Last month, the U.S. Supreme Court decided Florida v. Jardines, holding that police violated the Fourth Amendment by bringing a dog to a suspect’s front porch for several minutes to sniff for drugs, without a search warrant. Because the police subsequently obtained a warrant on the basis of the dog’s positive alert for narcotics, the Court deemed the marijuana plants that turned up during the subsequent search of the home to be the fruit of a Fourth Amendment violation that should therefore have been suppressed. The ruling itself might seem straightforward on its face, but a look at the majority and concurring opinions raises important questions about where we go from here in understanding the constitutional right to be free of unreasonable searches.
The Majority Opinion
In a 5-4 opinion for the Court, Justice Scalia explains the conclusion that police performed an “unreasonable search” in bringing a drug-sniffing dog to Joelis Jardines’s front porch to determine whether Jardines had narcotics inside his home. The opinion observes that the front porch onto which the police entered exemplifies the “curtilage,” the area “immediately surrounding and associated with the home.” A front porch therefore receives some of the core Fourth Amendment protection that attaches to the home itself. The Court concludes that it must therefore be vigilant about a potential constitutional infringement when law enforcement officers enter the front porch without a warrant.
Observing how the curtilage differs from the home, the Court acknowledges that home residents recognize a limited implied “license” for people to come onto their front porches, so that such entries are not tantamount to opening a person’s front door and walking in without an invitation. People delivering mail or packages, for example, may walk onto the person’s front porch and either knock or place the packages near the door, though they could not have simply entered the house and deposited the packages inside. Neighbors and even “solicitors, hawkers and peddlers of all kinds” enjoy a similar “implicit license” to “approach the home by the front path, knock promptly, wait briefly to be received, and then (absent invitation to linger longer) leave.”
If all of these types of people, including those offering goods that the resident likely does not want, enjoy an implicit license to walk onto the porch, then why is the police officer in Jardines any different? One might be tempted to think that it is because he was a police officer, and the limited license for mail carriers, neighbors, and salespersons does not extend to law enforcement. The majority opinion rejects this notion, however, specifically stating that “a police officer not armed with a warrant may approach a home and knock, precisely because that is ‘no more than any private citizen might do.’” The “license” to enter the porch therefore extends, sometimes, to law enforcement officials investigating criminal activity.
Under existing precedents, it is actually not surprising that police would be able to do the same things that civilians are authorized to do, though their objectives may differ, since this concept undergirds the “reasonable expectation of privacy” framework within which the Supreme Court has consistently operated since it decided Katz v. United States in 1967. The idea is that before a government action will qualify as a “search” and thereby trigger the protections of the Fourth Amendment (which may require a warrant or some other pre-search justification), it must invade a “reasonable expectation of privacy.” Such an expectation is one that individuals can legitimately expect to enjoy from private interference, in the absence of any governmental action.
If individuals have no reason to expect privacy against civilian surveillance of a particular sort—being looked at on the street, for example—then they similarly have no constitutionally protected basis for expecting privacy against the same kind of surveillance by law enforcement officials. Police must accordingly obtain a search warrant (in most circumstances) before entering a person’s home, but they need not obtain any warrant, or even have probable cause, before driving behind the same person on the highway.
The problem with applying this framework in Jardines, however, is that the majority opinion chooses not even to reach the question whether police violate any reasonable expectation of privacy when they bring a trained dog to a suspect’s front porch to sniff for narcotics. Explaining that it “need not decide whether the officers’ investigation of Jardines’ home violated his expectation of privacy under Katz[,]” the Court relies instead on the text of the Fourth Amendment to say that front porches are part of the “houses” enumerated in that text (“persons, houses, papers, and effects”) and thus may not be lawfully invaded by police without either a warrant or an implied license to walk up to the front porch (such as that enjoyed by mail deliverers and traveling salespeople).
The text of the Fourth Amendment, according to the majority opinion, so easily resolves the Fourth Amendment question that there is no need to resort to “reasonable expectations of privacy” analysis. As Justice Scalia’s opinion explains, “[o]ne virtue of the Fourth Amendment’s property-rights baseline is that it keeps easy cases easy. That the officers learned what they learned only by physically intruding on Jardines’ property to gather evidence is enough to establish that a search occurred.”
One might ask, however, why the Court believes that there is an implied license that covers police knocking on the door to talk to a suspect (sometimes called a “knock and talk”) but not an implied license that covers a “walk and sniff” by an officer and his dog. Perhaps, readers might speculate, the difference here lies in the fact that the police officer in the second case has a dog with him. That cannot be it, however, because neighbors often have dogs with them. Also, the Court expressly states that “[i]t is not the dog that is the problem, but the behavior that here involved use of the dog. We think a typical person would find it ‘a cause for great alarm’ … to find a stranger snooping about his front porch with or without a dog.” (emphasis in the original).
Fair enough. Neighbors’ sniffing around the door would be unusual and even alarming. But if the dog is not a central reason for the illegality of what the police did, then we can easily modify the facts in ways that raise questions about what exactly the Court is holding in Jardines.
