Today the U.S.S.C. ruled in Carpenter v. United States that law enforcement accessing data to track cell phone locations must first get a search warrant.
Timothy Carpenter was a suspect in a series of robberies of Radio Shack and T-Mobile stores in Detroit. Law enforcement got court orders under the Stored Communications Act to obtain his cell phone records. They were able to obtain 12,898 location points cataloging Carpenter’s movements over 150 days. Carpenter moved to suppress the evidence at trial and his motion was denied. The Sixth Circuit affirmed his conviction. The USSC reverses.
Having found that the acquisition of Carpenter’s CSLI was a search, we also conclude that the Government must generally obtain a warrant supported by probable cause before acquiring such records. Although the “ultimate measure of the constitutionality of a governmental search is ‘reasonableness,’” our cases establish that warrantless searches are typically unreasonable where “a search is undertaken by law enforcement officials to discover evidence of criminal wrongdoing.” Vernonia School Dist. 47 v. Acton, 515 U. S. 646, 652–653 (1995). Thus, “[i]n the absence of a warrant, a search is reasonable only if it falls within a specific exception to the warrant requirement.” Riley, 573 U. S., at ___ (slip op., at 5).
The Government acquired the cell-site records pursuant to a court order issued under the Stored Communications Act, which required the Government to show “reasonable grounds” for believing that the records were “relevant and material to an ongoing investigation.” 18 U. S. C. §2703(d). That showing falls well short of the probable cause required for a warrant. The Court usually requires “some quantum of individualized suspicion” before a search or seizure may take place. United States v. Martinez-Fuerte, 428 U. S. 543, 560–561 (1976). Under the standard in the Stored Communications Act, however, law enforcement need only show that the cell-site evidence might be pertinent to an ongoing investigation—a “gigantic” departure from the probable cause rule, as the Government explained below. App. 34. Consequently, an order issued under Section 2703(d) of the Act is not a permissible mechanism for accessing historical cell-site records. Before compelling a wireless carrier to turn over a subscriber’s CSLI, the Government’s obligation is a familiar one—get a warrant.