WASHINGTON – The Supreme Court invoked visions of an all-seeing Big Brother and satellites watching us from above. Then things got personal Tuesday when the justices were told police could slap GPS devices on their cars and track their movements, without asking a judge for advance approval.

The occasion for all the talk about intrusive police actions was a hearing in a case about whether the police must get a search warrant before using GPS technology to track criminal suspects. The outcome could have implications for other high-tech surveillance methods as well.

The justices expressed deep reservations about warrantless GPS tracking. But there also was no clear view about how or whether to regulate police use of the devices.

The justices were taken aback when the lawyer representing the government said police officers could install GPS devices on the justices’ cars and track their movements without a warrant. To get a warrant, investigators need to convince a judge that there is reason to believe a suspect is involved in criminal activity.

“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?” Chief Justice John Roberts said.

Not only that, government lawyer Michael Dreeben replied, but FBI agents wouldn’t need a warrant either if they wanted to rummage through the justices’ trash, use a low-tech beeper to track them or tail them around the clock with a team of agents. Dreeben said the court has previously ruled that people have no reasonable expectation of privacy in those circumstances.

Justice Samuel Alito captured the essence of the court’s concern when he said, “With computers around, it’s now so simple to amass an enormous amount of information. How do we deal with this? Just say nothing has changed?”

Justice Stephen Breyer alluded to George Orwell’s novel “1984” when he said surveillance in the past depended on human beings and their sometimes flawed memories. But computers don’t have that problem, he said.

“The question that I think people are driving at, at least as I understand it and certainly share the concern, is that 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,” Breyer said.

But Dreeben said it would be better for lawmakers rather than judges to set limits. Dreeben said the concerns expressed Tuesday were similar to those in the earlier high court case. Thirty years ago, Dreeben said, “Beeper technology seemed extraordinarily advanced.”

The GPS issue arose after the federal appeals court in Washington threw out the drug conspiracy conviction of nightclub owner Antoine Jones. FBI agents and local police did not have a valid search warrant when they installed a GPS device on Jones’ car and collected travel information for a month.