Late this past year the Supreme Court heard two cases related to the use of police dogs as drug detection equipment.  It has long been established (United States v. Place, 462 U.S. 696 (1983)) that dogs could be used to check luggage for drugs at customs checkpoints and airports, and more recently (Illinois v. Caballes, 543 U.S. 405 (2005)) that an alert by such a dog outside a car on a legitimate routine traffic stop provides a reasonable basis for searching the vehicle.  That was reaffirmed last month in Florida v. Harris; the more interesting case, Florida v. Jardines, challenges whether to expand this type of external searching to include homes.

The Fourth Amendment in the Bill of Rights protects Americans from "unreasonable searches and seizures", which means that the police cannot enter your home or office or other area in which you have a clear and reasonable expectation of privacy (it has included cardboard boxes in which homeless people live) and search for evidence of criminal activity absent some prior basis for believing that such evidence exists, sufficient to create "probable cause"--an articulable non-discriminatory basis for believing you might be involved in a crime which can persuade a judge to issue a warrant for deeper investigation.  One of the most notable exceptions to this rule is the "plain sight exception", that is, if the police knock on your door because the neighbors are complaining about the noise, or to alert you to a manhunt for a dangerous prison escapee, or to collect for the Policemen's Benevolent Association, and they see something illegal when you open the door; or if standing on the street they hear a discussion of criminal acts through an open window; or if they smell an illegal substance outside the home; they have a probable cause basis for obtaining a warrant to search, or in some cases (exigent circumstances in which the suspect might destroy evidence) to enter immediately.  There is an implied consent that any person, including a police officer, can knock on your front door, and thus can enter your property that far uninvited.

However, the Supreme Court is poised to decide whether this extends to his dog.

In oral arguments, the Court seemed unwilling to allow this.  An officer who comes to your door with a trained drug-sniffing police dog may be conducting an illegal search, because there is no implied consent to allow a drug-sniffing dog onto the property.  Thus a warrant based on the testimony that the dog reacted as if to the smell of drugs while on the suspect's property would be invalid; such detection methods exceed the "plain sight exception".

Although it applies specifically to dogs, it will also impact the use of technological surveillance.  We live in an age in which thermal imaging can identify the locations and shapes of persons and of medium-heat equipment inside buildings; where flying drones can pass over a roof and detect concentrations of chemicals in the atmosphere; in which airplane and satellite imaging can view into fenced or walled yards; where laser sound detection can pick up conversations off the vibrations of glass in your windows.  The ability to watch us, to put our most private rooms in the "plain sight" of investigating officers, has expanded beyond the science fiction imagination of placing cameras in our home televisions.  We can be watched.

Fortunately, there are limits on such methods.  That's not to say that they cannot be used; it says only that the police must already have probable cause.  Kyllo v. United States, 533 U.S. 27 (2001), has already held that thermal imaging (specifically in that case to search for evidence of the use of heat lamps to support marijuana growth) is a search and cannot be performed without a warrant; last year in United States v. Jones, 565 US ___, 132 S.Ct. 945 (2012) the installation of a Global Positioning System (GPS) device on a car to track its movement for a month was ruled a search, requiring a warrant.  The police cannot use more advanced technology to gather evidence about suspected criminal activity without first demonstrating that there is good reason to believe such evidence exists.

The present question, then, is whether they can bring a drug-sniffing dog onto your property without your consent unless they already have good articulable reason to believe that you are involved in drug crimes.  It will be a significant step for our protections against search and seizure in an age in which privacy is becoming more and more difficult to protect from technological snooping; the question is in which direction.

We introduced the subject of two cases pertaining to drug-detecting dogs while they were pending before the United States Supreme Court.  One of those, Florida v. Harris, 568 U.S. _____ (2013), was decided February 19th; the other, Florida v. Jardines, 569 U.S. _____ (2013) came out March 26th.  To the casual observer, they may seem contradictory; indeed, even the dissent in Jardines (a 5-4 decision) argues it is inconsistent with Harris (decided unanimously), so the distinctions might be significant.  Harris involved the use of a dog (Aldo) to sniff for contraband outside a vehicle at a lawful traffic stop.  Jardines involved a similar olfactory investigation (by Franky) on the front porch of a private home.

In Jardines, Justice Scalia delivered the opinion of the court, arguing based on trespass law that the implied consent for anyone to approach the front door of a home does not extend to drug-sniffing dogs.  Since the yard, or curtilage, is part of the private area of the home, entering it to obtain evidence constitutes a search under the Fourth Amendment.  They distinguish knocking on the door to question residents as an ordinary activity any neighbor or stranger might perform, and thus bringing the trained canine makes this difference.

