The U.S. Supreme Court has not yet ruled on Fourth Amendment issues raised by ‘smart meters’ – but there are some early indications of how it would probably rule.

Two U.S. Supreme Court decisions provide an indication of how the Supreme Court might apply the Fourth Amendment when a smart meter case does eventually reach them.  One of the cases, Kyllo v. United States (decided 2001), held that police may not use infrared scanning of a home without first obtaining a search warrant.  The use of infrared technology was held to constitute an illegal search of a home even though there was no physical intrusion into the home at the time.

The Kyllo case relied upon a principle established in the earlier case of Katz v. United States (decided 1967)  that the Fourth Amendment applies to a search conducted without physical intrusion.  The earlier case had to do with wiretapping a phone booth.

Click here for an ABC News analysis of these cases.