Carpenter v. United States was argued on November 29, 2017 and decided on June 22, 2018.

This is a case about “whether the warrantless seizure and search of historical cellphone records revealing the location and movements of a cellphone user over the course of 127 days is permitted by the Fourth Amendment.” While investigating a string of robberies, police obtained a suspect’s cell phone location data from his wireless carrier. Under current law, the police do not need a warrant to obtain such information from the wireless company. Carpenter, who was convicted on multiple counts after the police obtained this data, argues that it amounted to a search that violated his Fourth Amendment rights. The government characterizes the data as unprotected, because it does not say anything about the content of someone’s communication and because Carpenter willingly gave the information to a third party (the cellphone company). 

Case Summary

  • Carpenter v. United States (Note: you will be prompted to create a Street Law store web account in order to download this free case summary.) 

Case Briefs

Oral Argument


News Articles and Resources

  • SCOTUSblog: The justices return to cellphones and the Fourth Amendment: In Plain English
  • Video: Debate on ‘Carpenter v. United States,’ the Fourth Amendment cell-site case