In March 1976, a Baltimore woman reported to police that she had been robbed. She provided the police with a description of the robber as well as of a vehicle she believed to be his—a 1975 Monte Carlo. Soon afterwards, she began to receive threatening phone calls from a man identifying himself as the robber. A week and a half after the robbery, police saw a man matching the description provided by the victim driving a 1975 Monte Carlo near the scene of the crime. They noted the license plate number, and found that the car was registered to Michael Lee Smith.
Without seeking a warrant, the police then asked the phone company to install a “pen register” at its offices to create a record of all numbers dialed by Smith. After finding that Smith was indeed calling the victim, police obtained a warrant to search his home, found other evidence of phone calls to the victim, and arrested Smith.
Smith sought to exclude the evidence from the pen register, arguing to the Criminal Court of Baltimore that its use without a warrant violated his Fourth Amendment right against unreasonable searches and seizures. The court, however, found no Fourth Amendment violation. After an appeals court reached the same conclusion, the Supreme Court agreed to hear the case.
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.
Nojeim argued that “If strict application of the doctrine ever served us well, it no longer does, leading to absurd results. This is particularly true in an age where so much more information is communicated through intermediaries.” Kerr countered by stating that “I think that the much-maligned third-party doctrine is a critical tool for applying the Fourth Amendment to new technologies in some cases, but that it should not be extended to all cases ... Importantly, my defense of the third-party doctrine implies an important limit: The doctrine should apply when the third party is a recipient of information, but it should not apply when the third party is merely a conduit for information intended for someone else.”