DIMMER SWITCH FOR HIGH-TECH EYES

High-tech crime fighting through thermal imaging devices was checked by the
United States Supreme Court last week in Kyllo vs. United States (June 11,
2001). A 5-4 majority, speaking through Justice Antonin Scalia, held that
the Fourth Amendment prohibited their freewheeling use to detect homegrown
marijuana, whose signature is high-intensity lamps.

The constitutional issue was simply new wine in old bottles. Order and
liberty are perpetual rivals.

Order without liberty is tyranny. Liberty without order is anarchy, a state
of nature where life is poor, brutish, nasty, and short, as Thomas Hobbes
warned.

The rivalry between order and liberty finds constitutional expression in
the Fourth Amendment prohibition of "unreasonable" police searches and
seizures of "persons, houses, papers, and effects."

That injunction which necessarily arrests the ability of the police to
detect crime is more a mood than a command. Its application is inescapably
subjective, pivoting on the prevailing incidence of crime, the seriousness
of the crime under investigation, and our cultural devotion to citizen
privacy free from government snooping. Without the latter, the joys and
creativity of spontaneity wither, healthy non-conformity shrinks, and
feistiness in opposing government overreaching recedes into docility. An
ounce of community revolutionary fervor is indispensable to a pound of
democracy, but 15 ounces would be dangerous.

In sum, drawing a constitutional balance between order and liberty is more
the art of chiaroscuro than the science of prime colors. And the
development of high-tech law enforcement tools neither heightens nor
lessens the artistic challenge. The Kyllo precedent is emblematic.

An agent of the U.S. Interior Department suspected Danny Kyllo of growing
marijuana in his home. Such indoor cultivation characteristically requires
high-intensity lamps. The associated heat emitted, if detected, gives the
game away.

The agent and a colleague thus employed a thermal imaging device to scan
Mr. Kyllo's home from a parked vehicle on a public street. The imager
converts invisible infrared radiation into images based on temperature
differentials. Black is cool, white is hot, and shades of gray connote
relative differences.

The scan showed that the roof over the garage and a side wall of Mr.
Kyllo's home were hot compared to the remainder of the residence, and
substantially warmer than adjacent homes. That information and related
evidence triggered a magistrate's search warrant, which lead to the
discovery of home marijuana cultivation and Mr. Kyllo's federal indictment
for illegal manufacture.

During pretrial skirmishing, Mr. Kyllo moved to suppress the evidence found
pursuant to the warrant. The Fourth Amendment generally prohibits the
prosecution from relying on information derived from an unconstitutional
search or seizure. According to Mr. Kyllo, the warrantless use of the
thermal imaging device violated the reasonableness standard of the
Amendment; and, the constitutional transgression voided the magistrate's
search warrant.

The Supreme Court agreed, at least as to the first proposition.

Justice Antonin Scalia noted that as interpreted in Katz vs. United States
(1967) and its progeny, the Fourth Amendment safeguards privacy
expectations that society is willing to accept as reasonable. But that
axiom smacks of tautological blather, i.e., saying no more than that
individual privacy enjoys constitutional protection only to the extent
society speaking through its police and legislatures is willing to concede.

The whole purpose of the Constitution with judicial review conducted by
independent judges, however, is to restrain, not to surrender to, majority
will.

The Katz test creates the illusion of Fourth Amendment certitude where
ambiguity is an enlightened necessity and has been applied in practice to
fashion a patchwork of case law.

Thus, aerial surveillance of private homes and surrounding areas does not
constitute a search subject to the Amendment, whereas police monitoring of
a beeper in a private home is.

Justice Scalia and Justice John Paul Stevens writing for the Kyllo
dissenters exchanged thunderbolts of Aristotelian logic over whether the
thermal imaging observations were the functional equivalence of police
presence in the home, and whether a Fourth Amendment demarcation line
should be drawn between "off-the-wall" as opposed to "through-the-wall"
technologies. Justice Stevens, for instance, insisted that imaging was
constitutionally innocuous because the infrared camera did no more than
detect "off-the-wall" heat that had been emitted into the public domain.

But that begs the point. The imaging invaded Mr. Kyllo's privacy by
generating information about the interior of his home and home activities
that he wished to conceal and thus inhibited his behavior. That is why the
Fourth Amendment was concerned. And its enclaves of private space are not
impregnable, but can be overcome by a warrant resting on probable cause of
illegal activity.

What was decisive for Justice Scalia was that the government employed an
investigatory device that was not in general public use to unearth
information about the details of Mr. Kyllo's home which would have been
otherwise unknowable without physical intrusion. A tacit subtheme was the
nature of the crime. If he had been building high-tech missile devices for
North Korea or Iran, the decision would probably have been different.

The Fourth Amendment is intellectually messy, but to pretend it could be
otherwise yet retain its vitality would be a flight into fantasyland.