In 2005, the U.S. Supreme Court decided a case presenting this question: Does the Fourth Amendment require reasonable, articulable suspicion to justify using a drug-detection dog to sniff a vehicle during a legitimate traffic stop?
Roy Caballes was stopped for speeding by a state trooper in Illinois. During the stop, the trooper noticed an altas, an air freshener, and some suits in the car. He asked Caballes for permission to search the car and was denied. A second trooper arrived at the scene with a drug-sniffing dog. While walking around the car, the dog alerted the trooper to the presence of drugs. The first trooper searched the car and found marijuana in the trunk. Caballes was arrested, tried, and convicted of a narcotics offense. The Illinois Supreme Court reversed the trial court's decision, arguing that use of the dog "unjustifiably enlarge[ed] the scope of a routine traffic stop into a drug investigation." The state of Illinois appealed to the U.S. Supreme Court.
Part I of the excerpt below is from the majority opinion (decision) about the question presented in the case. Part II and III are from the opinions of Justices who dissented from (did not agree with) the majority's decision.
I.
Held: A dog sniff conducted during a concededly lawful traffic stop that reveals no information other than the location of a substance that no individual has any right to possess does not violate the Fourth Amendment.
...This conclusion is entirely consistent with our recent decision that the use of a thermal-imaging device to detect the growth of marijuana in a home constituted an unlawful search. Kyllo v. United States, 533 U. S. 27 (2001). Critical to that decision was the fact that the device was capable of detecting lawful activity—in that case, intimate details in a home, such as "at what hour each night the lady of the house takes her daily sauna and bath." Id., at 38. The legitimate expectation that information about perfectly lawful activity will remain private is categorically distinguishable from respondent's hopes or expectations concerning the nondetection of contraband in the trunk of his car.
From Illinois v. Caballes, Docket No. 03-923, Argued November 10, 2004-Decided January 24, 2005. Justice Stevens, delivered the opinion of the Court, in which O'Connor, Scalia, Kennedy, Thomas, and Breyer, JJ., joined.
II.
The Illinois Supreme Court, it seems to me, correctly apprehended the danger in allowing the police to search for contraband despite the absence of cause to suspect its presence. Today's [U.S. Supreme Court] decision, in contrast, clears the way for suspicionless, dog-accompanied drug sweeps of parked cars along sidewalks and in parking lots.
From Illinois v. Caballes (2005). Justice Ginsburg, with whom Justice Souter joined, dissenting.
III.
The dog sniff in this case, it bears emphasis, was for drug detection only. A dog sniff for explosives, involving security interests not presented here, would be an entirely different matter...
...This Court has distinguished between the general interest in crime control and more immediate threats to public safety.
From Illinois v. Caballes (2005). Justice Ginsburg, with whom Justice Souter joined, dissenting.
Focus Questions:
1. What differences if any, do you see between the example of the dog-sniff search described in the excerpt, as opposed to the search involving the thermal-imaging device, also described in the excerpt (see Part I)?
2. What do you think of the premise (see Part I above) that the parameters of an unreasonable search are partly defined by whether the search might detect lawful activity? Why do you hold that view?
3. To what extent do you agree with Justices Ginsburg and Souter that the Caballes decision clears the way for suspicionless dog-searches, and, how would you react if you were subjected to such a search?
4. Do you agree with the premise described by the dissenters that a lower constitutional threshold exists for searches when suspicions involve criminal matters(such as finding of illegal drugs) than for cases suspicions involving public safety and security issues (such as possession of explosives)? Why?