Florida v. Jardines: How is the Supreme Court going to clean up its drug sniffing dog mess?

Briefs and amicus briefs are being filed in a Supreme Court case that could have a major impact on Fourth Amendment jurisprudence in order to resolve a major mess. The question in Florida v. Jardines is whether a police officer can use a drug sniffing dog at someone’s door to determine if there is contraband inside the home. The mess is a result of the tension between the Supreme Court’s holdings, the reality of using drug sniffing dogs, and our intuitions about privacy.

First, the Supreme Court has held that, when performed in a minimally invasive way, like at an airport or outside one’s car, the use of a drug detection dog is not considered a “search” that implicates the Fourth Amendment or requires any suspicion. This is largely due to the fact that the use of drug sniffing dogs is considered a “binary search,” which either detects or fails to detect the presence of contraband. Because the Court has held in no uncertain terms that we have no legitimate expectation of privacy in contraband (I’m not as certain about this proposition when considering the history and purpose of the Fourth Amendment), a device or dog that detects only whether contraband is present or absent does not invade any expectations of privacy.

However, as Professor Leslie Shoebotham’s amici curiae brief (detailed on EvidenceProf blog) argues, drug sniffing dogs often detect the presence of  molecular compounds found in both contraband and innocent items, such as vinegar or soap.  Another way of framing this is that drug sniffing dogs are not binary because of their tendency to false positive. And there we have Mess Number 1: the Supreme Court’s drug sniffing dog jurisprudence is based on the false idea that the use of a drug sniffing dog is not a search because it detects only the presence or absence of contraband. It is unlikely that the Supreme Court in Jardines will reverse its firmly established position that the use of drug sniffing dogs is not a search. Instead, the Court will likely rely on the holding that a dog binarily alerts or does not alert to the presence of contraband, but will treat as a separate question whether a dog is accurate enough in its alert to give the police probable cause to obtain a warrant and conduct a full search of the home.

Thus, Mess Number 1 is more easily resolved than Mess Number 2, which concerns our intuition. It FEELS wrong for the police to march up to random homes and sniff doors with a drug detection dog. Yet, if the use of a drug detection dog does not actually infringe upon privacy rights or require any suspicion, that’s exactly what could happen. How is the Supreme Court going to distinguish a car or a suitcase from a house if the use of a dog is not a search at all?

Professor Orin Kerr, at The Volokh Conspiracy, proposes an interesting possible solution. Without evaluating likely outcomes or merits, he believes that the Court could hold that the home is a private area that cannot be invaded by drug sniffing dogs. Even if the dogs themselves are not intrusive generally, the door of a home cannot be sniffed because of its sanctity. The problem with this solution is that courts uniformly hold that we impliedly consent to allow individuals, police officers, mailmen, etc. to knock on our doors with no trespass to our privacy rights. Police can walk up to and knock on our doors without implicating the Fourth Amendment. So, according to Professor Kerr, this implied consent would have to be construed on a specific level of generality, such that the homeowner consents to visits by the police (and mailmen), but not sniffs by drug sniffing dogs.

I’m not convinced that this creative solution would clean up the drug sniffing dog mess; in fact, it might wreak more havoc on the jurisprudence. Much of Fourth Amendment jurisprudence hinges on the fact that once you expose something to the public, you lose all expectations of privacy and Fourth Amendment protection. If you admit to committing a crime to a friend, and that friend is wearing a wire, there is no expectation of privacy in that conservation. Of course, you did not consent for the police to become aware of that conversation, it was intended only for your friend, but the jurisprudence does not usually parse out to whom you intended to expose a private item. Similarly, if you place garbage on your street for the trash collector, you have forfeited an expectation of privacy against the police rifling through that garbage. It is unclear, based on the jurisprudence, why an individual could forfeit privacy in his front door with respect to the police, but not with respect to their canine friends.

A concurrence by Justice Sotomayor in United States v. Jones has questioned this logic, however.  I’d like to see the Court truly grapple with whether you can voluntarily expose information (or property) to some third parties without forfeiting your expectations of privacy with respect to others.

Although I am not usually one to propose pragmatic instead of principled doctrinal solutions, my forthcoming paper on quantifying probable cause argues that, if you force police to measure field accuracy rates of drug sniffing dogs, they will be less likely to use these dogs randomly on largely innocent populations.  Thus, the concern about drug dogs roaming through neighborhoods may be overstated in practice, although still theoretically alarming.  I will post a link to this article in a couple of weeks.


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10 Responses

  1. Orin Kerr says:


    I think there are two concepts here: First, whether and when a person has Fourth Amendment privacy rights; and second, if the answer to the first question is yes, whether and when a person consents to give up those privacy rights. The two questions behave somewhat differently: the former acts as an on/off switch, while the latter is more nuanced because its scope is tailored to the scope of consent.

    The cases you mention on false friends and trash are cases on when a person has privacy rights. The caselaw treats them in that first box of on/off switch cases. In contrast, the caselaw in the lower courts on approaching the home have concluded that you have a right but that you impliedly consent to an entry by the mailman, etc. That is, they have slotted these facts under the second rubric, not the first. That’s why I don’t think there is a mess here: The second rubric allows the tailoring to the scope of consent even though the cases from the first category do not.