Imagine that instead of spending two minutes in front of the door with the dog “energetically exploring the area” and “tracking back and forth, back and forth,” the police officer at issue had walked onto the front porch, accompanied by a narcotics-trained dog, knocked on the door, and then—while the officer waited a few seconds for the resident to answer the knock—the dog sniffed and indicated that there were narcotics inside. Would that represent a warrantless search? Under the majority’s analysis, it would seem that the answer is no, since, in the majority’s view, the problem is not the dog.
One difference between the officer in this hypothetical example and a neighbor with a dog is that the officer and the dog here are investigating criminal activity. The dog has specialized training. But so what? The police officer here also has specialized training (to make observations that civilians might be neither interested in, nor capable of, making). And the majority opinion does not rest on the dog’s special training but rather, it seems, on the dog’s particular behavior at Jardines’s house.
Therefore, the dog’s special training seems to qualify the activity as a Fourth Amendment “search” for only three of the nine Justices, as per the concurring opinion by Justice Kagan, which treats the trained dog as the equivalent of a high-tech device. In a case involving the hypothetical facts I discuss above, then, it may well be that no search warrant would be required. And even if the officer’s decision to knock on the door were merely pretextual, that would not matter, because under Whren v. United States, the Fourth Amendment judges only whether the objective conduct of the officer is legal, not whether the officer harbors some illicit motive for engaging in the outwardly lawful conduct, a proposition that the majority affirms in Jardines, stating that “a stop or search that is objectively reasonable is not vitiated by the fact that the officer’s real reason for making the stop or search has nothing to do with the validating reason.”
For the three concurring Justices, however, for whom the narcotics dog’s special training is dispositive (and would therefore govern the hypothetical case above), there lies a different problem. Justice Kagan writes that under a “reasonable expectations of privacy” analysis (rather than the straight textual analysis undertaken by the majority), residents can reasonably expect not to encounter a neighbor or other private party using a narcotics-detection device on their homes. In other words, the concurring Justices regard the narcotics-sniffing dog as no different from a piece of machinery built to detect marijuana or other controlled substances, machinery that is not in general use. Thus, the concurring opinion states: “The equipment they used was animal, not mineral. But . . . that is of no significance in determining whether a search occurred. [The detective’s] dog was not your neighbor’s pet, come to your porch on a leisurely stroll . . . . [but a] highly trained tool of law enforcement.”
The equivalence that the three concurring Justices draw between a dog and a drug-detection machine, suffers from a number of flaws that I explore in greater detail here. One important distinction is that unlike a high-tech device, a drug-detection dog is really just a regular dog who has been trained to communicate sensory knowledge that he probably had all along. In other words, most dogs have a sense of smell that is far superior to human olfactory capacities. To train a dog to detect narcotics, therefore, is in reality to train the dog to let his human handler know when he (already) detects narcotics.
To give a personal example, I used to have a German Shepherd Dog whom I named Mandy. Mandy was not a trained narcotics sniffing dog. However, she had a powerful sense of smell, which allowed her to let me and my spouse know facts that we otherwise would not have known.
When Mandy first joined our family, we already had an older dog named Scooter. Scooter often hid somewhere in the house, and we could not always locate him immediately. We therefore took to asking Mandy, “Mandy, where is Scooter?” Mandy would quickly get up and begin walking, slowly, sniffing the air, until she stopped, in front of a room or a closet and looked up at me or my spouse (whoever had made the inquiry). One of us would then open the door, and there would be Scooter, typically asleep. This game was fun for everyone.
Then one day, during a blizzard, I went out with Mandy and Scooter to play ball with them in the snow. Mandy lost interest in chasing the ball, and I had no idea where the ball was, buried as it had to have been in over three feet of powder. I said to Mandy, having played this game in finding Scooter, “Mandy, where is the ball?” Mandy promptly put her nose to the snow, began padding around from side to side, nose down, until she stopped at what looked like a random spot. She started digging furiously and then dipped her nose down and lifted her little green tennis ball. I was glad not to have lost her ball in the snow. Another time, when Scooter ran off during a snow-shoeing hike (yes, I like snow), I made the same request I often did in the house, and Mandy managed to find her adoptive brother as easily as she had found the ball, though he had wandered much further away than the ball had in the blizzard.
Mandy was not an animal-based instrument. She was a sentient living being who, like so many dogs (and wolves, for that matter) came into this world with a heightened capacity to detect and distinguish smells. I am not a skilled dog trainer (an assertion to which anyone who has met the dogs who live with me and my family could attest). But when we combined Mandy’s innate skills with the two-way communication that often develops between people (including civilians) and their animal companions, I could enlist her assistance in tracking down missing dogs and missing tennis balls. And this borrowing of Mandy’s skills was not different in kind from what police do with narcotics-detecting dogs.
Perhaps more important in its implications for the Fourth Amendment than the weakness of the concurring Justices’ analogy between dogs and hi-tech machinery is the Justices’ seeming indifference to the fact that narcotics dogs alert only to contraband, a matter in which the Court has said people lack any reasonable expectation of privacy. In other words, in cases like Jardines, the dog communicates to the police officer the answer to only one question: Is there any of a group of illicit drugs in this house? The dog does not provide a separate indication for whether there are people inside the house, though she can almost certainly detect that information as well.
