When it comes to privacy, expectations matter.

“Because the Fourth Amendment protects people rather than places, its reach cannot turn on the presence or absence of a physical intrusion into any given enclosure.” - Katz v. United States

One Catch-22 with innovation and the digital age is that technology inevitably outpaces the law. Tracking systems like GPS allow government officials to follow people in their cars or homes easily; new amplification technologies enable police to overhear or view previously unmonitored areas; and sophisticated electronic hacks permit authorities to override even password-protected databases. While it might be nice if we were to regulate all of these areas, legislative remedies are simply too narrow and too belated to offer any real efficacy against these changes.

The risk then, it seems, is that our public areas become near infinite. How, when search engines catalogue digital information near-ubiquitously, can we have any expectation of electronic privacy? How can we expect any privacy protection when, as we extend wires from our homes to other homes, our spaces become less and less confined? If you’re Justice Black, perhaps you believe that we can’t have any defenses; we can only protect “tangible things with size, form, and weight.”

Such a reading, however, of the Fourth Amendment, nullifies its very Constitutional purpose, affronting the intent of the Framers. From our cell phone relays to our wifi connections, we unquestionably emit far more public signals in the digital age. But that doesn’t mean we drop our Constitutional liberties at the gates of the modern era! As Justice Brandeis says in the Olmstead dissent, “in the application of a Constitution, our contemplation cannot only be of what has been, but of what may be.” Let us not forget, for instance that “in plain view” means not just that something is “viewable,” but that it is plainly visible.

Where then do we draw the line between modern public and private space? Because making this distinction will change so much based on the type of the technology, Katz gets it right: we must look toward the people involved, specifically whether or not the people have a reasonable expectation of privacy. For example, as Trulock attempts to make clear, whenever a person establishes a digital password, it is clear that they are trying to establish privacy. It seems that we can distinguish between my password-protected Gmail files and my posts on a public forum like Blogspot—I certainly have an expectation of privacy in the former case where I do not in the latter. Thus, shielding my Gmail account from unwarranted searches is more important than protecting my Blogspot posts.

In Katz, Justice Harlan tries to establish a two-prong test for privacy: (1) governmental action must contravene an individual's actual, subjective expectation of privacy; (2) that expectation of privacy must be reasonable, in the sense that society in general would recognize it as such. The Supreme Court has since (in my opinion, wisely) adopted this test.

In the modern era, when we can never truly protect ourselves from technological innovations and breaches, we need to look toward areas where we societally expect to have privacy rather than just those areas where we can physically secure. When no combination of Firewalls and passwords can ever protect our private spaces from others, we need to look towards the law as our last safeguard!