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Argument preview: Dog sniffs and traffic stops – once more to the Fourth Amendment well

Prior decisions of the Supreme Court addressing the constitutionality of the use of narcotics-sniffing dogs versus other law enforcement techniques have been on a theoretical collision course for years.  On Wednesday, the Court will hear argument in Rodriguez v. United States and consider aspects of the issue once again: does the Fourth Amendment restrict the use of drug-sniffing dogs by the police at a roadside traffic stop, when the officer has finished issuing any citation and the stop is prolonged for a few minutes solely to conduct the dog sniff?

The nuances of simple facts

As in many Fourth Amendment cases, although the facts in Rodriguez are relatively simple they raise difficult theoretical questions which often turn on nuances about the details.  One evening shortly after midnight, a car being driven by Dennys Rodriguez and carrying passenger Scott Pollman was stopped by Officer Morgan Struble.  Struble had observed the car drift slowly onto the shoulder of a highway and then jerk suddenly back onto the road — this was concededly “probable cause” to believe that Nebraska traffic statutes had been violated.  Coincidentally, Officer Struble was a “canine officer,” and he had his drug-sniffing dog with him in his patrol car.

Upon questioning, Rodriguez told Officer Struble that he had swerved to avoid a pothole; the officer found that implausible.  The officer was also suspicious of the “overwhelming” odor of air freshener; and he thought Pollman was unusually nervous for a passenger.  When the officer asked Rodriguez to come sit in the patrol car during a records check, Rodriguez asked if he was required to do so.  Upon being told that he was not, Rodriguez stayed in his own car.

When the records check came back negative, the officer went back to Rodriguez’s car and spoke with Pollman, a conversation that the officer later said he also found suspicious.  When the officer returned to his car, this time to run a records check on Pollman, he called for a second officer to come to the scene:  Officer Straube had apparently decided to conduct a dog sniff and wanted another officer as “back up” for safety reasons.

Officer Struble then went back to Rodriguez’s car, returned all documents to both men, and issued Rodriguez a written warning.  At this point the stop of the car for traffic reasons appears to have been over.  Officer Struble then asked for permission to walk his dog around the car.  When Rodriguez refused, Officer Struble ordered him out of the car.  This also concededly appears to be a moment of Fourth Amendment detention.  They waited for the second officer, and when that officer arrived the dog sniff was conducted.  The dog alerted within a few seconds.  A search of the car yielded a bag of methamphetamine and the case went federal.  Undisputedly, about seven or eight minutes elapsed from when Officer Struble gave Rodriguez the written warning until the dog alerted.

The federal magistrate found that the facts did not add up to reasonable suspicion once the traffic stop was over.  Nevertheless, he recommended against suppression because the delay to conduct the dog sniff was a “de minimis intrusion” under Eighth Circuit precedent.  The federal district court agreed, Rodriguez then pled guilty conditionally, and on appeal the Eighth Circuit affirmed.

Thus the question whether the Fourth Amendment permits an eight-minute detention, after a valid traffic stop has been completed, to conduct a dog sniff, seems clearly presented.   More generally, the question whether (and for how long) a traffic stop may be prolonged, for reasons unrelated to the traffic violation itself, has divided lower courts.  Note however, that the question in Rodriguez is premised on the assumption that the officer on the facts of this case did not have “reasonable suspicion” regarding narcotics.  In addition to arguing that the dog-sniff detention was reasonable under the Fourth Amendment, the United States also argues that the Court could alternatively find that there was, as a matter of law, “reasonable suspicion” here.  If the Court were to accept that view, then the “detention for dog sniff without suspicion” question would presumably be moot.  But given the views of the trial judges, this alternative seems unlikely (although it could be open if there were a reversal for Rodriguez and remand).

The constitutional collision course

Here’s a brief sketch of the constitutional debate regarding dog sniffs.  The Fourth Amendment concept of a “search” is a constitutional trigger for inquiring into further requirements (“probable cause,” “reasonable suspicion,” possibly a search warrant, or some recognized exception).  Absent a “search” (or “seizure”), officers are not restricted by the Fourth Amendment at all.  Thus if a dog sniff is not a “search,” then there are no Fourth Amendment constraints on officers employing them (although this still leaves the question of the length of the detention here).

In two prior cases, Illinois v. Caballes (2005) and United States v. Place (1983), the Court has declared that dog sniffs conducted by law enforcement in public places (an airport and a roadside traffic stop) are “not a search” because (the Court said) they don’t intrude upon a “reasonable expectation of privacy.”  More recently, however, the Court has ruled that using a drug-sniffing dog on a residential front porch (Florida v. Jardines, 2013) is a “search,” regardless of privacy interests.  Meanwhile the Court has ruled more generally that using a GPS locator to monitor cars on public roads (United States v. Jones, 2012) is a “search;” and that employing a “thermal heat imager” from a police car on a public road (Kyllo v. United States, 2001) is a “search” when it detects information about heat usage inside a house.  Although the Caballes decision suggests a constitutional difference between a heat imager and a drug-sniffing dog,” the case involved the sniff of a car in a roadside rather than the sniff of a residence.  Perhaps the relevant constitutional distinction is really between cars and houses?  Wednesday’s argument may – or may not – shed further light on these questions.

