In a huge victory for privacy, the U.S. Supreme Court ruled that law enforcement will need a warrant in order to obtain an individual’s cellphone location data. The 5-4 ruling is a significant stepping stone to establishing a framework which protects Americans from the police taking advantage of their technological information.
Up until the decision, the digital right to privacy has been hazy. When consumers sign up for certain cellphone services and websites, the assumption has been that using such services means that the consumer is implicitly agreeing to give the power to share their data with third parties to cellphone companies. In turn, cellphone companies have provided digital footprints to law enforcement in order to track individuals’ whereabouts.
In Carpenter v. United States, investigators obtained records from cellphone towers spanning approximately 127 days—consisting of 12,898 location points—without a search warrant in their case against Timothy Carpenter. He was sentenced to a prison sentence of 116 years for his part in a string of robberies in Michigan and Ohio.
Lower courts found that no warrant was required since location data fell under the same category as the subpoena of third-party business records. The Supreme Court concluded that the voluntary conveyance assumption behind the third-party doctrine doesn’t hold up with regard to cellphone location information since the user only has to power up the device to be tracked without any affirmative act on their part.
Chief Justice John Roberts, followed by the four liberal justices, wrote that the authors of the U.S. Constitution would have found the blatant invasion of privacy in direct violation of the Fourth Amendment. However, he said that the ruling will not apply to typical means of police surveillance, such as security cameras and matters of national security.
This ruling was the third in recent years in which the court has decided on major cases on how criminal law applies to technology, ruling against law enforcement on each occasion. In 2012, it ruled that a warrant is required to place a GPS tracking device on a vehicle. In 2014, it required police to seek a warrant to search a person’s cellphone’s contents upon the user’s arrest.