Lyle Denniston writes:
Like many Americans, police forces are quick to adopt new electronic devices, capable of processing a wide range of information despite the small size of many such instruments — some as small as a pack of gum. The Supreme Court is more cautious in the face of advances in technology, preferring to move slowly in settling the new constitutional issues stirred up. Next to test its approach, it appears, will be police use of GPS tracking. One appeal on the issue is already at the Court; another, from the federal government, may not be far behind.
What the Court is now being asked to decide is, first, whether a GPS track is a “search,” under the Constitution’s Fourth Amendment, and when might the continuous monitoring of a track become an invalid search if police do it without having a search warrant. The Supreme Court left that second question open when, in U.S. v. Knotts in 1983, it ruled that police use of an electronic beeper to track a suspect’s trip to a drug lab was not a search. What seems to be newly at issue is the role that the duration of tracking plays in the constitutional equation; the argument is that, the longer the tracking, the more movements are monitored, the greater the potential for invading privacy.
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