Smith v. Maryland Case Brief

Facts of the case

On March 5, 1976, Patricia McDonough was robbed in Baltimore, Maryland. She was able to give the police a description of the robber and the 1975 Monte Carlo she thought the robber was driving. Within a few days, she began receiving threatening phone calls that culminated in the caller telling her to stand on her porch, from where she observed the same Monte Carlo drive past. On March 16, the police observed the car in McDonough’s neighborhood. By running a search on the license plate number, the police learned the car was registered to Michael Lee Smith. The police contacted the telephone company and requested that a pen register, a device that only records numbers dialed, record the numbers dialed from the telephone at Smith’s home. On March 17, the pen register recorded a call from Smith’s phone to McDonough’s home, so the police obtained a warrant to search Smith’s house. During the search, police discovered a phone book with the corner turned down on the page on which McDonough’s name was found. Smith was arrested and placed in a line-up where McDonough identified him as the man who robbed her.In pretrial, Smith filed a motion to suppress the information derived from the installation of the pen register because it was obtained without a warrant. The trial court denied the motion, Smith waived a jury, and the case was submitted to the court with an agreed-upon statement of facts. The court convicted Smith and sentenced him to six years in prison. Smith appealed to the Maryland Court of Special Appeals, but the Maryland Court of Appeals intervened by issuing a writ of certiorari. That court affirmed the conviction and held that there was no expectation of privacy to cover the numbers dialed into a telephone system, so there was no Fourth Amendment violation of the warrant requirement.


The Court determined that petitioner’s U.S. Const. amend. IV rights were not violated. The Court found that petitioner did not have a legitimate expectation of privacy regarding the numbers he dialed on his phone because those numbers were automatically turned over to a third party, the phone company. The Court also ruled that even if petitioner did harbor some subjective expectation that the phone numbers he dialed would remain private, this expectation was not one that society was prepared to recognize as reasonable.

  • Advocates: Howard L. Cardin for the petitioner Stephen H. Sachs Attorney General of Maryland, for the respondent
  • Petitioner: Michael Lee Smith
  • Respondent: Maryland
  • DECIDED BY:Burger Court
  • Location: C and P Telephone Baltimore Headquarters
Citation: 442 US 735 (1979)
Argued: Mar 28, 1979
Decided: Jun 20, 1979
Granted: Dec 4, 1978
Smith v. Maryland Case Brief