All posts for the month November, 2014

In Heien v. North Carolina, the Supreme Court will decide whether reasonable suspicion to stop a vehicle can be based on a police officer’s reasonable mistake of law.  In this case, the sergeant observed the defendant driving with only one brake light and, believing that this violated North Carolina traffic laws, the sergeant pulled the car over.  The familiar pattern of a consent search and discovery of drugs followed in due course.  At trial the defendant argued that he was not in fact in violation of the traffic laws and therefore the stop was unconstitutional.  The lower court disagreed, holding that it was in fact illegal for the defendant to drive with only one brake light, but the intermediate appellate court reversed, engaging in a lengthy discussion of the North Carolina Traffic Code an ultimately concluding that a driver may legally operate a car with only one brake light.  Thus, the appellate court concluded that the stop was unconstitutional and therefore the drugs should be suppressed.

brake light North carolina law 2


The prosecution appealed to the North Carolina Supreme Court, but interestingly enough, it did not appeal the question of whether it is legal to drive with one brake light.  Instead, it argued that the stop was constitutional because the sergeant had a reasonable and good faith belief that the defendant was breaking the law.  In a 4-3 decision, the court agreed with the government’s position and upheld the search:

We are not persuaded that, because Sergeant Darisse was mistaken about the requirements of our motor vehicle laws, the traffic stop was necessarily unconstitutional.  After all, reasonable suspicion is a “commonsense, nontechnical conception [] . . . on which reasonable and prudent men, not legal technicians, act,” and the Court of Appeals analyzed our General Statutes at length before reaching itsconclusion that the officer’s interpretation of the relevant motor vehicle laws was erroneous.

Many of those who oppose the decision of the North Carolina Supreme Court (including the three justices who dissented) argue that allowing a reasonable mistake of law to form the basis of reasonable suspicion would represent a significant step in the perceived erosion of our Fourth Amendment rights.  For example, the dissent argued that the majority’s decision would apply:

when the officer acts based on the misreading of a less innocuous statute, or an incorrect memo or training program from the police department, or his or her previous law enforcement experience in a different state, or his or her belief in a nonexistent law.

But this is surely not the case.  A police officer’s “belief in a nonexistent law” could not possibly be considered reasonable.  And a mere “misreading” of a law is not reasonable—Sergeant Darisse’s mistake was only deemed reasonable because a trial court later agreed with it and the appellate court needed pages of sophisticated statutory analysis to determine that both the Sergeant and the trial court were wrong.  And if the police officer is basing his or her belief on “an incorrect memo or training program from the police department,” this does not make the mistake reasonable; it simply means that the unreasonable mistake was made by someone else in the police department.  (In Herring v. United States, the Supreme Court held that the exclusionary rule should not be applied in such a case because the officer acted in good faith, but that is a question of remedies, not rights.  For a good analysis of this “right/remedy” distinction in the Heien case, see this blog post by Professor Rory Little).

In reality, if the Court finds that a reasonable mistake of law can be the basis of an officer’s reasonable suspicion (which it probably will), the impact of this decision will be quite limited.  When is a court going to deem that a police officer’s mistake of law is reasonable?  Almost never.  Although the North Carolina Supreme Court rejected the defendant’s position that a police officer’s mistake of law is always unreasonable, it implied that a police officer’s mistake of law is almost always unreasonable.  Heien was a very unusual case, involving an ambiguous law and a rather unexpected interpretation of the law by a appellate court.  Most of the mistakes of law made by police officers (which are probably relatively rare in the first place) would not meet the reasonableness standard.

As many commentators have noted, reasonableness is becoming more and more significant in the Court’s Fourth Amendment analyses.  In the past two years alone, the Supreme Court has applied a reasonableness test to preclude detention of suspects not present at the site where a search warrant is executed; to prohibit a per se finding of exigency to take blood samples in drunk driving cases; to allow strip searches and for those arrested for minor crimes; and to allow DNA tests for those arrested of felonies.  In each of these cases, the Court avoided applying a bright-line test and instead balanced the competing interests of law enforcement and the privacy rights of suspects.  From the questions at oral argument, it appears the Justices will follow the same course in this case as well.


