Property Rights Foundation of America®
Founded 1994


But warrantless aerial surveillance is still allowed


Thermal Imaging from Outside House is ruled an "Unreasonable Search"

By Carol W. LaGrasse

The United States Supreme Court handed Americans a victory for the Fourth Amendment on June 11 by ruling that it is unconstitutional for police to use thermal imaging from outside a house without a search warrant. The practice has come into use in drug enforcement to detect unusual amounts of heat emanating from a house, because that is characteristic of the use of halide lamps to grow marijuana.

Justice Antonin Scalia delivered the 5-4 opinion of the court, joined by two GOP appointees, Justices David H. Souter and Clarence Thomas, and two Democratic appointees, Justices Stephen Breyer and Ruth Bader Ginsburg.

The case, Danny Lee Kyllo versus United States, originated in Florence, Oregon, in 1991, An agent of the U. S. Department of the Interior suspected that marijuana was being grown in Kyllo's home. Without a search warrant, in January 1992, two agents from the Dept. of Interior sat in their vehicle across the street from the house and scanned the triplex where Kyllo lived with a device that detects infrared radiation. Their scan with the thermal imager showed that the roof over the garage and a side wall of Kyllo's home were relatively hot compared to the rest of the home and the other units in the triplex.

Concluding that Kyllo was using heat lamps to grow marijuana, the agent got a search from a federal judge based on the thermal imaging, utility bills, and statements by informants. With the warrant, the agents entered the house and found an indoor growing operation. They arrested Kyllo for growing marijuana.

In court, Kyllo tried to suppress the evidence seized from his home and his case went to the Court of Appeals for the Ninth Circuit. There it was sent back down to the District Court for a hearing about the intrusiveness of thermal imaging.

The District Court ruled that the thermal imaging device "is a non-intrusive device which emits no rays or beams and shows a crude visual image of the heat being radiated from the outside of the house"; it "did not show any people or activity within the walls of the structure" it "cannot penetrate walls or windows to reveal conversations or human activities"; and "(n)o intimate details of the home were observed."

The Court of Appeals initially reversed this ruling, but reversed itself, ruling that Kyllo has shown no expectation of privacy because he had made no attempt to conceal the heat escaping from his home, and even if he had, there was no reasonable expectation of privacy because the imager "did not expose any intimate details of Kyllo's life," only "amorphous 'hot spots' on the roof and exterior wall."

The U. S. Supreme Court reversed the decision of the Court of Appeals. Justice Scalia's decision pointed out that the Fourth Amendment provides that "(t)he right of the people to be secure in their persons, houses, papers, and effects, against unreason able searches and seizures shall not be violated." It cited a 1961 ruling, Silverman v. United States, ruling, "At the very core" of the Fourth Amendment "stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion." It held that with few exceptions, the question whether a warrantless search of a home is reasonable and hence constitutional must be answered no.

The decision discussed at length the change in technology availing the government of visual surveillance, and the historic tie of visual surveillance to trespass. However, the court observed, visual surveillance has been historically lawful, because the eye cannot be guilty of trespass. The decision referred back to the 1986 Ciraolo case where the Supreme Court ruled that aerial surveillance with the naked eye was permissible without a search warrant, even if the police were looking at plants growing within the back yard, which known legally as being within the "curtilage" of the home.

In his discussion of the effect of the evolution of technology on privacy rights, Justice Scalia stated that technology enabling human flight has uncovered portions of the house and its curtilage that once were private. But, he held, the Kyllo case had to confront the limits on the power of technology to shrink the realm of guaranteed privacy.

What the court concluded is that a search is permissible without a search warrant if the surveillance was normally available to the public without additional technology. Thus, looking down from an airplane is permissible, but using an eavesdropping device is not.

The distinction that "off-the-wall observations" could be permissible while "through the wall" surveillance could be impermissible would lead to a trap as technology advances. The court held that any other approach "would leave the homeowner at the mercy of advancing technology-including imaging technology that could discern all human activity in the home."

The ruling also refuted the position that non-intimate details inside the home are not protected by the Fourth Amendment. The decision said, "(T)here is certainly no exception to the warrant requirement for the officer who barely cracks open the front door and sees nothing but the nonintimate rug on the vestibule floor. In the home, our cases show, all details are intimate details, because the entire area is held safe from prying government eyes."

"Where, as here, the Government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a 'search' and is presumptively unreasonable without a warrant," the Supreme Court ruled.

Although this decision represents a victory for privacy rights, the reasoning seems strained and still leaves the property owner with a miserly interpretation of the Fourth Amendment's guarantee of the right of privacy. The footnotes of this case go into a discussion of technology that is pertinent to privacy of the homeowner outside his home, in the curtilage of the home. The discussion of the Ciraolo case hinges on the holding that "In an age where private and commercial flight in the public airways is routine, it is unreasonable for respondent to expect that his marijuana plants were constitutionally protected from being observed with the naked eye from an altitude of l,000 feet." The ruling in Kyllo points out that the focus of the question about technology is on "otherwise-imperceptibility" of activities to police or fellow citizens. But one may ask, when will infrared sensor technology and other snoop technologies become common public usage, and the decision be subsequently narrowed by a future Supreme Court?

The Ciraolo and Kyllo rulings leave little protection for property owners from government aerial surveillance to detect exterior building code and zoning violations. The digitalization of photographic aerial fly-overs through GIS technology makes possible an efficiency of enforcement undreamed of when zoning and building codes were conceived. The dismantling of building and zoning codes to where they deal only with public health, safety and nuisance issues has become more urgent than ever.

- Carol W. LaGrasse
June 16, 2001

Back to:
Privacy - National Oregon State Index PRFA Home Page

© 2001 Property Rights Foundation of America®
All rights reserved. This material may not be broadcast, published, rewritten or redistributed without written permission.