Carpenter v. United States: How Many Cell Phone Location Points Constitute a Search Under the Fourth Amendment?

In Carpenter v. United States, the Supreme Court will decide whether the government’s acquisition of a suspect’s cell site location information (“CSLI”) during an ongoing criminal investigation is a “search” under the Fourth Amendment, and thus requires a showing of probable cause to obtain a warrant. This opinion will have future consequences for Americans and their privacy interests as cell sites continue to be built and CSLI records increasingly contain more private information about cell phone users. This commentary argues that that the necessity of owning and using cell phones renders past tests obsolete. With wavering, subjective expectations of what information is actually private in society today, the Court should thus create a new test that makes a prescriptive claim about expectations of privacy and compares newer technologies with older ones.

The Court should hold that obtaining CSLI records without a warrant is an unreasonable search under the Fourth Amendment.