A lot has been written on GPS tracking – both on the blog (here and here and here, for example) and the media (here and here, for example). The warrantless use of GPS tracking devices is one of the cutting edge issues in Fourth Amendment law today, I believe.
A bit a refresher on the law may be worthwhile here. The leading case is United States v. Knotts. In that case, the defendant and his co-conspirators were suspected of manufacturing methamphetamine. Law enforcement officers contacted the chemical company where the conspirators purchased their chemicals for the manufacture of the drug. With the consent of a chemical company, officers installed a tracking device inside a five gallon drum of chemicals. When Knotts' co-defendant purchased the drum of chemicals, officers were able to made the purchase officers were able to follow the car, "maintaining contact by using both visual surveillance and a monitor which received the signals sent from the beeper."
The Supreme Court held that a warrant was not required to track the vehicle using the type of device at issue in Knotts. The Court reasoned that, for Fourth Amendment purposes, no reasonable privacy interest exists in the movement of a vehicle traveling on a public roadway because drivers voluntarily convey to the public their location and direction of travel. The key to the analysis in Knotts is the premise that persons have no legitimate expectation of privacy in their location if they could lawfully be viewed by law enforcement. The Court explained:
Visual surveillance from public places . . . would have sufficed to reveal all of these facts to the police. The fact that the officers in this case relied not only on visual surveillance, but on the use of the beeper to signal the presence of [the] automobile to the police receiver, does not alter the situation. Nothing in the Fourth Amendment prohibited the police from augmenting the sensory faculties bestowed upon them at birth with such enhancement as science and technology afforded them in this case.
Implicit on this premise is that law enforcement is permitted to use technology to enhance permitted visual surveillance. The Court compared the use of the beeper to the use of a searchlight in a previous decision to observe contraband on the deck of a ship. The use of other technology, such as helicopters, airplanes, and satellites is merely just another enhancement of visual surveillance.
Although a first view of Knotts seems to suggest that the Court would approve the warrantless use of GPS devices, the Knotts Court stopped short of permitting the type of surveillance permitted by GPS devices. The warned that the opinion did not reach "dragnet type law enforcement practices." Justice Stevens wrote a concurring opinion to emphasize his view that there was a limit to police use of technology. He said, "Although the augmentation in this case was unobjectionable, it by no means follows that the use of electronic detection techniques does not implicate especially sensitive concerns."
Prior to august 2010, based on Knotts, the Federal courts that have considered the question of GPS monitoring have universally permitted the placement and use of the devices on public streets. State courts were divided, but those courts seeking to limit the warrantless use of GPOS devices generally relied on their own state constitutions rather than finding a Fourth Amendment violation. However, in August 2010 the DC Circuit decided United State v Maynard. The Maynard court found that the warrantless use of a GPS tracker over an extended period of time violated the Fourth Amendment. The court distinguished Knotts on the grounds that "the whole of one's movements over the course of a month is not actually exposed to the public because the likelihood anyone will observe all those movements is effectively nil." The court explained:
It is one thing for a passerby to observe or even to follow someone during a single journey as he goes to the market or returns home from work. It is another thing entirely for that stranger to pick up the scent again the next day and the day after that, week in and week out, dogging his prey until he has identified all the places, people, amusements, and chores that make up that person's hitherto private routine.
According to the Maynard court, the difference between discrete and long-term surveillance is significant because "the whole of one's movements . . . . reveals more -- sometimes a great deal more -- than does the sum of its parts."
That background makes the decision by Judge Young in Massachusetts very interesting. In United States v Sparks, the FBI was investigating the defendant for a series of a bank robberies. On the same day, the FBI had initiated surveillance through the use of an affixed GPS device on the defendant's car, another bank was robbed. According to the court, the Agents soon "found themselves in the most fortuitous of positions:" they ob served suspects matching the description of the bank robbers get into the car. The GPS device allowed the car to be located on I-95 and the police initiated a stop, but the suspects fled on foot. The defendant's wallet was found in the car, and the GPS device on the car indicated that the vehicle was near the defendant's apartment on the morning of the robbery.
Relying on Knotts, the Sparks court concluded that the monitoring of the GPS device on the defendant's vehicle "does not implicate any privacy interests and cannot be considered a search." The court reasoned that the GPS device, like the tracker in Knotts, merely augments the sensory abilities of law enforcement officers. The court found the reasoning of Maynard "legally unconvincing." The judge was critical of the decision:
The court in Maynard, however, leaves police officers with a rule that is vague and unworkable. It is unclear when surveillance becomes so prolonged as to have crossed the threshold and created this allegedly intrusive mosaic. What's more, conduct that is initially constitutionally sound could later be deemed impermissible if it becomes part of the aggregate. Finally . . . a rule prohibiting prolonged GPS surveillance due to the quantity or quality of information it accumulates would also incidentally outlaw warrantless visual surveillance and this Court is unwilling, and unable, to extend the reach of the Fourth Amendment that far.
There is a factual distinction between Sparks and Maynard that bears emphasis: the GPS device in Sparks was used over a short period of time to reestablish visual contact with the defendant. In contrast, in Maynard the surveillance was continuous over a period of weeks. However, I think it is more important that Judge Young did not find the reasoning o. However, I think it is more important that Judge Young did not find the reasoning of Maynard persuasive.
Is Sparks an indication that the reasoning of Maynard is not likely to be followed? We will see . . .