The other constitutional aspect of Rodriguez asks what Fourth Amendment rules apply to the detention of cars and their passengers during roadside traffic stops.  Prior to 1968, when Terry v. Ohio was decided, the accepted doctrine was that an officer may not stop a car unless he has “probable cause” — but if an officer does have probable cause to believe a car contains contraband, he may stop and search a car without a warrant, on the theory that its mobility creates an “exigency” and there is not time to seek a warrant.  Terry, however, reduced the level of suspicion necessary under the Fourth Amendment to “stop” (that is, “seize”) a person, ruling that a brief detention to either confirm or allay suspicion is constitutionally acceptable if the officer has articulable “reasonable suspicion” that crime is afoot (a somewhat undefined standard that is more than a hunch but less than probable cause).

In 1985, the Court ruled in United States v. Sharpe that a twenty-minute detention of a car and its occupants upon reasonable suspicion was acceptable when there was “no delay unnecessary to the investigation” of the suspicion.  And in Caballes, the Court upheld the dog sniff at a roadside traffic stop because, even though the sniff was not related to the suspicion of a traffic violation, the dog sniff (which is “not a search”) was conducted while the traffic investigation was ongoing, so that the detention was not “unnecessarily prolonged.”

If you’re still with me, the last relevant theoretical point is that Justice Antonin Scalia has long been leading, within the Court, a re-evaluation of Fourth Amendment doctrine in favor of privacy (and thus often in favor of criminal defendants).  He authored Kyllo and Jardines and Arizona v. Hicks (finding a slight movement of stereo equipment to be a “search”), and has been a pro-defendant dissenter in other leading Fourth Amendment cases.  (For example, when the Court ruled in Maryland v. King (2013) that officers may take a DNA “cheek swab” incident to an arrest without any further suspicion, Justice Scalia protested that “I doubt that the proud men who wrote the charter of our liberties would have been so eager to open their mouths for royal inspection.”)  So his questions at Wednesday’s argument may be the bellwether for where the Court is going with Rodriguez.

The arguments of the parties and amici

Represented by David Stickman, the Federal Public Defender for Nebraska, Rodriguez argues that when a motorist is stopped for a traffic offense, any detention beyond the time needed to complete the traffic investigation is a “seizure” that requires at least “reasonable suspicion.”  He argues that there is no “de minimis” exception to the Fourth Amendment and that a “bright line” is needed for officer, citizen, and judicial simplicity alike.  Thus, argues Rodriguez, it is irrelevant whether a dog sniff is a search, because the detention during which it occurred here was unconstitutional.  This argument smartly avoids having to argue that Caballes or Place should be overruled.  (Rodriguez also argues that the federal judges accurately found that no independent “reasonable suspicion” was present to justify the further detention.)

The federal government argues that a distinction turning on when, exactly, a traffic investigation is “complete” is artificial, unnecessary, and will lead to administrative confusion.  Instead, the government argues for a rule that “a range of investigatory” activities is permitted under the Fourth Amendment during a traffic stop, so long as (drawing upon the Court’s statement in Caballes) the traffic stop is not “unnecessarily prolonged.”  The government notes that the Court has previously upheld investigatory activities “unrelated to the traffic violation,” in Caballes and also in Arizona v. Johnson (questioning of passengers about other matters).

Given that unrelated investigation can occur, the government argues that seven or eight minutes is not unreasonable (nor was the half-hour length of the entire stop here), and it should not matter whether an officer hands a citation to the driver and then conducts a dog sniff, or holds on to the citation and conducts a dog sniff before completing it.  The government notes that some officers, as well as their record checks, computers, and other equipment, are faster or slower than others; the overarching relevant question under the Fourth Amendment is whether the duration and diligent execution of the stop are “reasonable.”  (The government also argues that the specific facts of this case did indeed give Officer Struble “reasonable suspicion” to suspect drugs, and that because this is a question of law reviewed de novo on appeal the trial court’s resolution of the question is not dispositive.)

One amicus brief was filed in support of each side.  While the parties avoid the question whether a dog sniff is a “search,” the U.S. Justice Foundation argues in support of Rodriguez that the Jardines and Jones decisions should call Caballes into question on this point, and that a dog sniff of one’s car should not be allowed without independent Fourth Amendment justification.  Pitching a portion of its argument, apparently, at common-law enthusiasts such as Justice Scalia and Justice Clarence Thomas, this amicus brief cites political philosopher John Locke from 1690 (about property rights, not cars, of course).

Meanwhile, an amicus brief on behalf of twelve states argues in support of Nebraska that reasonableness should be decided on a “totality of the circumstances” basis, and that any line requiring examination of when a traffic stop is “complete” will adversely affect officer safety, provide “perverse incentives” to slow down traffic stops, and lead to confusion and difficulties given the “vastly differing characteristics” of law enforcement agencies, policies, and resources across the country.  On a “totality” view, this detention was not unreasonable and dog sniffs conducted quickly during traffic stops do not violate the Fourth Amendment.


Because the parties’ positions are starkly opposed, and the Court’s Fourth Amendment precedents do not speak with crystal clarity, the course of tomorrow’s argument is difficult to predict.  Perhaps it will look simple and clear – that police either can, or cannot, prolong a traffic stop to quickly conduct a dog sniff.  Or just as likely, the Justices will express differing perspectives, each invoking their favorite Fourth Amendment precedents, leaving the opinion to whoever wants to champion a point of view that four others can support.  It is often unclear whether a Fourth Amendment case is a “big” one until years after its implications have played out.  Rodriguez could provide an opportunity for clear new doctrine, or it could simply be another pathstone on the long, and unending, Fourth Amendment road.

Recommended Citation: Rory Little, Argument preview: Dog sniffs and traffic stops – once more to the Fourth Amendment well, SCOTUSblog (Jan. 21, 2015, 3:12 AM),