Do Home Inspections by Drug-Sniffing Dogs Require a Search Warrant?

I’ve said before that the Supreme Court’s upcoming term may prove to be the most important one in decades – the court will be resolving an unusually-high number of extremely important cases. The Court has just added another interesting (though, admittedly, not earth-shattering) case to its docket. The case is called Florida v. Jardines, and the issue is simple: can police use a drug-sniffing dog at the front door of a private residence, to smell the interior of the residence looking for illegal drugs, without first obtaining a search warrant?

It’s actually quite surprising that this issue is just now being resolved. After all, way back in 2001, the Supreme Court decided Kyllo v. United States, holding that using an infrared camera to look into a suspect’s house from the outside constitutes a “search” under the 4^th Amendment, and therefore requires a warrant. And police dogs have been around a lot longer than infrared cameras. One would think that this issue would have been resolved decades ago. But, it hasn’t, and soon it will be.

This is an interesting case, and, like many that have come before it, it hinges on whether or not a particular intrusion into a person’s privacy constitutes a “search” for the purposes of the 4^th Amendment. The 4^th Amendment to the Constitution enshrines one of the most important freedoms that Americans enjoy: the right to be free from arbitrary and unreasonable searches of their private property, especially their homes. This right exists to protect privacy, and limit government power.

Of course, the people who wrote the 4^th Amendment recognized that the authorities sometimes need to conduct searches of private homes when they have good reason to believe that the house contains illegal items, or evidence of a crime. For that reason, there is a procedure whereby police can search private homes. With a few exceptions, authorities need to get a search warrant before they can search a home, and a judge can only issue a search warrant if there is “probable cause” to believe that the thing the authorities are looking for is there. This is not a high standard of proof, but it does require the authorities to demonstrate that they have a good reason to believe that they’ll find what they’re looking for at the place to be searched.

Some minor intrusions into personal privacy, however, are not considered “searches,” and therefore do not require a warrant. The question in this case is whether or not a dog standing on a doorstep, and smelling the air inside the house to detect contraband, constitutes a search.

Federal and state courts generally haven’t found any fault with the use of dogs to search automobiles that have been pulled over or luggage at airports, and other semi-public places. However, these are both situations in which your reasonable expectation of privacy is significantly reduced. While the police can’t perform searches in these contexts willy-nilly, they generally do not need search warrants, and a fairly low level of suspicion is required in order to validate a search in these situations.

But private homes are supposed to be sacrosanct. Unless the police are responding to an immediate emergency, or a resident consents to a search, they have to go to a court and get a warrant before they can search a home. And a warrant can only be granted if the authorities convince a judge that there is probable cause to justify a search. Up to now, a dog standing outside a home, and signaling the presence of contraband inside the home, has commonly served as the probable cause needed to secure a warrant. But, is that dog sniff a “search” which itself requires a warrant?

The case that’s probably most instructive is the one I already briefly mentioned: Kyllo v. United States. In that case, the police used a thermal imaging camera to look for “hot spots” on a suspect house – areas which were radiating more heat than the rest of the house – indicating that marijuana is being grown in one of the houses (the cameras are detecting the heat given off by the lights necessary to grow a large number of plants indoors).

The Supreme Court ruled that using a light-sensing camera to obtain information about what’s happening inside a house constitutes a search, and therefore requires a warrant.

A dog smelling the air outside a house, looking for signs that contraband is hidden in the house, seems analogous. However, this technique has been used by police far longer than heat imaging cameras, for obvious reasons. Police departments have come to rely on this technique to obtain the probable cause necessary to secure a search warrant. And we aren’t just talking about illegal drugs, either. Dogs can be trained to smell explosives, allowing them to tell if a house or apartment is being used by bomb-makers or terrorists, so a lot more can be at stake than catching pot growers.

I’m actually pretty torn as to how the court should rule in this case. On one hand, I think the right to privacy is an essential element of a free society. On the other hand, I recognize that the use of trained dogs has long been a valuable (and adorable) method of detecting and preempting crime. Disrupting the use of this valuable tool could have unforeseen consequences.

Whatever the result, you can bet that I’ll be watching this case closely, and will probably revisit it as it develops.