  2. Erica Goldberg says:

    Orin Kerr,

    Thanks for your comment.

    Looking at the SG’s brief that you mention in your blog post, many of the knock and talk cases do involve whether there is a reasonable expectation of privacy on one’s doorstep. For instance, Reed asserts that, “courts have recognized no Fourth Amendment search occurs when police officers who enter private property restrict their movements to those areas generally made accessible to visitors — such as driveways, walkways, or similar passageways.” And, of course, KY v. King allows the knock and announce because private citizens may knock.

    Even in United States v. Lakoskey, the driveway portion involved the first prong of the analysis (reasonable expectation of privacy), and the implied consent referred to consent to actually enter the house. I can see why. Although your 2 pronged analysis would thread the needle, and might not require great upheaval in the doctrine, Fourth Amendment rights would then turn on the somewhat thin distinction (and somewhat legal fiction) between allowing a police officer to come by, but not bring his dog. People might consent to allow a police officer to come by if they simply want to chat, but probably not if a police officer is investigating a person.

    So, the Court could hold that there is no reasonable expectation of privacy in the doorway (because it is open to all visitors), and even at the door, and, on top of all that, using a dog is not a search anyway. However, I believe that this contradicts our intuitions about the creepiness of random drug sniffs at doorways. Or, the Court could hold that there is a REP in the doorway, although the knock and announce cases seem to indicate otherwise, but that our scope of implied consent is limited to police officers investigating the homeowner but not his dog. This would be a tough line to walk without being disingenuous, especially if we are accepting that using a police dog is not intrusive because it is binary.

  3. nidefatt says:

    You should have returned to your first puzzle. The reality is that drug dogs are a myth. Most police departments mistrain and misuse them. The use of a dog to gain entry to a home essentially allows an officer to use a false positive to enter a home that occurs far more often than it does with the electronic gadgets that Scalia already denied the police use of.
    What the Supreme Court should do, if it has any integrity at all, is revisit the reality of the use of drug dogs. Knowing, as we criminal trial lawyers do, the complexity of the puzzle, should make the Court be EXTREMELY unwilling to extend any sort of sanction to the use of dogs on homes. Totality of the tool approach- dogs may be fun at the airport, but we’re not bringing this mess into our homes.

    But then, if they had any integrity, they never would have gutted the knock and announce rule. Lord knows Roberts has no love for justice. I highly doubt anything good will come of Jardines.

  4. Ken Rhodes says:

    I would most strongly resist the bogus notion that the accuracy of the dogs’ positive responses is somewhow related to the issue. Do this thought experiment:

    (1) Make a doglike robot. Embed within it a hypothetical drug detector that is 100.0% perfect at detecting the presence of certain contraband drugs within a certain distance. No false positives, no false negatives.

    (2) Have a policeman bring his robot to your front porch, and have him use his robot to detect whether you have contraband drugs within your house. Is this a “search?”

    (3) Now put a pseudo flesh-and-fur casing on the robot to make it look and feel like a dog. Nothing is changed in the hypothetical. Is this a “search?”

    (4) Now breed a “real” dog that has the same 100.0% accuracy. Is this different because the dog is a living dog instead of a robot dog? I don’t see how that is relevant.

    The issue, IMO, has NOTHING to do with the accuracy of the dog’s detection. The dog is serving merely as an “instrument” for the police officer, just like an x-ray detector could dixcover the presence of a weapon concealed on a suspect.

    The issue is in the statement in the second paragraph:

    “Because the Court has held in no uncertain terms that we have no legitimate expectation of privacy in contraband…”

    What the heck is that??? The expectation isn’t in the contraband, it’s in the home. We have a reasonable expectation of privacy in our home, which is supposed to be secure against searches without warrants. If the cops use an x-ray machine to look into my home through the drawn drapes (or through the wooden door), unless they have a search warrant they’ve conducted an illegal search, haven’t they? How can it make sense that what they were searching for, if found, then retroactively disables my privacy and retroactively authorizes the search?

  5. Erica Goldberg says:

    Ken Rhodes,

    I hear you. But, if you look at a case like Kyllo, which held unconstitutional the use of an off the wall thermal imager, part of what was motivating the Court was the idea that intimate details within the home, like “at what hour each night the lady of the house takes her sauna,” might be revealed. I wonder how Kyllo would have been decided if the thermal imaging device somehow measured not heat, but simply whether there was marijuana in the home.

    If the dog/robot entered the home without a warrant, clearly we have a Fourth Amendment violation. An X ray machine that imaged the inside of a home or revealed details about the inside of the home would be similarly impermissible, via Kyllo. Here, the dog remains outside the house, and (potentially, with an accurate dog) exposes only criminal activity and nothing else about the inside of the home. I even think this case is distinct from the beeper cases, because no information about comings and goings within the home are revealed.

    I’m not advancing a position on how the Court should decide this case, but I do think it’s quite complex.

