(CNN) -- The Supreme Court was at odds Tuesday in trying to balance the level of privacy cell phone owners deserve with legitimate concerns of law enforcement.
In oral arguments, the justices tackled the collision of a fundamental constitutional right with omnipresent technology reshaping personal communications, and in many cases, society.
The issue: when and whether police must obtain a warrant to search data on the cell phone of a person under arrest.
What was clear after two hours was that strict constitutional rules favoring one side or the other were not likely to emerge from a seemingly divided and cautious court again examining Fourth Amendment protections in an evolving area of criminal investigation.
Still, potentially far-reaching rulings are expected in June.
The justices offered tough questions to lawyers involved in appeals involving suspects in Massachusetts and California convicted, in part, after phone numbers, text messages, photos and addresses obtained from personal electronic devices linked them to criminal drug and gang activity.
The search cases give the justices a timely opportunity to reenter the public debate over the limits of Americans' privacy rights, with a focus on the ubiquitous cell phone and its vast storage of information and video.
A January Pew Research Center survey found more than 90-percent of Americans now own or regularly use a cellphone, and 58-percent have a more sophisticated smartphone.
They have become the most quickly adopted technology in history. An estimated 6 of the world's 7 billion people have access to the mobile devices, according to the United Nations.
The two criminal cases before the high court present a complex mix of issues to be explored, in the larger context of the popular cell phone and other digital devices. Among the questions:
-- Should law enforcement have near unfettered, warrantless access to possibly incriminating, even embarrassing, digital evidence-- or should exceptions be created?
-- How are searches of cellphones "incident to arrest" different from wallets, purses, briefcases, dairies, compact discs, even vehicle glove compartments?
-- Should other current and future digital devices receive similar legal protections, such as tablets, laptops, separate global positioning systems (GPS) devices, and wearable cameras?
-- What kinds of information are subject to an initial electronic search-- caller ID, call records, contacts list, photos, video -- and how far can police go to thwart encryption devices that are a feature of many newer models?
Lower court judges nationwide have been left divided over how to apply a 40-year-old high court precedent, which allows searches of items a suspect possesses after arrest.
Searches of homes generally require warrants and are given greater constitutional protection than searches of a vehicle or a person out in the public.
Of the two cases addressed by the high court, David Riley's attracted the most scrutiny. He was detained in 2009 for having an expired vehicle registration and driving with a suspended license. When authorities impounded the Lexus, loaded weapons were found hidden under the hood.
After the college student's subsequent arrest, San Diego police looked at his smartphone. Text messages, contacts and video in the touch-screen device led officers to believe Riley had organized crime connections, and a photograph of another vehicle owned by the suspect was linked to an earlier drive-by shooting.
He was convicted in state court and received a 15-year jail sentence.
Separately, Brima Wurie was arrested in 2007 for selling two packets of crack cocaine. He had an old-style flip phone in his pocket, and police in Boston used call logs on the device to trace his real home address, after the suspect gave a bogus one.
There, officers with a search warrant found more drugs, a weapon and ammunition. Wurie was later convicted in federal court and is serving 22 years behind bars.
In neither case did police seek a warrant before the phones were searched. One appeals court upheld Riley's conviction, and another tossed out Wurie's.
During arguments Riley's lawyer Jeffrey Fisher told the justices that giving police too much discretion here "will fundamentally have changed the nature of privacy that Americans fought for at the founding of the Republic and that we've enjoyed ever since."
"Well, including the criminals who are more dangerous, more sophisticated, more elusive with cell phones," replied Justice Anthony Kennedy. "That's the other side of this."
A key divide among the bench was whether cellphones really were different.
"Practically speaking, a person can only carry so much on their person. That is different because carrying a billfold of photographs is a billfold of photograph," said Justice Sonia Sotomayor. "But now we're talking about potentially thousands, because with digital cameras people take endless photos and it spans their entire life. You don't see a difference between the two things?"
Calling it a "nervous concern," Justice Ruth Bader Ginsburg worried police could potentially search anybody's electronic devices if they are stopped for any reason-- "that the "cell phone is fair game no matter what the crime, no matter how relatively unimportant the crime. Is it all misdemeanors that opens the world to the police," she asked.
"So I don't understand why we cut the warrant out of this picture," she added later.
Even Justice Antonin Scalia, traditionally supporting of police procedures, said the idea of searching a person's smartphone for a seat belt violation was "absurd."
The Constitution's Fourth Amendment protects against "unreasonable searches and seizures."
But the high court has repeatedly affirmed the government's discretion to conduct warrantless initial pat-downs and searches of people and vehicles -- to ensure officers' safety and prevent destruction of evidence.
That included a 1973 ruling upholding the police search of a suspect's crumpled cigarette box, where heroin capsules were discovered. The motorist had first been stopped on suspicion of driving on a suspended license in Washington, D.C.
Similar law enforcement searches can include other closed containers, such as wallets and address books, even if it is not initially apparent the items are contraband or dangerous.
But privacy advocates and defense attorneys argue that portable, easily storable technology makes these appeals different.
The high court has been the source of jokes over the years over the perception they are technological Luddites, shunning cameras in court-- and computers and email for typewriters and human messengers. But the justices as a whole are voracious digesters of information, and displayed varying amounts of aptitude at the emerging digital society. Yet even 75-year-old Justice Stephen Breyer could not help poking fun at his old-school ways.
"By the way, GPS information, I don't want to admit it, but my wife might put a little note in my pocket: Steven, remember, turn right at the third stoplight, proceed three blocks forward," he said at one point to courtroom laughter.
The cases are U.S. v. Wurie (13-212) and Riley v. California (13-132).
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