This week the Court decided Rodriguez v. United States, and held in a 6-3 decision that the police cannot prolong a traffic stop even for a few minutes in order to conduct a drug dog sniff.  More broadly, the Court held that the duration of a traffic stop, like the duration of a Terry stop, must be “reasonable,” and thus may not be lengthened by police conduct which was beyond the “mission” of the traffic stop.

In my preview of this case, I predicted that the Court would be forced to define what is “reasonable” by essentially legislating from the bench and listing precisely the actions that officers can and cannot do during a routine traffic stop.   I wrote that the Court would define “reasonableness” as “what we are used to seeing the police doing, rather than what is actually reasonable for the police to do.  Thus, in this case, well-established practice will create the constitutional rule, rather than (as it should be) the other way around.”

My prediction was mostly correct, but I give the Rodriguez Court credit for at least trying to create a principled distinction between what is “reasonable” during a traffic stop and what is not.   Specifically, the Court said that the police officer may take a reasonable amount of time to “address the traffic violation that warranted the stop;” to “attend to related safety concerns;” and to conduct “ordinary inquiries incident to [the traffic] stop.”  This last category is included to allow police to “ensure that vehicles on the road are operated safely and responsibly.”  In contrast, the police officer is not allowed to take any extra time to “detect evidence of ordinary criminal wrongdoing.”  The Court used these guidelines to conclude that it is impermissible to take extra time during a traffic stop to use a drug dog.

Unfortunately, the Court’s attempt at making a principled distinction falls short.  The Court helpfully provides a list of what falls under the “ordinary inquiries” category: checking the driver’s license, inspecting the automobile’s registration and proof of insurance, and determining whether there are outstanding warrants against the driver.  But as Justice Thomas points out in his dissent, this last action–checking for warrants–does not really ensure that the vehicle is operated safely and responsibly–it is, plain and simple, an investigation into whether the suspect has been involved in criminal activity.  As such, it seems indistinguishable from the drug dog sniff, at least under the paradigm provided by the Court.

Interestingly, Rodriguez appears to limit another common activity during a traffic stop–questioning the suspect in order to learn if the suspect is engaged in criminal activity and/or requesting to search the car.  The Court does note that the police may “conduct certain unrelated checks during an otherwise lawful traffic stop,” but it states that “[s]he may not do so in a way that prolongs the stop, absent . . . reasonable suspicion.”  Thus, Rodriguez seems to prohibit any investigatory questioning unrelated to the reason behind the stop which prolongs the length of the stop.  It will be interesting to see how lower courts interpret this aspect of the case–does this mean that if the police officer has completed the warrant check and the citation, she is not allowed to ask any further investigatory questions of the driver unless they are somehow related to the offense?  Or maybe lower courts will interpret Rodriguez even more strictly.  As Professor Rory Little notes at SCOTUSblog: “the Court says only that an officer ‘may conduct certain unrelated checks’ during a stop, without discussing what limitations ‘certain’ may imply.  The majority also says that ‘on-scene investigation into other crimes … detours from that mission’ of traffic safety.”  Lower courts will have to interpret this language to determine which questions are or are not permitted to lengthen a traffic stop.

Professor Little also discusses another “loose end” in the Rodriguez decision: he sees the case, when considered alongside the rejection of the front-door dog-sniff in Jardines, as evidence that the Court is backing away from its 1983 decision United States v. Place which stated that drug dog sniffs are not a Fourth Amendment search.  (This would also mean, presumably, that the Court is backing away from its affirmation of Place in the 2005 decision of  Illinois v. Caballes).  He calls Place “one of the more extreme extensions of the ‘reasonable expectation of privacy’ test,” and argues that its rationale is now suspect in light of Jardines, Riley v. California (which prohibited searching cell phones incident to a lawful arrest), and Kyllo v. United States (which prohibited warrantless thermal imaging of a home).   These cases, Little notes, are evidence that the Court has “recognized that privacy has some scope beyond ‘expectations’ that the real world may compel us to abandon,” and that the Court is coming to the realization that drug dogs are like any other investigative tool and should be treated as such.

I am not so sure about this conclusion.  The Court’s rationale that drug dog sniffs do not constitute a Fourth Amendment search is based on a very specific doctrine–the binary search doctrine–and nothing in Kyllo, Jardines, or Riley affects that doctrine in any way.  The binary search doctrine states that government surveillance is not a Fourth Amendment search if it is only able to reveal the absence or presence of illegal activity.  The doctrine is based on the theory (first discussed in Rakas v. Illinois) that the Fourth Amendment only protects legitimate expectations of privacy.  In contrast, the Court’s recent limitations on the use of drug dogs have been based on other doctrines.  In Jardines, the limitation was based on the new  “trespass” Fourth Amendment test found in Jones; and in Rodriguez, the limitation was based on the doctrine that although a drug dog sniff is not a Fourth Amendment search, it is a Fourth Amendment seizure.  All that Rodriguez stands for is that the seizure aspect of the drug dog sniff needs to be justified by reasonable suspicion, and that any unreasonable delay that prolongs a seizure in order to conduct a drug dog sniff is unconstitutional–which is exactly what the Court held in Place thirty-two years ago.

NOTE:  Other commentators have also reacted to this case:  Orin Kerr has stated that he believes the case is correctly decided and that the Court was wise to adopt the “safety-based rationale” for traffic stops, while Steven Schwinn discussed the case on the Constitutional Law Prof Blog.