The nation's highest court made an emphatic stand Monday for safeguarding privacy and civil liberties in the digital age.

The U.S. Supreme Court unanimously ruled that police violated constitutional protections against unreasonable search and seizure by planting a Global Positioning System device on a suspect's vehicle without a warrant.

This won't be the final word as the courts try to reconcile 18th-century legal principles with 21st-century technology, but it is a significant baseline.

While all nine Supreme Court justices sought to limit police power to track people with GPS devices, there was a 5-4 split on the rationale for the decision.

The slim majority signed on to a narrower ruling that said the problem was that police put the GPS tracker on private property – the Jeep Grand Cherokee of the owner of a Washington nightclub suspected of being part of a drug ring. Police monitored his movements for 28 days and used the evidence to convict him of conspiring to sell cocaine.

The ruling could complicate investigations for law enforcement agencies, which are increasingly relying on high-tech surveillance of suspects. The Obama administration argued that GPS trackers are important to drug and terrorism cases, but was wrong to say they aren't that intrusive. The potential for abuses are so vast that having to show probable cause and get a search warrant in most cases doesn't seem like too much to ask.

Four justices wanted the court to go further in addressing what reasonable expectations of privacy ought to be when there are ever more sophisticated ways to monitor people's whereabouts, and when private companies and public agencies are gathering more and more information about people.

In that opinion, Justice Samuel Alito noted that closed-circuit cameras are "ubiquitous" in some places, that many motorists use electronic toll passes and that phone companies can now track the locations of 300-million-plus cellphones and other wireless devices in use in the United States.

In his majority opinion, Justice Antonin Scalia conceded that the ruling put off "thorny problems" for another day, but wrote that there was "no reason for rushing forward to resolve them."

That day could come very soon. Justices should embrace the chance to further settle the law in this area. All these high-tech, mobile devices make life more convenient. We shouldn't have to sacrifice too much privacy to use them.

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