The concurring opinion of Justice Kagan (who wrote Harris) would go further, saying that bringing the dog is an invasion of privacy, much as standing on the porch peering through windows with binoculars.  The dog is also compared to the thermal imaging rejected in Kyllo v. United States, 533 U.S. 27 (2001), as the use of advancing technology impinging on traditional privacy expectations.

The dissent, delivered by Justice Alito, rejects these arguments.  Dogs are ubiquitous in human society, and no one would argue that it is trespass to bring a leashed dog along the paved path to the front door.  Similarly, their olfactory abilities have long been used by police--fourteenth century Scottish laws against interfering with a bloodhound tracking a criminal demonstrate this.

It thus appears that the issue is, what are we to make of trained drug-sniffing dogs?  Are they more like chromatographic gas analyzers, or more like professional perfumers?  To date the court has generally treated them as the former:  a reliable technological breakthrough capable of detecting hidden substances such as drugs or explosives; yet even in unanimously affirming reliance on such a dog in Harris the court weakened that assumption.  The implications of these two cases present several issues; we are not done with this discussion.

Now we consider the implications of Florida v. Harris, 568 U. S. _____ (2013).

In short, on a routine traffic stop canine Aldo alerted to the odor of drugs at the driver's door of Harris' truck; a search found not drugs for which Aldo was trained but materials to manufacture such drugs.  Harris was charged, and while on bail he was again stopped, again Aldo indicated the door, but this time nothing was found.  Harris attempted to suppress the evidence of the first search, claiming that Aldo was unreliable as a basis for probable cause to search, having twice alerted in the absence of drugs.  At trial, Aldo's handler testified as to Aldo's and his own training and ongoing practice.  Defense argued that field performance was unproven, and the Florida Supreme Court agreed, asserting that detailed field records should be kept on such dogs to prove their reliablility.  The United States Supreme Court reversed:  barring specific evidence to the contrary, the training of such a dog makes him a reasonably reliable informant for probable cause to pursue a search.  The "false positives" at Harris' truck were not probative, as Harris admitted manufacturing methamphetamine, and dogs can smell trace presences and residual odors.

It seems on its face that the court allows that evidence could be introduced to argue that the dog's alert was unreliable.  General evidence--that such dogs frequently alert when handlers (incorrectly) believe drugs are present, or that drugs are found in only 20% of such searches--is insufficient; it must be shown that this dog is unreliable.

That suggests that wealthy defendants would have an advantage, in that discovery motions could insist the dog, and handler, undergo independent testing.  Yet even if the dog were demonstrably incompetent, it might not matter, as long as the handler is ignorant of the incompetence and has a reasonable basis to believe the dog's response sound.  Thus such tests might remove a dog from service or return him to training, but are unlikely to impact whether the handler reasonably believed the alert to be reliable at the time.  It would have to be demonstrated that the handler was unreasonably oblivious to or willfully ignorant of the animal's flaws.  That being unlikely, this case does not significantly impact such cases in a practical way:  a dog trained to detect such odors is effectively a reliable indicator of their presence as long as the handler did not know otherwise at the time of the search.

Which takes us back to Jardines.

Despite reservations expressed in Florida v. Harris, 568 U. S. _____ (2013), it appears that drug-sniffing dogs continue to be regarded as if a modern technological device, completely reliable in effect.  That appears to be the basis for the decision in Florida v. Jardines, 569 U. S. _____ (2013), and as such it has implications for the future use of technological surveillance in law enforcement.

In Jardines, the High Court found that the police were trespassing when they brought a detection-trained dog onto the defendant's front porch.  It is conceded that anyone, including the police, can approach a front door following a marked pathway to it for a variety of purposes, including talking to residents and leaving flyers, mail, or packages.  It is also conceded that bringing an ordinary dog to the door is perfectly acceptible, and that if a police officer present on a legitimate visit observes (by any natural sense) anything illegal or suspicious, that evidence is legitimately obtained and does not constitute fruit of an illegal search.  The problem with the dog is that its inhumanly superior natural olfactory sense has been trained by modern methods to recognize faint odors emitted by specific illegal drugs or explosives.

The dissent objects that canine oflaction has been used by law enforcement for centuries, in the form of bloodhounds tracking criminals.  Arguably such dogs were manufactured--bred by human intervention--for tracking, but for tracking animal prey; their use for tracking humans is secondary despite being established in centuries of law and enforcement.  The nearest use comparable to drug and explosives detection is probably trufflehunting.  Training dogs to identify odors that are not essentially biological is an entirely new concept.  It is that "newness" which seems to have caused the Court to categorize such dogs as a technological device.