By contrast, the thermal detection device in Kyllo v. United States revealed heat patterns that could expose not only the presence of unlawful materials (such as marijuana plants) but also intimate, lawful activity. In the Court’s words, “[t]he Agema Thermovision 210 might disclose, for example, at what hour each night the lady of the house takes her daily sauna and bath.”
As we know, of course, a dog may be mistaken in her belief about the presence of narcotics in the home. And, this mistake could, in turn, lead to a warrant and the search of an innocent person. But this fallibility problem plagues humans as well, and it bears on the gap between probable cause and certainty, not on the question whether a narcotics sniff and alert themselves invade any reasonable expectation of privacy.
The majority in Jardines rests its decision on the location of the police officer and the dog on private property, rather than on any reasonable expectation of privacy. Does the three-judge concurring opinion, however, which does rely on privacy, mean to say that people now do maintain a reasonable expectation of privacy in the fact that they possess contraband? After all, the concurring opinion alleges that “[i]f we had decided this case on privacy grounds, we would have realized that Kyllo v. United States, already resolved it.” That is only true if there is indeed a reasonable expectation of privacy in the simple fact that one’s home contains unlawful materials, particularly since, unlike in Jardines, the police in Kyllo stayed outside of the resident’s home and curtilage when they used their thermal detection device.
The concurring opinion responds to the dog sniff cases (finding no reasonable expectation of privacy in the possession of contraband) by distinguishing those precedents as involving vehicles: “[W]e have held, over and over again, that people’s expectations of privacy are much lower in their cars than in their homes.” But if even the possession of contraband in the home enjoys a reasonable expectation of privacy, then one might wonder why the majority in Kyllo bothered to say that thermal detection devices could potentially expose innocent, intimate facts. It could simply have said that these devices reveal information about the presence of narcotics in the home that would ordinarily have remained unknown in the absence of an entry, and that all such information—even when it is purely criminal information—enjoys a reasonable expectation of privacy in the home.
If the concurring Justices truly believe that every fact hidden in the home enjoys a reasonable expectation of privacy, then consider their view of the following hypothetical scenario: Armed gunmen abduct a three-year-old child from his home. The victim’s family contacts the police immediately after the abduction, and the police department dispatches several officers and trained bloodhounds to the victim’s home. The bloodhounds are given some items of clothing recently worn by the three-year-old to sniff, so that they know what scent to try to track down. The police then walk with the dogs, up and down the public sidewalks of the neighborhood, (without entering anyone’s front porches), in concentric circles, until the dogs all stop, facing John Doe’s house, and indicate that the boy’s scent is coming out of that house.
Would the concurring Justices say that the police “searched” Mr. Doe’s home without probable cause or a warrant? Would they say that the police also “searched” all of the other homes in the neighborhood, where the dogs did not alert? The dogs did nothing distinct to Mr. Doe’s home, after all—they just inhaled the scents that emerged from each house they passed and indicated, by continuing to walk along, that the home did not contain the child’s scent, or indicated, by stopping, that it did.
If this scenario feels different from the sniff of Mr. Jardines’s front porch, it may be because you believe that the state has a far stronger interest in finding an abducted child than it does in locating illegal narcotics. That may well be true. But the strength of the state’s interest generally helps us determine whether a search is reasonable, not whether there is a search—an invasion of a reasonable expectation of privacy—at all. Do the concurring Justices truly wish to maintain that walking a bloodhound on a sidewalk by various houses to find out whether an abducted child is present inside one of the houses invades neighborhood residents’ legitimate expectations of privacy? Stated differently, would any innocent person object to police learning whether an abducted child is inside their house, when police otherwise leave all privacy intact?
The majority opinion eschews reliance on the “reasonable expectation of privacy” framework and thereby (perhaps) escapes this problem. The police and the police dog entered Jardines’s curtilage and behaved in a manner that exceeded the implied license for entry onto the porch. Furthermore, although none of the Justices discusses this at all, having a police officer and narcotics dog on one’s front porch may stigmatize the inhabitant, in the eyes of his neighbors, as a drug-dealer, even if the dog communicates to the police that the residence is clean. Had the police been further from the house, as the officers in Kyllo were, then such a stigma might be avoidable. The matter of stigma, however, made its way into exactly none of the Justices’ opinions.
Unfortunately, Jardines leaves us with more questions unanswered than answered. A majority tells us that the problem was essentially an entry onto a private porch (which falls under the Fourth Amendment term “houses”) in a highly unusual and unexpected (and thus unauthorized) manner. But three of the five Justices in that majority strongly imply that there would have been a search (and thus a Fourth Amendment violation) even if the police officer and the dog had been off the premises, as the police in Kyllo had been, but had nonetheless gained information about the presence of contraband inside the house through a sniff. The dissenters feel no need to choose between the two definitions of “search,” but they find nothing objectionable in the sniff that took place. I accordingly predict that we may have a very different holding when police have humbly knocked on the door with a dog who detects narcotics immediately, a holding that would leave the three concurring Justices, Kagan, Sotomayor, and Ginsburg, as dissenters to a 6-3 opinion for the Court.