 This is the VOA Special English Technology Report. The satellite-based global positioning system is a great way to locate places or people. But in January, the United States Supreme Court ruled that law enforcement officials must get approval from a judge before placing a GPS tracking device on a vehicle. The case involved a suspected drug dealer in Washington. Police put a GPS device on his car and tracked his movements for almost a month. That led them to a house with nearly 100 kilograms of cocaine and $850,000 in cash. Antoine Jones was found guilty and sentenced to life in prison. He appealed his case all the way to the Supreme Court. Law professor Christopher Slobogen at Vanderbilt University in Nashville, Tennessee says, Mr. Jones argued that that evidence was obtained illegally because the police did not have a warrant. And his argument was, in essence, that use of the tracking device was an unconstitutional search under the Fourth Amendment to the United States Constitution, which provides that the government may not engage in unreasonable searches and seizures. Mr. Jones claimed that the absence of a warrant made this search unreasonable. And says professor Slobogen, the High Court agreed. All nine members of the court, conservative members, as well as liberal members, decided that the Fourth Amendment was violated in this case. But the ruling only dealt with the physical act of placing the GPS device on the vehicle and tracking Mr. Jones. Justice Antonin Scalia wrote the majority opinion. Justice Scalia said the case did not require the court to decide if electronic monitoring without trespassing onto someone's property is also a violation of privacy. Law professor Renee Hutchins at the University of Maryland says, that is a big question that remains to be answered. Most people have smartphones. A lot of people have cars that have GPS pre-installed so the government doesn't have to do the installation. The installation, which was the hook for Justice Scalia, is already accomplished. We do it voluntarily. Justice Sonia Sotomayor suggested that the court may have to rethink what privacy means in modern society, where people voluntarily give up a lot of personal information. As Professor Hutchins put it, in a world where there's Facebook and GPS on your cell phone and GPS in your car, how should the court be thinking about constitutional protections? For VOA Special English, I'm Carolyn Presuti.