This thus impacts the use of other technological devices.  The police may knock on your door, or stand on your porch, but just as they cannot use a thermal imager, they cannot bring a gas chromatograph, or magnetometer, or radar or ultrasound imager or parabolic microphone, nor any other device which enables them to detect anything an ordinary person could not detect in the same position without such a device.  Such devices, like trained drug-sniffing dogs, are not commonly carried by front door visitors, and so residential area residents reasonably expect not to have people bringing them on their property.

That, though, raises another issue, concerning "newness".

Precisely because drug-sniffing dogs are presumptively reliable it is an illegal search to bring one on private property without a warrant.  The court essentially ruled that because such techniques were new, their presence is unanticipated and thus not covered by the implied consent extended to visit private property.

That raises the issue:  what happens when they are no longer "new", and how will we know when that happens?  Some of the technologically sophisticated are already using wearable computers with mobile uplinks and facial recognition software.  If (as is not at all unlikely) infrared imaging becomes part of this expanding new technology, at what point does Kyllo v. United States, 533 U. S. 27 (2001), fall because such information is not only freely available but widely observed by ordinary citizens?  Directional audio amplification is already sold commercially for those with slight hearing impairment.  The techology exists for portable atmospheric analysis, infra- and ultra-sound detection; radar is being added to high-end cars for crash prevention.

Further, not only is technology advancing faster than ever before, the proliferation of technology is also accelerating:  the time it took for smart phones, e-readers, and tablets to become commonplace is a fraction of the time it took for personal computers and wireless phones to do so, and these in turn spread remarkably quickly as compared with, say, the telephone and automobile.  Even thirty years ago few imagined what is now commonplace technology.  Defining what is excluded based on what is uncommon and therefore unexpected is a standard that won't long stand.  Technological survellance equipment, and drug-sniffing dogs, will eventually become the norm, and then the exclusion will fall, and with it some of the privacy the court has defended and debated.

The only question then will be, what then will define the limits?

A reader called our attention to a New Jersey Supreme Court case, State v. Rashad Walker a/k/a Derrick Moss, which is curious as a search and seizure decision.

A tip led police to Walker's apartment, where they had been told a black man was dealing drugs.  They were preparing to elicit a purchase as proof, and Walker, a black male, answered the door smoking a hand rolled cigarette, and one of the officers immediately recognized the smell of marijuana.  He identified himself as police, Walker tossed the cigarette into the apartment and attempted to slam the door; one of the officers prevented the door from closing, and pursued, recovering the cigarette, arresting Walker, and once inside the apartment observing and confiscating other drugs which were in plain sight.  The New Jersey Supreme Court ruled this month that the search was valid, reversing the appellate court decision which had excluded the evidence taken in the apartment.  Our correspondent's question:  it seems obvious that the officers did everything right, so how did the appellate court reach a different decision?

The answer is primarily found in State v. Hutchins, 116 N.J. 457 (1989), along with the holdings in the U.S. Supreme Court case Welsh v. Wisconsin, 466 U.S. 740, 104 S. Ct. 2091, 80 L. Ed. 2d 732 (1984) and a few other cases.  It turns on whether the police were justified in entering Walker's home to arrest him for a minor offense (possession of a small quantity of marijuana), and in both of those cases they were not.  Hutchins is the more important; Welsh matters as the basis for Hutchins.

Welsh was a U. S. Supreme Court decision in which Wisconsin police in response to a tip that a man was driving erratically entered his bedroom and arrested him for drunk driving.  The court ruled that prior to reaching his bedroom the police had probable cause only sufficient for a reckless driving charge, a minor offense under Wisconsin law, and that entering someone's home to arrest him for a minor offense without a warrant was a violation of the protections intended by the Fourth Amendment.  That evidence might be lost (the suspect's intoxication) was insufficient.

In Hutchins, New Jersey police were acting on a tip very similar to the one in Walker, that a black man was selling drugs from an apartment.  A black man answered the door, and police stated that one hand was clenched in a manner that might be hiding an illegal substance.  When he saw that these were police, he attempted to close the door, and the police forced their way inside, saw illegal substances in the apartment, and arrested him.  The search of the apartment was deemed illegal because the tip was insufficient for probable cause to search or arrest, and the fact that a man has his hand clenched around something (which might as easily have been money to pay the pizza delivery boy) is not evidence of a crime.  Although Hutchins might well at this point destroy evidence, that is an exigency created by the police, which invalidates it.

