ALL-SEEING EYE: HIGH COURT CURBS ELECTRONIC SURVEILLANCE

The U.S. Supreme Court's decision in the thermal-imaging case last week
gave comfort to Americans who are concerned that technology is eroding the
Fourth Amendment's guarantee against unreasonable searches by the police.

But Americans shouldn't get too comfortable. Technology keeps changing, and
this issue isn't likely to stay settled for long.

In the case of Kyllo vs. United States, the high court reversed the
conviction of Danny Lee Kyllo for growing more than 100 marijuana plants in
the triplex where he lived in the seaside town of Florence, Ore.

Suspicious that Kyllo was a grower, government agents stationed themselves
on a public street one night and used an Agema Thermovision 210 thermal
imager to determine whether the amount of heat emanating from his home was
consistent with the high-intensity lamps used to grow marijuana indoors.
They did not have a search warrant.

Writing for a 5-4 majority, Justice Antonin Scalia stated that unless a
warrant is obtained, the Fourth Amendment is violated "where government
uses a device that is not in general public use to explore details of a
private home that would previously have been unknowable without physical
intrusion.''

The Kyllo decision seems odd at first: The conservative Scalia wrote an
opinion that would gladden the heart of a modern civil libertarian, while
the court's most liberal justice, John Paul Stevens, wrote a dissent --
joined by three conservatives -- that criticizes the majority for its lack
of judicial restraint in trying to craft "an all-encompassing rule for the
future.''

A core concept of the Fourth Amendment, Scalia noted, is that people are
protected from searches when they manifest a reasonable expectation of
privacy in the object of the search. Put simply, a person couldn't
reasonably expect a passing police officer not to see marijuana plants
growing in his front yard. But he could expect police not to barge into his
closet marijuana farm without a warrant.

Scalia acknowledged that technology has changed the degree of privacy that
people can expect to enjoy -- even on their own property. The Kyllo
decision does not disturb previous court rulings that allow government to
photograph homes from the air, for example, or to go to the telephone
company and read out the phone numbers that a person is dialing.

Stevens, in dissent, saw a distinction between an unwarranted search for
objects (such as heat lamps) behind the walls of a house and the detection
of phenomena (such as large amounts of heat escaping) from the public
domain. The latter does not constitute an unreasonable search, even if
aided by technology, he argued.

Technology keeps changing, and Kyllo vs. United States stopped short of
setting specific limits on the degree to which technology should be
prevented from intruding into private lives. Although this particular fact
pattern was addressed, the overall issue is by no means settled.