Carpenter v. United States
In Carpenter v. United States, 138 S. Ct. 2206 (2018), the U.S. Supreme Court held that "the Government conducts a search under the Fourth Amendment when it accesses historical cell phone records that provide a comprehensive chronicle of the user’s past movements." Chief Justice John Roberts wrote the decision for the 5–4 Court.
The Court majority held that:
|“|| As Justice Brandeis explained in his famous dissent, the Court is obligated—as “[s]ubtler and more far-reaching means of invading privacy have become available to the Government”—to ensure that the “progress of science” does not erode Fourth Amendment protections. Olmstead v. United States, 277 U. S. 438, 473-474, 48 S. Ct. 564, 72 L. Ed. 944 (1928). Here the progress of science has afforded law enforcement a powerful new tool to carry out its important responsibilities. At the same time, this tool risks Government encroachment of the sort the Framers, “after consulting the lessons of history,” drafted the Fourth Amendment to prevent. Di Re, 332 U. S., at 595.
We decline to grant the state unrestricted access to a wireless carrier’s database of physical location information. In light of the deeply revealing nature of CSLI [cell-site location information], its depth, breadth, and comprehensive reach, and the inescapable and automatic nature of its collection, the fact that such information is gathered by a third party does not make it any less deserving of Fourth Amendment protection. The Government’s acquisition of the cell-site records here was a search under that Amendment.
- Justice Neil Gorsuch was in the 4-justice minority, but only because he sought to establish Fourth Amendment rights in the right to private property. In a sense, the decision was really 6–3 in protecting privacy, when including his vote in favor of expanding Fourth Amendment rights.