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The dog-sniffing cases: Made simple

Editor’s note: During the Supreme Court’s summer recess, the blog will be publishing a series of posts that explain, in non-legal terms, some of the most important cases that will be decided in the new Term that starts October 1.  This is another in that series.  This post explains two cases, Florida v. Jardines and Florida v. Harris.  Both involve the use by police of dogs that can detect the odor of illegal narcotics.  The Court has scheduled those cases for separate hearings on Wednesday, October 31.


Police forces across the country have found that dogs, which have a highly developed sense of smell, can be trained to detect specific odors, such as scents from a human body, or the odors given off by illegal drugs.  This makes police dogs highly valued partners to police as they search for missing persons, or for illegal narcotics.  When a trained dog’s capacity to detect a certain odor has been formally certified by an expert, the evidence that police gain from dog searches frequently is permitted in criminal cases in court.  But the Supreme Court several times has had to rule on whether a search by a trained police dog is the kind of inspection that must be done so that it does not violate the constitutional right to privacy of the individual targeted.   The Court  will give further constitutional guidance in two new cases, both originating in Florida.

The Fourth Amendment is one of the Constitution’s strongest guarantees of personal privacy, especially for the privacy of the home.   The Supreme Court has made clear that the protection given by the Amendment is intended to protect people, rather than physical space.  But its protection does extend beyond the individual’s own body, to places and things which the owner and society in general would recognize as intended to be free from government intrusion.   Thus, the protection can apply to houses, documents, and personal belongings.   Searches by police or other government agents, however, are generally barred only if they are “unreasonable.”   That is a sufficiently flexible word that courts have traditionally had to fill in meaning on how to apply it in specific situations.  The Amendment also provides that, as a general rule, police cannot carry out a search unless they have the permission of a judge, through a “warrant.”  Police can obtain a warrant to carry out a search only if they have a fairly strong reason to believe that the search will turn up evidence of crime.  Police do not have to be absolutely certain that the search will lead to evidence, but rather that prospect must be “probable.”  In some situations, a warrant is not needed, but police still need to show that a search “probably” will turn up criminal evidence.

But, before Fourth Amendment protection comes into play, police activity must actually be found to be a “search” in a legal sense.  For example, if one puts the family trash out on the curb, police can inspect it without getting a warrant because the family has given up any expectation that the contents of the trash bags are private.   But, if the trash is still in the can inside the house, perhaps in the kitchen, police could search it only if they got a warrant allowing them to do so; that would be a search in a place that the homeowner considers to be private, and so does society in general.   For another example, if one keeps drugs in the glove compartment of a car or truck, and police pull over that vehicle for a traffic violation, police are not allowed to search the glove compartment unless they have some reason to think that the search will turn up evidence related to the reason the vehicle was stopped.  But if the individual, on getting out of the vehicle, drops a package of drugs on the ground, police can gather that up and use it as evidence, because they were not searching for it when it just turned up.

It is clear, then, that the factual situation can make a difference constitutionally.   And that is why the Supreme Court has had to return periodically to define the situations in which the police may use a drug-sniffing dog, without violating someone’s right to privacy under the Fourth Amendment.   That issue arises, of course, because a well-trained drug-sniffing dog, by giving an “alert” to its police handler when the animal smells a specific drug, may actually lead the police to the discovery of evidence of a crime.  If the Fourth Amendment does not apply at all, police may hand over that evidence to a prosecutor who pursues criminal charges.  But if the Fourth Amendment might apply, the evidence might be valid or it might not be, depending upon the factual situation.

Police and prosecutors have generally argued in court cases that the use of a drug-sniffing dog is not a “search” at all, because the only thing that a dog’s “alert” identifies is something that is illegal anyway, and no one has any privacy right in illegal items or substances.  The Supreme Court has sometimes embraced that argument.

For example, the Court has ruled that it is not a “search” under the Fourth Amendment if police use a dog to sniff the exterior of luggage that police have temporarily seized in an airport terminal, believing that it is likely to contain something illegal.  It also has allowed police to check the outside of a vehicle that police have legitimately stopped at a highway checkpoint set up to search for illegal drugs, or to check the outside of a vehicle that police have legally stopped for a suspected traffic violation.   In each of those situations, the impact on privacy was considered to be very slight, because the intrusion was minimal, so the use of the dog did not violate the Fourth Amendment.

Suppose, though, that police use a dog to check for narcotics on the exterior of a home that they suspect is being used for drug trafficking.  Does the fact that the site of the search is a private home make a constitutional difference?  That is one of the new factual situations that the Supreme Court is now preparing to confront.  In the case of Florida v. Jardines, Florida’s state supreme court ruled that the U.S. Supreme Court’s past rulings on the use of drug-sniffing dogs did not apply at all when a dog was used at a home, even if the dog only sniffed exterior surfaces of a house.   Nowhere is the right of privacy stronger than in a private home, the state court said.

