U.S. courts or Congress also need to reexamine current law that allows law enforcement agencies to gain access, without a warrant, to digital information shared with a third party, given the amount of digital information people share with online services, he said.
Some recent court cases, including the Supreme Court's 2014 Riley v. California ruling limiting law enforcement searches of mobile phones, have moved privacy law in the right direction, he said.
Posner questioned why smartphone users need legal protections, saying he doesn't understand what information on smartphones should be shielded from government searches. "If someone drained my cell phone, they would find a picture of my cat, some phone numbers, some email addresses, some email text," he said. "What's the big deal?
"Other people must have really exciting stuff," Posner added. "Do they narrate their adulteries, or something like that?"
Smartphones can contain all kinds of information that people don't want to share, including medical information, visits to abortion doctors and schedules for Alcoholics Anonymous meetings, Cole said. "Your original question, 'what's the value of privacy unless you've got something to hide?' that's a very short-sighted way of thinking about the value of privacy," he said.
In the 1960s and '70s, government agencies investigated political figures, in some cases, bugging hotel rooms in search of evidence of affairs, Cole noted. Government misuse of surveillance information is still a risk, he said, and smartphones could be a treasure trove of information.
The U.S. and other governments have a long history of targeting people "who they are concerned about because they have political views and political positions that the government doesn't approve of," Cole said.
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