United States v. Place, 462
U.S. 696 (1983) was a decision by the
Supreme Court of the United States, which held that a sniff by a
police dog specially trained to detect the presence of narcotics is not a "search" under the meaning of the
Fourth Amendment to the United States Constitution. The Court reasoned that the sniff of a dog is
sui generis, intended to reveal only the presence or absence of narcotics. Because a dog sniff is so limited a test, the Court carved out this exception from the broad category of "searches" for which a warrant is generally required.
...
A "search" is an unwarranted intrusion on a person's objectively reasonable expectation of privacy. But the sniff does not require opening the luggage; it does not expose things that are not contraband to public view. The sniff is thus far more limited than the typical search. Moreover, the sniff merely reveals the presence or absence of narcotics. Thus, it is
sui generis, and does not constitute a "search" under the Fourth Amendment.