By: Jay Shapiro
Earlier this morning, the Supreme Court of the United States issued its long-awaited ruling in Carpenter v. United States. The question answered by the Court was “whether 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.” In its decision, the Court acknowledged that it was applying the Fourth Amendment “to a new phenomenon” – tracking a person’s past movements through the record of his cell phone signals. The Court found that the acquisition of this information required, in most instances, a warrant supported by probable cause.
The Court was admittedly influenced by the deep detail of information that cell-site data provides, concluding that the data is even more intrusive than that revealed through a GPS device because while people leave their vehicles (and are away from any GPS device the government might secretly install), “they compulsively carry cell phones with them all the time. A cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor’s offices, political headquarters, and other potentially revealing locales.”
While the Court acknowledged that its ruling was narrow and primarily impacts only cell-site information, the reality is that the decision will have significant effects on law enforcement because cell-site location information (CSLI) is a commonly used tool.
Chief Justice Roberts authored the majority, joined by Justices Ginsburg, Breyer, Sotomayor and Kagan. Justice Kennedy filed a dissent, and he was joined by Justices Thomas and Alito. Justices Thomas, Alito and Gorsuch each filed dissenting opinions.