The U.S. Supreme Court ruled on Monday that a man's conviction for a drug crime had to be overturned because the police violated the Fourth Amendment when they gathered key evidence against him. The Fourth Amendment prohibits unreasonable search and seizure and the justices said that the police had not correctly followed the instructions of a search warrant when they attached a GPS surveillance device to the drug crime suspect's car.

The justices left for another day the issue of GPS surveillance in general and where the line might be drawn between reasonable surveillance and unreasonable and unconstitutional "Big Brother" surveillance. Electronic surveillance is becoming more commonplace as nearly everything people do can leave an electronic trail. From e-mails, to credit card use, to GPS in phones and cars, it is not hard to track someone down or to see where they went or where they are going.

How much the police can use this information in building criminal cases against people was not decided by the justices. The justices based their decision to overturn the man's conviction on the fact that the police had put the tracking device on the car in the wrong state after too many days had passed. If the police had followed the warrant it is unknown if the case still would have been appealed that far and whether the same result would have occurred.

The justices put off deciding those questions for the next case.

Source: The Washington Post, "Supreme Court: Warrants needed in GPS tracking," Robert Barnes, Jan. 23, 2012