NO SPYING ON HEAT WAVES

Personal privacy may be doomed by ever more pervasive technology, but a
divided Supreme Court has staved off that unhappy day for at least a
while.

In a 5-4 decision, the court ruled that it was a search requiring a
warrant when police officers used a heat-sensing device to detect
high-intensity lights to grow marijuana inside Danny Kyllo's home.
Because they detected unnaturally warm spots in Kyllo's garage and
attic, police obtained a warrant and did indeed find more than 100
marijuana plants under grow-lights.

Just how conflicted the court found itself was apparent in the odd
lineups for and against: Justices Antonin Scalia and Ruth Bader
Ginsburg, usually polar opposites, were in the majority and Chief
Justice William Rehnquist, a conservative, and John Paul Stevens, the
court's most liberal justice, were in the minority.

The precedent is important because ever more sophisticated Big Brother
surveillance devices are in the works. The distinction that Stevens
drew, between "off-the-wall" as opposed to "through-the-wall"
surveillance, may one day be technologically irrelevant.
Through-the-wall radar and ultrasound technology is already available to
police, and this decision has at least raised the bar for use of such
devices.

Scalia argued that any evidence about the interior of a private home
that could not have otherwise been legally gathered without physical
entry was an illegal search under the Fourth Amendment.

However, even Scalia seemed to pull his punch and open the door to
further mischief by using as one of his criteria the fact that the
thermal imaging device was not widely available to the public. Just
because a surveillance device can be easily and freely acquired doesn't
mean the right to privacy should be diluted.

Kyllo is not off the hook. His case now goes back to a lower court to
determine whether the other grounds -- heating bills, an informant's tip
- -- were adequate for obtaining the warrant. And, in the game of cops and
robbers, the need to obtain a warrant for high-tech surveillance is
another procedural step for law enforcement but it is still an important
constitutional protection.

Both the majority and the dissenting justice made reasonable arguments
(Stevens noting that heat waves are in the public domain once they leave
a building), and the decision might have gone either way.

But the majority decision was one that keeps an important constitutional
principle intact in a time much different from the time it was
established.