Fractional Originalism and the Fourth Amendment's Trespass Test

by Matthew Tokson

In recent years, the Supreme Court has adopted a trespass test in Fourth Amendment law, holding that the Fourth Amendment applies to government encroachments on a person’s property, among other things. This addition to Fourth Amendment law was mostly seen as a victory for privacy advocates. For example, see last week’s ruling by a federal court that chalking the tires of parked cars to determine if they’d overstayed the parking limit was a Fourth Amendment search, requiring a warrant. Decisions like this seem quirky but ultimately favorable to criminal defendants and citizen privacy. 

In reality, however, these cases can result in police using far more intrusive and technologically advanced forms of surveillance. The trespass rule does not necessarily bolster privacy on net. And it has already made something of a mess of Fourth Amendment law. Arbitrary, poorly designed rules eventually start to produce bad outcomes, no matter how benign they seem at first.

The question of what constitutes a Fourth Amendment “search” is complicated. But it used to be simple, mostly because the Fourth Amendment didn’t protect very much. Before 1967, the Fourth Amendment only applied to a trespass (or seizure) of the “persons, houses, papers, and effects” mentioned in the Amendment. This meant that, among other things, the government could wiretap its citizens at will without implicating the Fourth Amendment. It also led to increasingly ridiculous results in cases involving newer recording technologies. One pair of cases famously held that bugging someone’s conversations violated the Fourth Amendment if the microphone touched their heating duct but was perfectly fine if the microphone stayed just outside their walls.

In the late 1960s, the Supreme Court changed all that, eventually adopting a test that finds a Fourth Amendment search whenever a person’s “reasonable expectation of privacy” has been violated. Reasonable expectation of privacy is a complicated, amorphous concept, but in general, when the government captures intimate information, or a large amount of information in general, courts will find that a person could have reasonably expected that such information would remain private. 

Then the Supreme Court made things even more complicated. In a 2012 case involving a GPS tracker that the police attached to a car, the Supreme Court revived a version of the old trespass test and added it to the existing reasonable expectation of privacy test. Fourth Amendment search law today is an unwieldy hybrid of the two tests, and courts must examine whether there is any physical encroachment without license on a person’s property, and if not, whether the government has violated their reasonable expectation of privacy. 

The trespass test itself promptly got messy and vague. In Florida v. Jardines, the Supreme Court held that police violated the Fourth Amendment when they walked onto a suspect’s yard accompanied by a drug-sniffing dog. Doing so might not technically have been an actionable trespass, but it violated the implied license that homeowners give to visitors, breaching the complex web of social norms that surrounds yards and guests. In the lower courts, the trespass test has posed numerous difficult and strange questions, like is it a Fourth Amendment search to try a key in a lock, or to press the button on a garage door opener? What seemed like a clear-cut test has been anything but.

There are numerous other problems with the trespass test. It is arbitrary, especially in the modern world, basing constitutional protections on whether a recording device touches something rather than the private data it records or the government abuses it enables. It incentivizes police to use panoptic non-physical surveillance methods like license plate readers or CCTV instead of less invasive methods like chalking tires. It promotes a propertarian view of corporate data, impeding local governments that seek to regulate large tech companies and criminal defendants who want to challenge sentencing or other algorithms used against them at trial. It is overbroad in some areas, motivating courts to eliminate the warrant requirement for some searches rather than prevent the police from engaging in surveillance that happens to involve de minimis physical touching. In other words, rather than enhancing privacy, it simply gives the police a victory at the second step of the Fourth Amendment analysis rather than the first, and further erodes the probable cause and warrant requirements that are the bulwark of Fourth Amendment protection.

Then there is the originalist aspect of the trespass test. Arguably, the trespass approach is grounded in the original meaning of the text of the Fourth Amendment in a way that the reasonable expectation privacy test isn’t. But the trespass test fails as originalism as well. It is, at best, what I’ll call fractional originalism, where a judge selectively grafts only a small fraction of an originalist concept onto a larger doctrine, creating a non-originalist hybrid that produces desirable outcomes but has no connection to original meaning. To be sure, fractional originalism is often preferable to genuine originalism on several grounds. For example, the current trespass rule is preferable on consequentialist grounds to Justice Thomas’s more coherent originalist interpretation of the Fourth Amendment, which would largely eliminate meaningful Fourth Amendment protection for anything. But fractional originalism is not originalism in any sense that matters, and it cannot be justified using the arguments that might justify originalism. 

The modern trespass test is not originalism either. Which is fine by me; I’m not an originalist. But many Justices on the Court are, in theory, and so some discussion of original meaning is warranted here. At the time of the Founding, the Fourth Amendment supported the common law of trespass, and trespass lawsuits were the means by which citizens restrained constables from harassing innocent homeowners. The Amendment prevented these constables, who were temporarily appointed and drawn from the lower rungs of colonial society, from securing general warrants that would allow them to search any house they pleased. If a constable unlawfully searched your house for seditious materials, you could sue him for damages. Colonial juries sometimes granted punishingly high damage awards against such ruffians.  

There are several, substantial differences between the modern trespass test and the original meaning and scope of the Fourth Amendment. For example, the practical scope of the Fourth Amendment at the founding did not extend further than actionable torts. A de minimis physical touching like placing a small object on a car or stepping onto a walkway with a dog would not give rise to a trespass action in the first place. But under the modern test, de minimis trespasses can justify exclusion of evidence in a criminal trial. For another example, Chad Flanders has convincingly argued that curtilage at the founding did not refer to the land surrounding a house, but only the buildings on that land, which would place yards outside of the “persons, houses, papers, and effects” mentioned by the Amendment. Yet Jardines depends heavily on the evolving concept of curtilage as including yards and other areas where the private activity of the household may occur. These are just a few examples; there is much, much more. The modern trespass test has little to do with the original meaning of the Fourth Amendment, and in no way resembles founding-era practice or original understandings of the Amendment’s text. 

Reviving the trespass test allowed the Court to resolve a GPS tracking case more easily in 2012. Since then, it has muddled Fourth Amendment doctrine and caused a variety of problems for lower courts, law enforcement, defendants, and anyone trying to understand criminal procedure. It’s time for the Court to consider abandoning it, just as it abandoned the ridiculous heating duct cases decades ago.