JUSTICES HEAR OREGON CASE ON HIGH-TECH SURVEILLANCE

Among the many new tools modern technology has put at the disposal of law
enforcement is the Agema 210 thermal imager, a device officers can point at
a house to measure heat emanating from inside. Police use them because
sometimes a suspicious heat flow can be evidence of criminal conduct.

That was the situation on a winter evening in Oregon in 1992, when federal
officers used an Agema 210 to help them determine that the unusual heat
pattern coming from Danny Kyllo's house was produced by high-intensity
lamps that Kyllo was using to illuminate an illegal indoor marijuana nursery.

Indicted for manufacturing marijuana, Kyllo went to court, challenging the
evidence produced by the thermal imaging device. He asserted that the
officers were required by the Constitution to get a search warrant before
they aimed it at his house.

Lower courts agreed with law enforcement officials that the use of the
thermal imager did not require a warrant, but the Supreme Court decided to
hear Kyllo's appeal, apparently to take its own look at the question of how
much privacy citizens have a right to expect at home in an era when
technology can virtually peer through walls.

The court's precedents connect the warrant requirement to the degree of
privacy a reasonable person would expect in a given situation.

The rule was established in a 1967 case in which the court held that police
needed a warrant to place an electronic eavesdropping device on the outside
of a public telephone booth.

During oral arguments on the case yesterday, Kyllo's attorney, Kenneth
Lerner, attempted to persuade the justices that, if anything, the
expectation of privacy was even greater in one's home, and that the thermal
imaging device, though it does not produce an X-ray-like photograph of what
is going on inside, gives the government so much private information that
its use amounts to "spying."

In generally skeptical questioning from the bench, several of the justices
wondered how different the potential invasion of privacy created by heat
imaging technology might be from the intrusion created by more familiar
devices such as binoculars or night-vision goggles.

Justice John Paul Stevens asked Lerner if the police would need a warrant
before dangling a thermometer from a long pole to measure the temperature
of a rooftop.

"Obviously I don't think that we would prohibit things like thermometers or
watches or things that we typically use in our daily lives," Lerner conceded.

Arguing for the United States, Assistant Solicitor General Michael R.
Dreeben noted that the thermal imager "does not penetrate the walls of the
house, it does not reveal particular objects in the house," but rather
creates a rough picture of "heat gradients" that have already radiated
outside the house. Citizens may not reasonably expect that the heat "on the
exterior surface of their walls" should be kept private, Dreeben said.

"I think there is a reasonable expectation of privacy that what you're
doing in your bathroom is not going to be picked up when you take a bath by
somebody with one of these [thermal imaging devices]," Justice David H.
Souter countered.

Dreeben responded by noting that the images produced by an Agema 210 are
too vague to create such a risk: "What you're doing in your bathroom is not
picked up by the thermal imager," he responded.

Lerner, however, seemed to score a point when he suggested that the
justices should keep the inevitable progress of technology in mind when
they rule on a case involving the relatively murky images generated by
current devices.

"The government's test is really going to lead down a difficult road for
this court," he said. "When will information become . . . specific enough
that it should be protected?"