Washington (CNN) -- When the Supreme Court begins to wonder how evolving law enforcement policies will affect them personally, the government may want to start worrying. That concern was evident in a freewheeling case argued Tuesday over police surveillance.
Government agents used a global positioning system, or GPS, to track a criminal suspect's movements around the clock as he drove in his car around the nation's capital. After a monthlong clandestine operation, the man was arrested and charged with drug trafficking.
A majority of the justices appeared adamant after a one-hour public session that officers should have obtained a warrant before placing the device on the suspect's vehicle. A government lawyer suggested such surveillance could be used on members of the court itself.
"So your answer is yes, you could tomorrow decide that you put a GPS device on every one of our cars, follow us for a month; no problem under the Constitution?" said Chief Justice John Roberts to a government lawyer, as he gestured to his eight colleagues. He seemed surprised at the Obama administration's sweeping assertion.
At issue is whether movement in a vehicle on city streets is "public" in nature.
"With computers, it's now so simple to amass an enormous amount of information," said Justice Samuel Alito. "So how do we deal with this? Do we just say, well, nothing has changed?"
Growing sophistication of electronic devices to monitor the movements of suspects makes this issue ripe for review, since lower courts have disagreed on when such surveillance is permissible without a warrant.
The devices send an electronic signal to a satellite, allowing real-time plotting of someone's whereabouts.
Antoine Jones was a co-owner of Levels, a Washington nightclub. He was suspected of trafficking cocaine on the side, and a joint FBI-D.C. police team covertly attached a GPS device to his Jeep without first obtaining a warrant.
He was eventually tracked to suburban Maryland, where law enforcement officers discovered nearly 100 kilograms of the illegal narcotic, along with about $850,000 in cash. He was later sentenced to life in prison.
The court was being asked to decide whether such surveillance violated the Fourth Amendment and whether in this case it should be considered a "search," a "seizure," or both.
The Constitution says in "the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated."
Government attorney Michael Dreeben met stiff resistance from the court when he suggested police have broad authority to conduct surveillance without first establishing "probable cause," a legal standard requiring a warrant.
Justice Anthony Kennedy: "I have serious reservations about the way in which this (device) was installed."
Justice Antonin Scalia: "When that device is installed against the will of the owner of the car, that is unquestionably a trespass ... an unreasonable search and seizure."
Justice Ruth Bader Ginsburg: "The government's position would mean that any of us could be monitored whenever we leave our homes, so the only thing secure is the home. This is the end point of your argument, that an electronic device, as long as it's not used inside the house, is OK."
Justice Stephen Breyer: "If you win this case then there is nothing to prevent the police or the government from monitoring 24 hours a day the public movement of every citizen of the United States. ... So if you win, you suddenly produce what sounds like '1984'," the futuristic novel of a totalitarian, ultra-control society run by Big Brother.
Dreeben suggested legislatures are the best forum to impose search limits, not the courts -- a suggestion Scalia in particular seemed to embrace. The government lawyer also said the court's current concerns mirror those three decades ago in a case over suspects tracked through less-sophisticated beepers, requiring police to closely follow the vehicle.
"You're talking about the difference between seeing the little tile and seeing a mosaic," Roberts said. "The one gives you information, the other doesn't."
As tough as the court was on the government, they were equally skeptical of some of the sweeping assertions made by Jones' lawyer, Stephen Leckar. Several justices were concerned a broad ruling might hamper police surveillance when they lack probable cause.
"He wouldn't be protected against a surveillance camera that could get information, and is this (GPS) really different in kind from the surveillance camera?" Ginsburg asked.
Justice Elena Kagan offered a real-life example. "If somebody goes to London, almost every place that person goes there is a camera taking pictures, so that the police can put together snapshots of where everybody is all the time. So why is this different from that?"
Leckar replied, "It's pretty scary."
Breyer said such overseas camera surveillance may have helped prevent a recent planned terror attack at a Scottish train station.
The court sought in vain a standard that would allow police to conduct surveillance without infringing on individual rights. Would two hours of surveillance be acceptable? Two weeks? What about tracking devices placed on briefcases or an overcoat? Is use of traffic cameras permissible?
Each example offered brought less and less consensus from the court. The justices have the option of just focusing on this one appeal and this one electronic surveillance technique, or using it as a platform to resolve larger questions over a range of other current or future technologies.
The justices have another pending case they may decide to tackle, from an Oregon inmate who faced similar circumstances. Police there had attached a GPS device to Juan Pineda-Moreno's car while it was parked on his property. Officers then tracked him to a remote marijuana field he was cultivating. He was convicted and sentenced to more than four years behind bars.
Unlike Jones, a federal appeals court in San Francisco ruled this was not a "search" so no warrant was required to place the device on Pineda-Moreno's Jeep Cherokee. His conviction was upheld.
The justices have not yet taken any action on the Oregon appeal, perhaps waiting to resolve the issue with Jones' appeal from Washington.
The current case is U.S. v. Jones (10-1259). A ruling is expected by spring 2012.