fourth Amendment rights.

Emphasized that Fourth Amendment protections must be based on property rights rather than abstract privacy expectations.
Suggested a return to traditional understandings of privacy rights, eliminating the Katz influence.

This decision underscores the necessity of warrants for obtaining cell-site records, reflecting broader implications for digital privacy.
Highlights ongoing debates regarding surveillance, privacy rights, and the evolving interpretation of the Fourth Amendment in light of technology.