Thermal imaging technology allows police to ascertain if a suspect is growing marijuana in his home by monitoring the escaping heat from the home. Conflicts between the lower courts on whether thermal imaging is sophisticated technology that is intrusive has not been resolved. Most courts rely on Katz v. United States in developing a reasonable inquiry into whether one's privacy has been invaded. The Katz test fails in part because of the second prong of the court's analysis. The second prong of the test states that an impermissible search occurs when a reasonable expectation of privacy is invaded. Consequently, prosecutors rely on the test because they argue there is no reasonable expectation of privacy recognized by society in heat that is escaping from one's home. The use of thermal imaging technology raises questions of whether the use of the imager is permissible under the Fourth Amendment. The Fourth Amendment protects persons from illegal searches. Police are using thermal imagers to fight crime. The technology is aiding the fight against drugs; however, the potential for abuse is great. This technology may destroy basic Fourth Amendment rights. The importance of privacy and the limitations on police searches should remain important in a society that is evolving technologically. The framers of the Constitution insured privacy and limited invasiveness by the police by creating the Fourth Amendment. The Fourth Amendment also was created to protect persons from arbitrary and capricious searches. The framers intended for searches to be based on specific information. Thus the members of society feel security from invasive action by the police. The Katz test can be easily manipulated by the government for their benefit, while infringing on one's Fourth Amendment rights. The author proposes that the courts cannot uphold a test that is nothing more than an estimation of what is considered a reasonable search. Consequently, in order for all members of society to be protected by the Fourth Amendment, Katz should not protect thermal-imaging technology. Rather, the courts should follow the Washington test. In Washington v. Young, the court held that the police use of the thermal imager was "constitutionally offensive" and the court placed limitations on the use of the thermal imager. The court further stated that the surveillance was an intrusive means of observation that exceed the established surveillance limits of the police. Thus, the Washington test should be adopted because it is less likely to be manipulated by the police. The test uses the private affairs of an individual to measure impermissible searches.
Daniel J. Polatsek, Thermal Imaging and the Fourth Amendment: Pushing the Katz Test Towards Terminal Velocity, 13 J. Marshall J. Computer & Info. L. 453 (1995)