One of the more interesting Fourth Amendment issues created by our ubiquitous use of cell phones involves law enforcement obtaining historical records of our cell phone’s location in order to determine where we were at any given time in the past.  The Eleventh Circuit recently ruled in United States v. Davis in that the government must obtain a warrant before it can access this information; the case is now on appeal to the entire circuit en banc.

cell phones       time machine

This issue has already been considered by the Third Circuit and the Fifth Circuit, both of which refused to apply the Fourth Amendment to the acquisition of historical cell phone location data.  But in Davis, the government received over 11,000 records of the defendant’s location–one for every eight seconds during the sixty-seven days covered by the records.  In order to acquire these records, the government did not seek a warrant, because the prosecutor argued that under the third party doctrine of Smith v. Maryland, a warrant was unnecessary. (The government did obtain a “D-order” under 18 U.S.C. § 2703(d) of the Stored Communications Act, which only requires that the government demonstrate “specific and articulable facts” that the information is “relevant and material” to an ongoing criminal investigation).

The judgment of the Davis case is consistent with Justice Alito’s concurring opinion in United States v. Jones.  The Jones concurrence held that although following a car over public highways for one trip was not a Fourth Amendment “search,” tracking the movements of a person’s car over public highways for one month did constitute a search.   In Davis, the government tracked the defendant’s movements for sixty-seven days; thus, under the mosaic theory of the Fourth Amendment, tracking the defendant for such an extended period of time violated his reasonable expectation of privacy.   Thus, there is a good chance that on these facts, the Eleventh Circuit might uphold the judgment of the three-judge panel.

But the underlying holding of the Davis case did not rely on the mosaic theory.  The court went further and held that any use of cell phone location data constituted a search:

“Davis has not voluntarily disclosed his cell site location information to the provider in such a fashion as to lose his reasonable expectation of privacy.

In short, we hold that cell site location information is within the subscriber’s reasonable expectation of privacy. The obtaining of that data without a warrant is a Fourth Amendment violation. Nonetheless, for reasons set forth in the next section of this opinion, we do not conclude that the district court committed a reversible error.”

The ACLU has duly filed an amicus brief for the en banc appeal in Davis, urging the panel to let the original decision stand.  A lawyer for the ACLU explained their position in a recent article in the Wall Street Journal:

“[Cell phone location information] gives the police a power that they have never had before in the history of law enforcement, which is a time machine into where somebody was going and what somebody was doing in the past,” said Nathan Freed Wessler, an American Civil Liberties Union lawyer who has also filed a brief in the case. “It’s an incredibly powerful investigative tool. And with an appropriate warrant police can get that, but what is absolutely essential is they can’t just sort of walk their way into that time machine without demonstrating probable cause.”

Thus, according to the Eleventh Circuit’s opinion, the government should never be able to use the positional information from our cell phones to learn our past location, even if the government is only seeking records from one specific point in time.  The ACLU argues that this is analogous to using a “time machine” to spy on our past movements, and argues that police have never before had this power.  But this is surely an exaggeration.   This type of “back-dated” surveillance is quite common.  Surveillance cameras in public places have been around for decades.  And the government has routinely used historical data to track the past movements of suspects–they could tell when a certain car entered a parking garage or crossed a toll bridge; they could check the person’s home phone logs and determine whether the person was present at home at a certain time;  they could tell when a person punched in at work; and so on.

As is usually the case, the difference between historical cell phone location data and other, more familiar types of historical surveillance is a difference in degree, not kind.  Cell phone location data makes law enforcement more efficient–if the police want to know whether a suspect was at a certain location at a certain time, they are much more likely to be able to determine that fact now than they were in the past with more traditional techniques.  As the government notes in its brief, this type of information can absolve the innocent as well as inculpate the guilty; the innocent suspects would then be spared being the subject other, far more intrusive surveillance and investigative techniques.

If we apply the Katz test to this question, it seems unlikely that an average person would believe that they have a reasonable expectation of privacy in their physical location.  The vast majority of people make no secret of their physical location at any given time; the very idea that their location should be kept secret would strike them as strange.  It is only when the government is trying to obtain massive amounts of information covering an extended period of time that the mosaic theory kicks in that the government begins to learn truly private information about the person, thus transforming this surveillance into a Fourth Amendment search.

