The Supreme Court justices are with it. They’re hip. They understand the Facebook, and the Twitter, and the Fitbit. During oral arguments in a crucial privacy case involving cell phones, they tried to prove it.

After being widely mocked for their performance in a recent copyright case involving a company that allows customers to watch cable television over the Internet, the Justices seemed particularly eager to show that just because they still communicate through written notes, it doesn’t mean they’re tech illiterate. Faced with the question of whether or not police should have to get a warrant before searching a smartphone, the Justices insisted they understand the stakes for the Fourth Amendment in a world where Americans carry devices with massive amounts of personal data everywhere they go.

“Most people now do carry their lives on cell phones, and that will only grow every single year as, you know, young people take over the world,” said Justice Elena Kagan, who seemed deeply concerned with the privacy implications of warrantless cell phone searches. “They’re computers. They have as much computing capacity as laptops did five years ago. And ­everybody under a certain age, let’s say under 40, has everything on them.”

Yet with the exception of Kagan and Justice Ruth Bader Ginsburg, most of the Justices seemed to be groping for a balance that would allow police some access to an arrestees’ cell phone without a warrant under certain circumstances. They seemed unsure exactly where to draw the line.

The case began with David Riley, an accused gang member who was picked up for expired tags in 2009. Police found guns in his car, and later at the station, they found photos, videos and text messages indicating gang membership on his phone. They used some of that evidence to tie him to an earlier shooting. Riley is arguing that searching his phone without a warrant violated his constitutional rights against search and seizure. The state of California and the U.S. government are arguing that cops should be allowed to treat cell phones should like anything else found in your pocket, even though they contain massive amounts of personal information.

“Why can’t you just put the phone on airplane mode?” Justice Sonia Sotomayor asked when Deputy Solicitor General Michael Dreeben warned that encryption and remote wipe technology would make it easier for criminals to deny police access to evidence even after arrest. “Airplane mode” is a setting on some cell phones that leaves the device on but cuts off its access to wireless networks. After a back-and-forth, Dreeben said that “I don’t think the Court should find a constitutional ruling” on the possibility that phones will continue to feature airplane mode.

Some of the justices’ efforts to show off their tech skills were not encouraging for privacy advocates who are hoping the court will rule that cops need warrants to scroll through information on your cell phone.

“Could you have a rule that the police are entitled to search those apps that, in fact, don’t have an air of privacy about them?” Chief Justice John Roberts asked. “What about something like Facebook or a Twitter account? There’s no real, there’s no – any privacy interest in a Facebook account is at least diminished because the point is you want these things to be public and seen widely.”

Roberts seemed confused by the difference between being able to see a public status update or a tweet and having direct access to a password-protected social media account through a mobile device – perhaps Anthony Weiner could enlighten him.

Later, Roberts asked whether police could look at a suspect’s Fitbit, which would show how far a suspect had walked, but not reveal deeply personal information.

Justice Samuel Alito seemed the most sympathetic to the government’s argument that police should be able to search cell phones of arrestees, at one point comparing cell phones to a billfold with family photos in it. Alito suggested the possibility of a rule that would allow police to warrantlessly search cell phones for anything that “has a realistic analogue in the pre-digital era.”

Pointing out that a person with 10,000 photographs on their phone would be carrying something that would meet that standard, Justice Stephen Breyer said, “I think there are very, very few things that you cannot find in analogue to in pre­-digital age searches.”

Jeffrey Fisher, Riley’s attorney, tried to persuade the justices that the ubiquity of cell phones, and the amount of information they carry, justifies a warrant requirement. “The modern reality of smartphones is that it is an indispensable item for everyday life of a modern professional and, indeed, most anyone,” Fisher said.

“Well, including the criminals who are more dangerous, more sophisticated, more elusive with cell phones. That’s the ­­that’s the other side of this,” Justice Anthony Kennedy said.

Justice Antonin Scalia, who has sided against the government in Fourth Amendment cases in the past, seemed to be on the fence. He expressed concern that a warrant requirement for a cell phone search might prevent the cops from finding a bomb or discovering an ambush. Later however, he said that should someone be arrested for driving without wearing a seat belt, “it seems absurd that you should be able to search that person’s iPhone.” He suggested a possible rule where police would have to be “reasonably be looking for evidence of the crime of arrest.”

Edward Dumont, California’s Solicitor General, really liked that idea. “We think that that could be a perfectly reasonable ruling,” Dumont said.

Sensing some of her colleagues might be on the fence, Kagan explained why. “It sounds good as a limiting principle, but it ends up you can imagine in every case that the police could really look at everything,” Kagan said.

Kagan and Ginsburg seemed most sympathetic to the idea that police should be required to get a warrant to search a cell phone. Roberts, Sotomayor, Breyer, Kennedy, and Scalia asked hard questions on both sides, but seemed open to a rule that would allow police to search phones without a warrant under some circumstances.

Whatever they decide will have massive privacy implications that will reverberate long after they’re gone, and long after the Internet buzzwords of today have faded from significance.