Police Need a Warrant for GPS Tracking

The U.S. Supreme Court’s 2012 term will likely go down in history as one of the most important and eventful Supreme Court terms in decades. It is hearing cases having to do with healthcare, immigration, and many other important topics.

And today, the Court delivered a very interesting and important decision about the 4^th Amendment right to be free from unreasonable searches and seizures: it has held that, for police to place a GPS tracker (or, presumably, any other device capable of tracking a car’s location), they must obtain a search warrant. In a rare unanimous ruling, the Court held that tracking a car with a GPS device is a “search” for the purposes of the 4^th Amendment. The opinion can be found here (.PDF).

The surreptitious use of tracking devices has been a very important tool for law enforcement for decades. It allows the police to see where a suspect’s vehicle is driven, and when. Obviously, this information can prove extremely useful in some criminal investigations.

The 4^th Amendment to the constitution enshrines the right of individuals to be secure from “unreasonable search and seizure,” and it says that search warrants cannot be issued without probable cause. Note, however, that it does not say when a warrant is required to conduct a search, or even if a warrant is required. However, over the years, the courts have carved out a rule that seems to work pretty well: a search conducted without a warrant is presumed to be unreasonable, and therefore unconstitutional, with a few very specific exceptions (consent from the owner or resident of the property to be searched, for example).

So courts often have to determine whether or not a particular act constitutes a “search” for the purposes of the 4^th Amendment. For example, courts have ruled that using infrared cameras to peer inside a person’s house constitutes a “search,” and therefore requires a warrant. On the other hand, they have held that a police officer walking by a house, and happening to see illegal activity through a window or open door, does not constitute a search, and that information obtained via such means can be used in court whether or not there was a search warrant.

So, does tracking a car via GPS constitute a search? The Court said yes. Writing for the Court, Justice Scalia boiled down his position to this: “It is important to be clear about what occurred in this case: The Government physically occupied private property for the purpose of obtaining information.  We have no doubt that such a physical intrusion would have been considered a ‘search’ within the meaning of the Fourth Amendment when it was adopted. “

The court seems to be focusing on the fact that, in order to obtain this location information, the government had to make a significant intrusion into the private property rights of the defendant. It spent less time dwelling on the question of whether or not the defendant had a reasonable expectation of privacy with respect to his car’s location on a public road.

The Supreme Court has noted that their 4^th Amendment analysis doesn’t rest entirely on the law of property. For example, an overnight houseguest at your home has the exact same 4^th Amendment rights with respect to the belongings he has in your home as you would. This is the case even though he has no property interest in the home being searched. Instead, it’s the defendant’s privacy rights that the court is looking at.

However, that does not mean that property rights can’t enter the equation, as illustrated in this case.

So, what does this mean? Well, it shows that, when it comes to privacy rights with respect to the 4^th Amendment, there is a lot of common ground on a Supreme Court that seems defined by 5-4 decisions falling along predictable ideological lines. Although the Justices differed on their precise reasoning, this very pro-privacy decision was unanimous.

While I’ve been critical of some of the trends the Supreme Court has been taking in recent years, the Roberts court has been pretty consistent in upholding the 4^th Amendment. And this is a trend that we should all be happy about.