Recent revelations concerning the activities of the National Security Agency (“NSA”) include reports that the NSA and other government agencies have – in secret – routinely collected in bulk the “metadata” associated with millions of telephone users within the United States. While metadata does not include the actual words spoken in a telephone call or written in the body of an email, it often includes transactional data that, in the aggregate, reveals sensitive personal information. Whether and to what extent metadata deserves protection from government surveillance is the subject of intense debate within the legal community, including ongoing litigation by the American Civil Liberties Union.
This week, in its opinion in Riley v. California, the Supreme Court fired a shot across the bow of the NSA and other advocates of warrantless domestic metadata collection. In Riley, the Court held that, when police conduct a warrantless search of a suspect incident to his or her arrest, the Fourth Amendment prohibits police from examining digital information stored on any cell phone found in the suspect’s possession. The Court reasoned that, because modern cell phones store massive quantities of highly personal information, the search of a phone’s digital memory constitutes a much greater invasion of privacy than a typical inspection of physical items recovered from an arrestee’s person. In describing this private information, the Court explained:
“Although the data stored on a cell phone is distinguishable from physical records by quantity alone, certain types of data are also qualitatively different. An Internet search and browsing history, for example, can be found on an Internet-enabled phone and could reveal an individual’s private interests or concerns – perhaps a search for certain symptoms of disease, coupled with frequent visits to WebMD. Data on a cell phone can also reveal where a person has been. Historic location information is a standard feature on many smart phones and can reconstruct someone’s specific movements down to the minute, not only around town but also within a particular building.”
Later in the opinion, the Court further explained that, while it was not ruling on the legality of warrantless pen registers (i.e., remote devices that merely record numbers dialed by a particular caller), that technique cannot be compared to collecting information stored on a modern cell phone, which “typically contain more than just phone numbers.”
In sum, the Court’s opinion in Riley strongly suggests a willingness to find a Fourth Amendment privacy interest in metadata, at least to the extent that data can be aggregated to infer private information about the individual. This outcome may have far reaching consequences in the ongoing debate concerning the proper balance between national security and individual privacy in the United States.