The Fourth Amendment guarantees the "right of the people to be secure in their persons, houses, papers, and effects against unreasonable searches." Why did the Framers care so much about this "right" that they thought to put it into the Constitution? What was it about "searches" that generated their concern? Most obviously, a search of your house or person is intensely disruptive and humiliating. To have officers of the government ransack your home, rummage through your desk, and empty your handbag is surely unpleasant. Moreover, such a search invades your personal property in an elemental way. "Who are you to storm into my home in this way?!" Understandably, then, the Framers declared such searches by government officials constitutionally permissible only if they were "reasonable."
With the advent of electronic bugging and wiretapping, courts found themselves in a quandary. Such methods of surveillance are undertaken in secret, so they are neither hassling nor humiliating. And because they can be implementing without entering onto your property, they don't implicate your property rights. Thus, for some forty years the Supreme Court held that such methods of surveillance did not constitute a "search" within the meaning of the Fourth Amendment. Unlike more traditional searches, the government could therefore employ electronic surveillance without complying with probable cause and warrant requirements of the Fourth Amendment.
It wasn't until1967 that the Supreme Court held that the Fourth Amendment should be understood as protecting "the people" not only against disruption, humiliation, and physical invasion of their property, but also against intrusions into their privacy. This was a huge leap, and although it may seem obvious today, it was neither inevitable nor uncontested. The proponents of this broader understanding of the Fourth Amendment argued, in effect, that it was a mistake to construe the Fourth Amendment as concerned only with hassle, humiliation, and property. Those characteristics were all present traditional eighteenth-century searches, but so too was invasion of privacy. After all, they observed, searching a person's home or office invades his privacy as much as his property.
The critical step, though, was not the observation that traditional searches invade privacy, but that something could be a "search" even if it was not disruptive, humiliating, or invasive of private property. In this new understanding, the invasion of privacy was itself sufficient to trigger the Fourth Amendment. Thus, under this view, a simple wiretap, in which a government official surreptitiously listens to a telephone call by splicing into the telephone company's line, would now be considered a "search," and would henceforth be constitutionally permissible only if it was authorized in advance by a search warrant issued by an independent judicial officer who had found that there was probable cause to believe the wiretap would turn up evidence of crime - the same constitutional requirements that had traditionally governed searches of a person's home or office.
The current debate over NSA spying has caused some people to wonder, "What's the big deal about electronic surveillance, anyway?" As I've suggested above, this is not at all a crazy question. If the government surreptitiously listens to your phone calls or reads your emails, you're not hassled, you're not humiliated, and there's no interference with your property. If you haven't done anything wrong and have nothing to hide, why should you care if the government looks over your shoulder? Perhaps the Court was wrong to extend the Fourth Amendment to electronic surveillance.
The response, of course, is that we value our privacy. But why? Even if a government official (or a computer) learns who you're dating or what movie you saw last week, the NSA has no interest in such mundane matters. Such stuff is all just miscellaneous garbage the government has to wade through in order to find what it's looking for - the terrorists. What it's searching for is not backyard gossip, but the evildoers in our midst. So, even if all the other stuff gets heard, read, and recorded, why should you care? It's not enough to say, "it invades my privacy." You have to explain why that matters.
So, here are three possible answers for your consideration. If they're not persuasive, then perhaps you should stop fretting about the NSA and, indeed, about electronic surveillance generally. First, perhaps privacy matters because it's important for you to be able to lead your everyday life without the sense that the government is constantly peering over your shoulder and preserving for posterity your every word and deed. This is a point about the ordinariness of everyday life. Maybe merely being watched, and knowing we're being watched, somehow undermines and inhibits our sense of freedom. Maybe part of being free means knowing you're not being watched.
But why would you care about being watched if you're not a criminal and the only thing the watchers care about is whether you are? If you're engaging in criminal acts, then you have no right to hide that behavior, and if you're not engaging in criminal acts, then you have nothing to fear from the surveillance. Maybe it's just a myth that knowing you're being watched impairs your sense of freedom. If you don't do or say anything the watchers care about, maybe you'll just forget they're even there.
This brings me to my second argument. With good reason, we shouldn't trust the government to care only about criminal acts. Once the government can gather all sorts of other information about you (for example, who your friends are, what books you read, what petitions you've signed, who you sleep with), it then has the capacity to use that information against you in all sorts of ways that have nothing to do with catching terrorists. Certainly, we've seen this throughout history. Information is power, and power can (and usually will) be abused. Suppose you have to consider that every act, every phone call, every email is permanently preserved in government computers and thus accessible even many years from now to those officials who will decide whether to hire you for a government job, oppose you for elective office, admit you or your child to a public university, or audit your taxes. Might this have an effect on your conduct and conversations?
To get a sense of this phenomenon, you need only recall what happened to people who in the 1930s joined organizations that were then perfectly lawful but that twenty years later became known as "Communist-front" organizations. The lesson of that experience produced the stifling conformity of the '50s as individuals became afraid to anything out of the ordinary. And, of course, it is political freedom that is most likely to get caught in this net.
Third, perhaps this sort of privacy matters because in a self-governing society we must vigilantly reinforce and preserve the sense of independence and autonomy of the individual. For a self-governing society to function, the citizen must feel that he is the governor, nor the subject. Perhaps it is difficult to feel like the governor when your government has the power to watch your every move. Perhaps limiting the government in this way is essential the well-being of democracy itself. Certainly, life in the former Soviet Union, with its pervasive government surveillance, crushed the life out of "the people." If we do that to ourselves, we will be worse than the terrorists.