One would think privacy was a concept that Justice Antonin Scalia disliked. After all, how could a textualist, who firmly believed in lawyers’ obligation to follow the text, respect a concept as nebulous and blurry edged as privacy? A concept whose very meaning continues to befuddle lawyers, political philosophers and social scientists more than a century after it was introduced into legal jargon by Louis Brandeis, another Supreme Court giant to come? How could an originalist who ordered judges to respect the original meaning of the Constitution embrace a right not mentioned once in the revered text, but rather introduced into American constitutional law through creative judicial interpretation identifying “penumbras of privacy” in the constitutional text?

And yet Justice Scalia, as his close friend and frequent disputant on the bench, Justice Ruth Bader Ginsburg, said, was “one of the most pro-Fourth Amendment judges on the court.”

In a way, Justice Scalia’s stance towards privacy encapsulates the prevailing approach of the American legal system: suspicion of government surveillance coupled with tolerance for corporate data practices. This tolerance may itself be the result of misgivings about government regulation. In some of his most important Fourth Amendment decisions, Scalia sided with the liberal justices of a split court, delivering opinions that curtailed government power, particularly in light of newly introduced intrusive technological breakthroughs.

In Kyllo v. United States, Scalia, writing for a 5-4 majority, which included three of the most liberal justices on the court (as well as his conservative colleague Justice Thomas), ordered the police to get a warrant before performing thermal imaging of a suspect’s home. In doing so, he rejected the government’s argument that individuals had no expectation of privacy outside the confines of their homes. A machine that sees through walls, reasoned Scalia, in order to capture the heat emanating from lamps used to grow marijuana, infringes upon individuals’ reasonable expectation of privacy, even when law enforcement is positioned outside the house. The Kyllo rationale is crucial to establishing individuals’ rights in an age where even the most inconceivable technological breakthroughs become a reality in the blink of an eye, threatening society with a slippery slope of surveillance pervading every aspect of our daily lives.

In United States v. Jones, probably the most important Fourth Amendment case since the 1967 decision in Katz v. United States, Scalia, writing for the majority, required the police to obtain a warrant prior to attaching a GPS tracker to a suspect’s car. While basing his opinion on narrow property grounds, Scalia rejected the government’s claim that individuals had no expectation of privacy while driving in broad daylight on city streets. Besides its erosion of the third-party doctrine, based on the opinion of a plurality of concurring justices, Jones sets an important precedent for the concept of privacy in public, a notion once viewed as paradoxical but now increasingly essential in public spaces monitored by ubiquitous cameras, phones and Internet of Things devices.

In Florida v. Jardines, Scalia, again writing a 5-4 decision supported by three liberal justices and Justice Thomas, held that police use of a trained detection dog to sniff for narcotics on the front porch of a private home was, indeed, a search within the meaning of the Fourth Amendment. The consequences of Jardines, as well as other dog sniffing cases, are far broader than for just narcotics searches. They implicate suspicion-less searches by other mechanized sniffers – for example, think about keyword searches of communications contents and metadata for cybersecurity or intelligence purposes.

While upholding suspects’ Fourth Amendment rights, however, Justice Scalia viewed with disdain the commotion around consumer privacy, particularly online. In one well-publicized exchange, he sparred with Fordham Professor Joel Reidenberg around the importance of informational privacy. The kerfuffle started when Reidenberg attended a conference in which Scalia dismissed online privacy as overblown, quipping, “Every single datum about my life is private? That’s silly.” Reidenberg reacted by assigning his information privacy class a provocative assignment, to create a digital dossier about Scalia from what could be found via publicly available sources on the web. Perhaps not practicing what he had preached, Scalia fumed when he discovered the 15-page dossier of his personal data, which included his home address and phone number, his wife’s personal e-mail address and the TV shows and food he prefers.

“It is not a rare phenomenon that what is legal may also be quite irresponsible,” Scalia seethed. “Reidenberg’s exercise is an example of perfectly legal, abominably poor judgment.”

Regardless of political opinion, few will dispute Scalia’s presence as a towering intellectual force on the bench. His writing style was commanding, frequently acerbic and always colorful. In Kyllo, for example, he wrote that the government’s thermal imaging device, “The Agema Thermovision 210, might disclose, for example, at what hour each night the lady of the house takes her daily sauna and bath — a detail that many would consider ‘intimate’.” In Jardines, he summarily dismissed the government’s arguments about houseguest etiquette, which included deploying a canine sniff on the front porch of a home. He writes, “This implicit license typically permits the visitor to approach the home by the front path, knock promptly, wait briefly to be received, and then (absent invitation to linger longer) leave. Complying with the terms of that traditional invitation does not require fine-grained legal knowledge; it is generally managed without incident by the Nation's Girl Scouts and trick-or-treaters.”

Privacy is a complex legal right and social construct, which transcends traditional political divisions and can enable policymakers to reach across the aisle. Justice Scalia’s legacy in this space, while complicated, has left a mark for years to come.