That case originated when police in Miami got a tip from a “crime stopper” source that the home of Joelis Jardines was being used to grow marijuana.  Police went to the home, based on that tip alone, and used a trained detection dog named Franky to check out the front porch of the house.  After circling for a few minutes, Franky sat down, near the front door.  That indicated to his police handler that the dog had detected an odor of marijuana coming from under the front door.  At that point, the officers obtained a search warrant, which the officers then carried out, finding a marijuana-growing operation inside the house.  Jardines was charged with growing illegal marijuana plants, but his lawyer contended that the search was unconstitutional because it intruded on the privacy of the home.

The state’s highest court relied primarily upon a 2001 Supreme Court decision, in the case of Kyllo v. United States, a ruling that it is unconstitutional for police to use a heat-sensing device aimed at the outside walls of a house, to check to see if marijuana was being grown inside with the use of high-intensity lamps.   When the government uses a device that the general public does not employ, and the police use it to explore the details of a home, the state court said, that is a “search” under the Fourth Amendment.   A trained dog’s sniff test fits into that category, it concluded, adding that such a test reveals not only the presence of something illegal, but it also is capable — when carried out in public view — of exposing the homeowner to public humiliation and embarrassment, and further is capable of being used in a discriminatory way.   Before police may conduct such a sniff test, it ruled, they must be able to show in court — after the fact — that they had more than mere suspicion that a crime was being committed in the crime; they had to have information indicating that it was “probable” that there was such criminal wrongdoing taking place in the home.   The bottom line of the ruling: the use of Franky at the Jardines home was “unreasonable,” so the marijuana evidence could not be used against him.

That ruling is being challenged by state officials of Florida in their appeal to the Supreme Court.   They have the support of the federal government for their challenge.   Their basic claim is that a sniff test by a drug is not a search at all, at a home or elsewhere.

In the other Florida case that the Justices will be reviewing (Florida v. Harris), state officials have persuaded the Court to return to the issue of a dog sniff test on a car or truck, not a home.  But this time, the sniff test was done on the inside of a private truck.   The Florida Supreme Court, finding that the U.S. Supreme Court’s prior rulings involving sniff tests and vehicles only involved checking the exterior of a vehicle, decided that the Fourth Amendment provided greater protection when the dog’s “alert” led police to search the interior of a vehicle.   But the decision also is important because the state court spelled out the information that police must have in order to convince a court that a drug-sniffing dog can be trusted to make a reliable “alert” indicating that illegal drugs were present.

A Liberty County sheriff’s deputy with a drug-detecting dog named Aldo, who had been trained to detect the illegal drug methamphetamine, was on patrol in Blountstown, Florida.   The deputy pulled over a truck driven by Clayton Harris because the license plate on the vehicle had expired.  The officer noticed that Harris was shaking badly, and was breathing rapidly — telltale signs, for the officer, that Harris might be on drugs.  The officer asked for permission to search the truck, but Harris refused.   The dog then “alerted” to a drug on the door handle of the driver’s side of the truck.  With that “alert” as legal justification, the officer searched the interior of the truck’s cab, and found ingredients for making methamphetamine.

Harris was charged with possessing materials for making the illegal drug, and his defense lawyer challenged the use of the evidence found in the truck’s cab, arguing that the search of the truck’s interior violated the Fourth Amendment because the deputy had no legal basis for conducting such a search.  The Florida Supreme Court agreed, concluding that Aldo’s “alert” to a substance on the truck door handle was not sufficient to justify searching the cab.  A police dog’s “alert,” the state court said, is not enough by itself to satisfy a court that the dog is properly trained and certified for the detection of a specific illegal drug.   A court can accept an “alert” as a basis for a search only if the evidence shows how the particular dog was trained, what was done to satisfy an expert that the dog was adequately trained, how the dog had actually performed in “alerting” to drugs in other situations, and how well trained and how experienced was the dog’s police handler.

The state court remarked that it appeared that, in dog-sniffing drug cases, “the courts often accept the mythic dog with an almost superstitious faith.  The myth so completely has dominated the judicial psyche in these cases that the courts either assume the reliability of the sniff or address the question cursorily; the dog is the clear and consistent winner.”

Finding in the Harris case that there was not enough proof that Aldo was a reliable drug detector, the state court overturned Clayton Harris’s no-contest plea to the criminal charge, because the evidence taken out of the truck cab should not have been allowed in court.

State officials, with the support of the federal government, have asked the Supreme Court to rule that the fact that a trained and certified dog does make an “alert” should be enough to justify a police officer’s further search of a vehicle for illegal drugs.




Recommended Citation: Lyle Denniston, The dog-sniffing cases: Made simple, SCOTUSblog (Jul. 26, 2012, 3:20 PM),