442 US 735 – 1979
Facts: Woman was robbed; following robbery received threatening phone calls from robber. Upon learning his identity, telephone co. installed pen register at its offices to record numbers dialed from the robber’s house, at the request of the police. The police did not obtain a warrant.
Issue: whether the installation and use of a pen register constitutes a “search” within the meaning of the 4th amendment?
Holding: A pen register is not a search because the “petitioner voluntarily conveyed numerical information to the telephone company” and no warrant is required. He assumed risk of disclosure, it would be unreasonable for him to expect his phone records to remain provide.
Reasoning: Since the defendant had disclosed the dialed numbers to the telephone company so they could connect his call, he did not have a reasonable expectation of privacy in the numbers he dialed. And if he did have an expectation of privacy, it wasn’t reasonable.
- The court said difference between disclosing the numbers to a human operator or just the automatic equipment used by the telephone company results in the same lack privacy expectations.
- The Smith decision left pen registers completely outside constitutional protection. If there was to be any privacy protection, it would have to be enacted by Congress as statutory privacy law.
Dissents: such a list may reveal the identities of the persons and places called, revealing the most intimate of details/just because they know phone co. monitors calls internally doesn’t mean they expect this info to be made available publicly or to the gov/privacy expectations are legit w/in meaning of Katz depends not on risks an individual can be presumed to accept when imparting info to 3rd parties, but on the risks he should be forced to assume in a free society.