In its 1979 decision in Smith v. Maryland, the Supreme Court ruled in favor of the government, observing that “this Court consistently has held that a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.” The Smith ruling also made reference to another Fourth Amendment case decided three years earlier, United States v. Miller, that involved warrantless government access of a suspect’s bank records. In Miller, the Supreme Court had also found in favor of the government, writing:
The depositor takes the risk, in revealing his affairs to another, that the information will be conveyed by that person to the Government. This Court has held repeatedly that the Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities, even if the information is revealed on the assumption that it will be used only for a limited purpose and the confidence placed in the third party will not be betrayed.
The Miller and Smith decisions solidified what has since become known as the third-party doctrine. Under that doctrine, if you voluntarily provide information to a third party, the Fourth Amendment does not preclude the government from accessing it without a warrant. More succinctly, as the Court wrote in Smith, you have “no legitimate expectation of privacy” from warrantless government access to that information.
Much has changed since the 1970s. Today, being engaged in the world involves using the Internet, mobile phones, apps, cloud-based services, GPS, and other technologies that leave enormous amounts of information in the hands of third parties. Even before the NSA documents leaked by Edward Snowden started appearing on the home pages of the world’s news sites, there was a robust discussion about the continued suitability of the third party doctrine.
One of the most important recent Supreme Court privacy decisions, the United States v. Jones ruling issued in 2012, involved GPS tracking performed directly by the government, without a third party intermediary. (That case, which the government lost, turned on the government’s physical intrusion onto private property, without a valid warrant, to attach a GPS tracker to a suspect’s car.) Yet Justice Sotomayor used her concurrence in Jones to examine privacy more broadly and telegraph her discomfort with the third-party doctrine:
More fundamentally, it may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties. This approach is ill suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks ... I would not assume that all information voluntarily disclosed to some member of the public for a limited purpose is, for that reason alone, disentitled to Fourth Amendment protection.
There are varying views in the legal community regarding the third-party doctrine. Consider this August 2012 debate between Greg Nojeim, senior counsel at the Center for Democracy and Technology and George Washington University law professor Orin Kerr.