The court said the opinion would only apply in the appeal before it and future cases. It would not be applied retroactively because of its potentially disruptive impact, the court said.
The opinion came in a burglary investigation in Middletown Township in Middlesex County, an affluent town where many residents work on Wall Street. Police traced a cellphone stolen in one of the burglaries to a man who claimed he bought it from the suspect, whom he identified as Thomas W. Earls.
The man told police that Earls kept stolen goods in a storage locker rented with his girlfriend. Shortly afterward, the woman began cooperating with police. Following a search of the locker, police charged Earls, who was still at large, with theft.
They began an emergency search for Earls a short time later after the girlfriend dropped out of sight and police learned she might be in danger of being attacked by Earls for helping the police.
As part of their search, the police asked T-Mobile, the service carrier for the phone that Earls was using, to locate him by tracking his calls. After three attempts to locate Earls, police tracked him to a motel where he was staying with his girlfriend and where he was arrested.
Earls appealed his burglary conviction, asserting that using his cellphone records violated the New Jersey constitution's protections against unreasonable searches and seizures. The Appellate Division of Superior Court ruled against Earls, saying records were not protected.
The Supreme Court overturned that decision and in doing so expanded the privacy protections of New Jersey residents beyond those established under the Fourth Amendment and U.S. Supreme Court decisions.
Legislatures and courts cannot act to weaken constitutional protections of basic rights, but they can tighten them.
Only a few years ago, using cellphone technology to track the movements of criminal suspects posed less urgent constitutional questions, the Supreme Court said. The technology wasn't as powerful, and the ability of authorities to monitor citizens' movements wasn't as precise.
But with the expansion of cellphone networks and towers, such records can now be used to pinpoint a person's whereabouts to within a few yards, the court said.
"It is a very interesting example of how shifting technology may make it important to rethink some of our rules," said Kermit Roosevelt, a constitutional law professor at the University of Pennsylvania Law School. "Is this [additional surveillance options by the government] the cost of the new information technology?"
Federal court decisions afford authorities fairly broad capacity to search records that individuals turn over to third parties, such as bank and telephone records. Under this so-called third party doctrine, individuals have limited expectations of privacy.
It is only when surveillance impinges on personal property that federal courts have imposed a much higher level of scrutiny.
Such was the case in United States v. Jones, when the U.S. Supreme Court ruled unanimously that police, by placing a GPS device on the auto of a person under surveillance without a warrant, violated his private property rights. The majority opinion cut across ideological lines.
In finding that the use of cellphone technology for police surveillance requires a warrant, the state Supreme Court found that people who disclose personal information to telephone companies and other service providers are entitled to keep the information private from the government and, absent a court order, it cannot be released.
Contact Chris Mondics at 215-854-5957 or firstname.lastname@example.org