In a major statement on privacy rights in the digital age, the Supreme Court on Wednesday unanimously ruled that the police need warrants to search the cellphones of people they arrest.

Chief Justice John G. Roberts Jr., writing for the court, said the vast amount of data contained on modern cellphones must be protected from routine inspection.

The old rules, Chief Justice Roberts said, cannot be applied to “modern cellphones, which are now such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude they were an important feature of human anatomy.”

The courts have long allowed warrantless searches in connection with arrests, saying they are justified by the need to protect police officers and to prevent the destruction of evidence, the New York Times reports.

But Chief Justice Roberts said neither justification made much sense in the context of cellphones. On the other side of the balance, he said, is the data contained on the typical cellphone. Ninety percent of Americans have them, he wrote, and they contain “a digital record of nearly every aspect of their lives — from the mundane to the intimate.”

Even the word “cellphone” is a misnomer, he said. “They could just as easily be called cameras, video players, Rolodexes, calendars, tape recorders, libraries, diaries, albums, televisions, maps or newspapers,” he wrote.

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Patrol Blog: SCOTUS Ruling on Cell Phone Searches