Abstract
Suppose the government was capable of detecting criminal conduct by some method or device that would not reveal any information concerning lawful items or activities. Could the acquisition of such information under these circumstances constitute an "unreasonable search" under the Fourth Amendment? This scenario is not merely hypothetical. The most prominent reality in which this question arises involves specially trained dogs, which, using their superior sense of smell, can alert to the presence of illegal drugs. Most dramatically, suppose that such a specially trained dog ("drug dog"), from a location outside a home, alerts to the presence of illegal drugs inside that home. Assuming that the physical location of the dog at the time of the sniff is not itself an intrusion into a valid privacy interest protected by the Fourth Amendment, the question is whether the sniff itself constitutes a "search" under the Fourth Amendment. In this Article, I suggest that the answer is no - i.e., that the sniff itself is not a "search" under the Fourth Amendment. I also suggest that the considerable opinions and authorities to the contrary are all premised upon a failure to begin the analysis with the Fourth Amendment itself.