Granted, there are certain times when individuals–both the innocent and the guilty–would like their location to be secret.  But if that is the case, we would expect a reasonable person to take precautions so that others would not know where he or she was.  In the past, that would perhaps mean wearing a disguise, or sneaking away at night, or avoiding populated areas.  In the modern era, it now also means turning a cell phone off, or leaving the cell phone at home, or using a cell phone that cannot be traced back to its user.  This requires extra effort on the part of the individual who wishes to remain hidden,  but–again–this is not a new phenomenon.  For example, assume a person wishes to make a secret trip to a motel.  The most convenient method of doing so would be for her to drive her own car and park it outside the motel.  But this runs the risk of somebody seeing  the license plate on the car, either while it is being driven or while it is parked outside.  Thus, to ensure secrecy, the person must either walk, or use a different car, or park some distance from the motel.  Does imposing these restrictions mean that the person’s reasonable expectations of privacy are being violated?  Should we therefore preclude police from the conducting  warrantless checks of the license plates of cars that are in public view?

Certain technological advances–such as cars and cell phones–have become ubiquitous because they provide an enormous increase in convenience.  As it turns out, these advances also provide the police with more efficient tools to conduct criminal investigations.  As long as these tools are not revealing previously secret, hidden, private information (and a person’s physical location does not seem to fit into that category), it makes sense to allow the police to use these tools to save resources, track down the guilty, and exonerate the innocent.


Earlier this year, a man was removed from a movie theatre and detained by Immigration and Customs Enforcement (“ICE”) and local police officers because he was wearing his Google Glass while watching the movie.  Law enforcement officers believed he had been using the device to record the movie.  According to the Glass owner, he was detained and interrogated for hours; ICE would only say that he had been “briefly interviewed” and “voluntarily” answered questions.  The incident was resolved when–with the owner’s consent–an ICE officer plugged the Google Glass into a laptop and scrolled through the contents, finding no evidence that he had videotaped the movie. google glass               ICE logo

The incident got a lot of attention online, mostly consisting of sympathy for the Glass owner and hostility towards the law enforcement officials who conducted the seizure and search.  On the surface, this criticism seems warranted–the man’s seizure  certainly appears to be illegal, and the “consent” he gave for the search while being illegally detained would certainly be invalid.  Also, the officers’ tactics seemed to be a bit heavy-handed: there were somewhere between four and twelve law enforcement officers total; they allegedly berated the man with questions about his personal life and his employment; they refused to let his wife know where he was or what was happening, and so on.  Undoubtedly, there were gentler (and probably more effective) ways of handling the situation.

But the legal question turns out to be a bit more complex upon further examination.  Was the seizure in fact illegal?  Law enforcement officers are allowed to arrest a person if they have probable cause to believe that he or she is committing a crime.  If the man had been pointing a video camera at the screen, there would be no question that he could be seized.  If he had been holding his smart phone up and pointing it at the screen, that would also likely constitute probable cause.  At the time of this incident, Google Glass was a fairly new device, and it was extremely unusual for someone to outfit them with prescription lenses (as this man had in fact done).  Thus, when the manager of the movie theater–and later, the ICE officers–saw a man wearing Google Glass to a movie, they had no reason to think that he was actually using them as prescription glasses.  And although there were other possible reasons for him to be wearing the device during the movie (to surf the internet while watching the movie, or perhaps check his email during the slow scenes), the most reasonable assumption is that he was using Google Glass to record the movie.  In this case, of course, the assumption was wrong, but that doesn’t mean that ICE didn’t have probable cause in the first place.  Law enforcement officers have made legal arrests on far less evidence than they had in this case.

Thus, the interesting thing about the Google Glass incident is not that the law enforcement agents were acting beyond their legal powers (a situation which regrettably occurs in many situations, even outside the context of law enforcement), but that in fact the law probably did give them the right to act in this way.  Most observers will say that this conclusion makes the Google Glass incident far more troubling; some will conclude that probable cause analysis should be changed or tweaked when devices such as this are involved. But it is useful to look at the situation from the law enforcement perspective: if ICE officers are tasked with detecting and preventing movie piracy, what other options did they have?  They could have requested that the man remove his glasses–but he might have simply refused the request (and at any rate, a law enforcement officer’s only recourse when faced with someone who is likely committing a crime has to be more than asking the suspect to stop committing the crime).  Unless movie theaters choose to ban Google Glass from all of their theaters, the device has given potential movie pirates an opportunity to surreptitiously record any movie while claiming that the device is equipped with prescription lenses.  This may not bother many people, since movie piracy is not viewed as a particularly serious crime, but this is not the only context in which new technology can change the balance of power between law enforcement and criminals.  The past few decades have given all of us–including criminals–the ability to record, transmit, and store data in ways that far outstrip the ability of law enforcement officers to investigate crime using traditional methods.