The Fourth Amendment Third-Party Doctrine, Richard M. Thompson II, Legislative Attorney. June 5, 2014.

“In the 1970s, the Supreme Court handed down Smith v. Maryland and United States v. Miller, two of the most important Fourth Amendment decisions of the 20th century. In these cases, the Court held that people are not entitled to an expectation of privacy in information they voluntarily provide to third parties. This legal proposition, known as the third-party doctrine, permits the government access to, as a matter of Fourth Amendment law, a vast amount of information about individuals, such as the websites they visit; who they have emailed; the phone numbers they dial; and their utility, banking, and education records, just to name a few. Questions have been raised whether this doctrine is still viable in light of the major technological and social changes over the past several decades. Before there were emails, instant messaging, and other forms of electronic communication, it was much easier for the courts to determine if a government investigation constituted a Fourth Amendment “search.” If the police intruded on your person, house, papers, or effects—tangible property interests listed in the text of the Fourth Amendment—that act was considered a search, which had to be “reasonable” under the circumstances. However, with the advent of intangible forms of communication, like the telephone or the Internet, it became much more difficult for judges to determine when certain surveillance practices intruded upon Fourth Amendment rights. With Katz v. United States, the Court supposedly remedied this by declaring that the Fourth Amendment protects not only a person’s tangible things, but additionally, his right to privacy. Katz, however, left unprotected anything a person knowingly exposes to the public. This idea would form the basis of Smith and Miller. In those cases, the Court held that a customer has no reasonable expectation of privacy in the phone numbers he dials (Smith) and in checks and deposit slips he gives to his bank (Miller), as he has exposed them to another and assumed the risk they could be handed over to the government.”