Paired for argument with another drug-sniffing dog case this week, Florida v. Jardines is half of the US Supreme Court's first review of canine narcotics detection since 2005. Arguably, it is the Court's first serious review of drug-sniffing dogs. The question in Jardines is whether bringing a drug-sniffing dog to the front door of a home constitutes a Fourth Amendment search. Companion case Florida v. Harris will examine the evidentiary value of drug-dog alerts.
Jardines could, and should, be much more than a thumbs-up or thumbs-down on drug-dog searches at the home, though. It is an opportunity for the Court to revamp Fourth Amendment doctrine, which was thrown open by January's decision in US v. Jones.
In Jones, the Court was unanimous about the unconstitutionality of GPS tracking absent a warrant, but it divided evenly as to Fourth Amendment rationale. Justice Antonin Scalia's majority holding used property rights rather than the "reasonable expectation of privacy" test preferred by the four-justice concurrence in the decision authored by Justice Samuel Alito.
Jardines would be a good case for closing the door further on the "reasonable expectation" doctrine first articulated in Katz v. US. The test may be easy to use in the context of the home, but rather than intoning about "privacy" and "expectations" as courts have been doing since Katz, the Supreme Court should administer the Fourth Amendment as a law. It should find that a search has occurred when the behavior of government agents is consistent with the meaning of the word "search." That is, when they seek information that is otherwise imperceptible to them.
Jardines does seem teed up to find that a dog-sniff is a search, given the proximity of this particular dog-sniff to the home. "Houses" are a sanctuary particularly listed as protected in the Fourth Amendment, of course, and courts have been rightly solicitous of the home since the beginning. However, if the Court is going to find that a dog-sniff is a search at the home, it must dislodge the doctrine that solidified in Illinois v. Caballes. In that case, the Court found that trotting a drug-sniffing dog around a car stopped for a different, legitimate reason is no search at all.
Citing US v. Jacobsen, Justice John Paul Stevens opined in Caballes that "[o]fficial conduct that does not 'compromise any legitimate interest in privacy' is not a search subject to the Fourth Amendment." Further, he asserted: "We have held that any interest in possessing contraband cannot be deemed 'legitimate,' and thus, governmental conduct that only reveals the possession of contraband 'compromises no legitimate privacy interest.'" Accordingly, the Court approved the examination of Caballes's car, which had been stopped for an ordinary traffic offense.
I labeled this rule the "Jacobsen/Caballes corollary" in a Cato Institute brief [PDF] to the Court in Jardines. It is a perfectly logical extension of the "reasonable expectation of privacy" rule that emerged from Justice Marshall Harlan's concurrence in Katz. However, the corollary demonstrates the illogic of the "reasonable expectation of privacy" test.
Recall what Harlan's solo concurrence in Katz said: "My understanding of the rule that has emerged from prior decisions is that there is a twofold requirement, first that a person have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as 'reasonable.'"
Since then, courts have almost never implemented the first part of the test. They generally assume objectively what a defendant must have thought, rather than finding as a fact his or her subjective state of mind. As to the second part, courts generally decide what society deems "reasonable" without much reference to any society beyond the membership of the Court itself.
This misapplied test permits logical extensions to illogical results: if searches are what disturb reasonable expectations of privacy, then an examination focused only on discovering illegal drugs cannot be a search (having banned them by law, society must believe it unreasonable to keep their existence private). Any examination tuned finely enough to find only illegality is not a search. This is the Jacobsen/Caballes corollary to Katz.
Applied in Jardines, the Jacobsen/Caballes corollary would dispense with the search question while allowing government agents to go door-to-door looking for drugs. If it is no search to enter property as a lawful visitor with a drug-sniffing dog, it would be no search to canvass entire neighborhoods, lines at movie theaters and concert halls with drug-sniffing dogs.
This logic need not apply only to canis lupus familiaris. The Department of Homeland Security (DHS) has various technologies under development that could fit within the Jacobsen/Caballes rule even though they are highly invasive.
One, called Future Attribute Screening Technology (FAST), would examine Americans' biologic cues — cardiovascular signals, pheromones, electrodermal activity, respiration, and so on — to detect intent to cause harm. Examination of this type would not invade a "reasonable expectation of privacy" because it would indicate only the existence of a criminally guilty mind.
Another DHS program is called the Remote Vapor Inspection System (RVIS). The RVIS generates laser beams at various frequencies to be aimed at a target vapor. The beams reflected and scattered back to a sensor reveal spectral signatures that can be matched to the signatures of sought-after gases and particulates. Using the RVIS, government agents might remotely examine the molecular content of the air in houses and cars, quietly and routinely explore the gasses exiting houses through chimneys and air ducts, and perhaps even silently inspect any person's exhaled breath. If RVIS technology is programmed to indicate only on substances produced by wrongdoing, the Jacobsen/Caballes corollary means that even pervasive, frequent and secret use would be considered no search.
Of course utilizing these technologies constitutes a search. Black's Law Dictionary defines "search" as "looking for or seeking out that which is otherwise concealed from view." A search (and sometimes a seizure, or both) is how something is made perceptible when it is not in plain view.
The question whether a search has occurred should turn first on whether something is concealed, the opposite of exposed. Black's Law Dictionary defines the verb "to expose" as "[t]o show publicly; to display; to offer to the public view, as, to 'expose' goods to sale, to 'expose' a tariff or schedule of rates, to 'expose' misconduct of public or quasi-public figures."
Exposure is a condition that can be determined objectively by reference to the physical locations and properties of things. When a letter is kept in a desk drawer inside a home, its location and the opacity of the desk and walls of the home prevent photons from bouncing off the letter and reaching the eyeballs of people not permitted inside. A cat in a yard along the street is exposed because photons it reflects will come to rest in the eyes of passers-by. Bedroom conversation inside a home generally cannot be heard on the side-walk. A shouting match on the front porch is exposed.
When government agents use some technical artifice to perceive information they otherwise cannot, that is a search. In Kyllo v. US, government agents used a thermal imager to "see" the unusually high temperatures of the walls of a home. A thermal imager converts invisible radiation in the infrared range of the electromagnetic spectrum (that is, with longer wavelengths than visible light) into imagery within the visible spectrum. They used this information to validate their suspicion of a marijuana grow operation.
For the majority in Kyllo, Scalia wrote: "Where, as here, the Government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a 'search' and is presumptively unreasonable without a warrant."
This is what occurs with drug-sniffing dogs. Though dogs are common, trained drug-sniffing dogs are not. And though cute, drug-sniffing dogs are chromatographs. They are devices for detecting particulates at levels well below that of human perception. They make perceptible to government agents what is otherwise imperceptible. Drug-sniffing dogs are used to search for drugs.
That simple rule — that it is a search to make perceptible something that was otherwise imperceptible — would dramatically improve the administration of the Fourth Amendment. When a search has occurred, courts could then apply their judgment to whether the search was reasonable.
Under current doctrine, courts look the wrong way in Fourth Amendment cases, through lenses they are not equipped to wear: they examine whether the privacy expectations of the citizen are reasonable. The question is whether government searches and seizures are reasonable. Bringing a drug-sniffing dog to the front door of a home is most definitely a search, and basing such a search on an uncorroborated tip is most likely unreasonable.