In Walker, police saw the hand-rolled cigarette and smelled marijuana, so had probable cause to arrest for the very minor offense of possession of a small quantity, but not for searching the apartment.  The appeals court thought that when Walker retreated into his apartment and attempted to close the door, the police could not enter the apartment to arrest him for a minor offense (Welsh) and therefore could not follow him for an exigency they created (Hutchins).

Obviously the New Jersey Supreme Court disagreed.  What distinguished this situation is first that Walker was observed committing a crime, albeit a minor one, by smoking what was identifiable as marijuana, and that he attempted to throw the evidence into the apartment and flee immediate arrest into that apartment.  Police were justified both in pursuing a fleeing criminal and in following the path of the discarded evidence of the minor crime that might be destroyed if not recovered.  Once they were inside the apartment legitimately, the rest was valid.

Walker's mistake was trying to escape into his home with the evidence immediately after police had witnessed the crime and knew that he knew this.  He gave them the right to recover the evidence he threw into the home and, being informed that he was under arrest and fleeing custody, to follow him.  Those details make it different from Hutchins and Welsh, allowing the police to enter into evidence what they discovered after entering the home in pursuit of the suspect.

After all the above was published, the United States Supreme Court issued a per curium (unanimous statement by the court) on a significant case in this area, Torrey Dale Grady v. North Carolina, 575 U. S. ____ (2015).  The issue is whether a mandatory Global Positioning System (GPS) tracker attached to a person constitutes a search under the Fourth Amendment, and the answer given by the court, in short, is that it does.  This, though, is not the end of the story.

The beginning of the story concerns T. D. Grady, a registered sex offender convicted of two separate offenses, earning him the status of "recidivist".  The State of North Carolina has a statute on the books (N. C. Gen. Stat. Ann. §§14–208.40(a)(1), 14–208.40B (2013)) subjecting recidivist sex offenders to the possibility that they might be required to wear a GPS tracking device for the remainder of their lives.  Grady argued that the requirement was an unreasonable search under the fourth amendment, citing United States v. Jones, 565 U. S. ___ (2012), 132 S.Ct. 945 (2012) (which we discussed in connection with our look at Florida v. Jardines, 569 U. S. ___ (2013) concerning the use of dogs), which established that surreptitiously attaching a GPS device to a suspect's vehicle for the purpose of obtaining information about the suspect's movements constituted a search.  The North Carolina court rejected the argument and was upheld on appeal by the state's Court of Appeals on the basis that it was not a "search" because there was no evidence that it was being used to "obtain information".

The Court said, not in quite these words, that that was ridiculous, that the very name of the program "Satellite-based Monitoring (SBM)" suggested that it was about gathering information, and its text made it abundantly clear that it was to obtain "Time-correlated and continuous tracking of the geographic location of the subject" and "Reporting of subject’s violations of prescriptive and proscriptive schedule or location requirements"--obviously obtaining information.  The Court thus unanimously stated that this was indeed a "search" within the meaning of the Constitution, and so vacated the decision.

That is not the end of the story either, though.  The Court said that the issue never addressed in the lower courts, the one that mattered, is whether the requirement that the recidivist wear such a device was a "reasonable" search.  It is thus likely to return to the Supreme Court again, as whichever way the lower courts rule one side or the other will want the highest court to call it a mistake.

It is an issue worth deeper consideration:  if someone has been convicted of and sentenced for a crime, and serves the sentence, can he then be required to wear a tracking device for the rest of his life?  This is not the scenario in White Collar, in which the criminal is on parole and so technically still a prisoner.  It might arguably be different if the original sentence for the crime stated that the convict would be required to serve the rest of his life, a specific period of time incarcerated and the remainder on parole possibly wearing a tracking device, but technically once a criminal has served his sentence he is supposed to be released.  This becomes a second punishment for the first crime.  On the other hand, the state does have an interest in monitoring the movements of known repeat sexual predators even after they have served their sentences, and if the original sentence stated or implied (by the known existence of this statute) that such ongoing monitoring was an option upon completion of the mandated incarceration, it might be valid.

It is not an issue that touches most of us at this point.  It does not address whether the government is permitted to monitor data from GPS devices we voluntarily carry with us (such as our cellular phones).  At this point all it says is that requiring someone to wear a GPS device for the purpose of monitoring his movements is indeed a search, and that the courts must determine whether it is a reasonable search.