From the Fourth Amendment to George Orwell’s Nineteen Eighty-Four, and from the Electronic Communications Privacy Act to films like Minority Report and The Lives of Others, our law and culture are full of warnings about state scrutiny of our lives. These warnings are commonplace, but they are rarely very specific. Other than the vague threat of an Orwellian dystopia, as a society we don’t really know why surveillance is bad and why we should be wary of it. To the extent that the answer has something to do with “privacy,” we lack an understanding of what “privacy” means in this context and why it matters. We’ve been able to live with this state of affairs largely because the threat of constant surveillance has been relegated to the realms of science fiction and failed totalitarian states.

But these warnings are no longer science fiction. The digital technologies that have revolutionized our daily lives have also created minutely detailed records of those lives. In an age of terror, our government has shown a keen willingness to acquire this data and use it for unknown purposes. We know that governments have been buying and borrowing private-sector databases, and we recently learned that the National Security Agency (NSA) has been building a massive data and supercomputing center in Utah, apparently with the goal of intercepting and storing much of the world’s Internet communications for decryption and analysis.

Although we have laws that protect us against government surveillance, secret government programs cannot be challenged until they are discovered. And even when they are, our law of surveillance provides only minimal protections. Courts frequently dismiss challenges to such programs for lack of standing, under the theory that mere surveillance creates no harms. The Supreme Court recently reversed the only major case to hold to the contrary, in Clapper v. Amnesty International USA, finding that the respondents’ claim that their communications were likely being monitored was “too speculative.”

But the important point is that our society lacks an understanding of why (and when) government surveillance is harmful. Existing attempts to identify the dangers of surveillance are often unconvincing, and they generally fail to speak in terms that are likely to influence the law. In this Article, I try to explain the harms of government surveillance. Drawing on law, history, literature, and the work of scholars in the emerging interdisciplinary field of “surveillance studies,” I offer an account of what those harms are and why they matter. I will move beyond the vagueness of current theories of surveillance to articulate a more coherent understanding and a more workable approach.

At the level of theory, I will explain why and when surveillance is particularly dangerous and when it is not. First, surveillance is harmful because it can chill the exercise of our civil liberties. With respect to civil liberties, consider surveillance of people when they are thinking, reading, and communicating with others in order to make up their minds about political and social issues. Such intellectual surveillance is especially dangerous because it can cause people not to experiment with new, controversial, or deviant ideas. To protect our intellectual freedom to think without state over-sight or interference, we need what I have elsewhere called “intellectual privacy.” A second special harm that surveillance poses is its effect on the power dynamic between the watcher and the watched. This disparity creates the risk of a variety of harms, such as discrimination, coercion, and the threat of selective enforcement, where critics of the government can be prosecuted or blackmailed for wrongdoing unrelated to the purpose of the surveillance.

At a practical level, I propose a set of four principles that should guide the future development of surveillance law, allowing for a more appropriate balance between the costs and benefits of government surveillance. First, we must recognize that surveillance transcends the public/private divide. Public and private surveillance are simply related parts of the same problem, rather than wholly discrete. Even if we are ultimately more concerned with government surveillance, any solution must grapple with the complex relationships between government and corporate watchers. Second, we must recognize that secret surveillance is illegitimate and prohibit the creation of any domestic-surveillance programs whose existence is secret. Third, we should recognize that total surveillance is illegitimate and reject the idea that it is acceptable for the government to record all Internet activity without authorization. Government surveillance of the Internet is a power with the potential for massive abuse. Like its precursor of telephone wiretapping, it must be subjected to meaningful judicial process before it is authorized. We should carefully scrutinize any surveillance that threatens our intellectual privacy. Fourth, we must recognize that surveillance is harmful. Surveillance menaces intellectual privacy and increases the risk of blackmail, coercion, and discrimination; accordingly, we must recognize surveillance as a harm in constitutional standing doctrine. Explaining the harms of surveillance in a doctrinally sensitive way is essential if we want to avoid sacrificing our vital civil liberties.

I develop this argument in four steps. In Part I, I show the scope of the problem of modern “surveillance societies,” in which individuals are increasingly monitored by an overlapping and entangled assemblage of government and corporate watchers. I then develop an account of why this kind of watching is problematic. Part II shows how surveillance menaces our intellectual privacy and threatens the development of individual beliefs in ways that are inconsistent with the basic commitments of democratic societies. Part III explores how surveillance distorts the power relationships between the watcher and the watched, enhancing the watcher’s ability to blackmail, coerce, and discriminate against the people under its scrutiny. Part IV explores the four principles that I argue should guide the development of surveillance law, to protect us from the substantial harms of surveillance.