  6. Ken Rhodes says:

    Erica, in your sentence with the word “simply,” you make a leap from the assumption of privacy in my home to the alternative that the inside of my home is not private, if “all they can tell” is whether I’m hiding something I’m not supposed to have. Consider this hypothetical:

    The engineering geniuses at CalTech have developed a powerful x-ray device that can not only detect a gun through the wood front door of my house, but it is so precise that it can identify the make and model of the gun and even read the serial number. In fact, it’s so remarkably capable that it can even read and record the rifling in the barrel, so that the gun can be compared to the striations on bullets that were used to murder a victim. (This is only a hypothetical, of course, but don’t sell those CalTech guys short.)

    The police are working on a murder where they have the bullets, and they have a witness who says that I have stolen a handgun of the relevant make and model from him. Also, because the stolen gun had previously been fired at a firing range, and the owner has turned over the bullets for comparison, they know beyond a reasonable doubt that it was the murder weapon.

    Further, I have a known vendetta against the victim. These facts probably justify a search warrant for that particular gun in my house, although the search will probably be limited to the gun in question, and not to a general search for other incriminating evidence.

    Now take away the witness who says I stole his gun. Also take away any evidence of a “vendetta.” All they have is knowledge that at some recent time I disliked the victim. They can’t get a search warrant based on “hey, he didn’t like the victim, so let’s look in his house for evidence.”

    Can they nevertheless use the CalTech SuperXray to stand outside my house and look for the weapon inside my house? Without reasonable grounds for a search warrant?

    I think the Constitution is supposed to protect me from that search, and if paragraph two in the original post is accurate, then I think that sentence about “no expectation of privacy in contraband” is outrageous.

  7. Jim Maloney says:

    Ken, your hypothetical is thought-provoking, but I think it leaves quite a lot of room for the argument distinguishing “contraband” (always illegal to possess) from other items in the home that may or may not be illegal or incriminating depending on extrinsic information or circumstances (i.e., the gun in your hypo). High-tech gathering of info about in-home activities/possessions (via garbage searches) was, of course, upheld in 1988 in California v. Greenwood, but that was on the basis that there was no privacy interest in the garbage that was thrown out. In your hypo, the very fact that extrinsic circumstances have determined the specific object being sought make it more a “search” than would be the (theoretically) simple and infallible binary question of whether or not there is odorous contraband in the home. But, on another note, I think the line of cases that led to the flawed infallible-dog postulate needs to be reversed in much the same way that Plessy was reversed by Brown. “Separate but equal” and “dogs that never give a false-positive” are both mythical creatures.

    BTW, rumor has it that those CalTech engineers are working on a device that remotely detects fields of energy peculiar to spinning nunchaku, that Okinawan karate weapon that is so popular but wholly illegal to possess even in one’s home in both California and New York. No false positives. A crackdown on martial artists is imminent…

  8. Veracitor says:

    The fastest, and I suggest, best way to resolve this case is to apply the rule in Kyllo. Under the analysis in that case, use of a drug-sniffing dog* constitutes “obtaining by sense-enhancing technology [any] information regarding the interior of the home that could not otherwise have been obtained without physical “intrusion into a constitutionally protected area”…” and therefore “…constitutes a search.” Searches of homes (absent exigent circumstances) require warrants. Done.

    One advantage of this approach would be to supersede the need for inquiries into the accuracy of dogs or other instruments. Any instrument is (a) more able to see/smell/whatever through walls than a human, (b) less-able, or (c) equally-able. In situation (a) the instrument is probably forbidden by Kyllo (there is that pesky “in common use” question). In situations (b) and (c) the instrument is superfluous– it cannot do more than confirm the senses of the operator, which a second human could do as well. Since all the cases agree that humans may testify to evidence of their senses (e.g., that a witness smelt g*nja smoke) and such evidence may provide probable cause for a search, situations (b) and (c) are of little further interest.

    A decision along the lines I suggest would protect us from Ken’s robot dogs as well as real ones.

    *I realize that dogs are not accurate– in fact the Clever Hans effect turns them into dowsing rods which transmute the suspicions of their handlers into “indications”– but like Ken Rhodes I think this case doesn’t really turn on dogs’ accuracy.

  9. Jim Maloney says:

    But are dogs “sense-enhancing technology”?

  10. Joe says:

    “we impliedly consent to allow individuals, police officers, mailmen, etc. to knock on our doors with no trespass to our privacy rights”

    Going back to Kyllo, which highlights the privacy of the home, this “implied consent” rule (such rules generally have a certain artificial feel to them, basically tied to what society is deemed to “reasonably” refuse consent) should not be applied too broadly. This might raise line drawing issues, but that is fairly standard in the 4A context.

    We “consent” to certain public officials (or private parties really, unless there is a “no solicitation” sign) knocking on our doors for limited purposes. This includes the police knocking on our doors to serve warrants or to ask questions during investigations. But, do we “consent” to them bringing drug sniffing dogs that ala Kyllo have the potential to obtain private information or in general intrude (“invade” would be conclusionary) the privacy of the interior of the home?