Voltaire once said, “I may disapprove of what you say, but I will defend to the death your right to say it.” But why do we care so much about allowing every moron, bigot and hack to express whatever stupid, offensive or erroneous thought comes into his head? What’s the point of free speech anyway?

There are, of course, many answers to this question. The First Amendment to the Constitution demands that Congress “pass no law … abridging the freedom of speech.” Allowing people to express themselves any way they choose shows our society’s great respect for individual liberty. It is easier to achieve consensus in a democracy when opinions are freely exchanged back and forth. But the most famous answer to the question is the one made famous by John Stuart Mill more than a century ago. According to Mill, the great value of free speech is that it creates a competitive “marketplace of ideas” from which truth inevitably emerges, refined and strengthened by its struggle with all the flawed viewpoints residing in the marketplace.

Mill’s theory may be appealing on an abstract intellectual plane — but does it accurately describe the world we live in? Does truth tend to win out over falsehood in today’s America? A look at the public’s opinions on the most prominent issues of the day suggests that the answer is no. According to a recent report by the Program on International Policy Attitudes (PIPA), 57 percent of Americans think that Iraq either was “directly involved in carrying out the Sept. 11 attacks,” or that it “gave substantial support to al-Qaeda.” A similar proportion believes that world opinion was broadly supportive or neutral toward the United States’ decision to invade Iraq. And one quarter of Americans is actually under the impression that the United States has discovered stockpiles of weapons of mass destruction in Iraq since the end of the war. Confusion also reigns on many domestic issues, with the public uncertain about the size of the federal deficit and the distribution of the Bush administration’s tax cuts. Mill’s marketplace of ideas, it seems, is badly malfunctioning.

There are several explanations why truth is not emerging as effortlessly from the modern American political discourse as Mill would predict. First, people are often too busy with their daily lives to rigorously evaluate the endless facts and opinions that bombard them. Second, even when they invest the time and effort to assess the political landscape, they tend to do so through the prism of their existing preconceptions and biases.

Third, and most problematically, media coverage makes it near impossible for even the most conscientious and rational observer to come to accurate conclusions about the world around him. In their endless quest to draw viewers, television channels focus on the trivial but telegenic — Dean’s “scream,” for example — and avoid serious policy issues. The print media is more substantive, but still overemphasizes the ups and downs of the political horse race; and, thanks to its credo of fair reporting, gives equal credence to viewpoints of radically divergent merit. When a station or newspaper holds a thinly veiled ideological preference, the consequences for the Millsian marketplace are even graver. Eighty percent of the viewers of “fair and balanced” Fox News, for instance, had major factual misperceptions about the war in Iraq, compared to 47 percent of newspaper readers and just 23 percent of PBS/NPR viewers. Partisanship, it appears, compounds the innate problems that an audience-seeking mass media poses for the emergence of truth.

None of this is any reason to curtail freedom of speech — which, after all, rests on other foundations in addition to the marketplace of ideas. But it is reason to seek to facilitate the emergence of truth from the modern American political discourse. Since people are unlikely to suddenly become more attentive to politics or more rational in their understanding of the world, the media must be the focus of any such effort. Assuming that actual censorship is a nonstarter, then, we should resist the further consolidation of media organs, cultivate serious independent media voices, insist on strict firewalls between media units and the political interests of their parent conglomerates, and consider expanding the public service requirements for television stations. None of these steps will magically eliminate the many impediments to the smooth functioning of the marketplace of ideas. But together they might deepen our appreciation of why free speech matters, and why Voltaire was willing to die to defend it.

Nicholas Stephanopoulos is a first-year student at Yale Law School. His column appears on alternate Mondays.