The Supreme Court ruled Wednesday that police cannot go snooping through people’s cell phones without a warrant, in a unanimous decision that amounts to a major statement in favor of privacy rights. Police agencies had argued that searching through the data on cell phones was no different than asking someone to turn out his pockets, but the justices rejected that, saying a cell phone is more fundamental. The ruling amounts to a 21st century update to legal understanding of privacy rights. “The fact that technology now allows an individual to carry such information in his hand does not make the...