But what happens when this bulwark against misinformation is absent? If no one disagrees with the position that the misinformation supports, then it is unlikely that the misinformation will be debunked and the position challenged. This can lead to the formation of fallacious conventional wisdom. Even in this case, however, persons with a particular interest in the truth might still challenge the falsity, even if it supports one of their opinions. There is still some chance for the truth to emerge in cases like these.

Unfortunately, this usually is not the end of the story. People rarely take these sorts of criticisms in stride. Instead, they assume that someone who points out a problem with their argument is not “on their side” or, even further, that they support its antithesis. And if the other “side” is thought to be dangerous, evil or otherwise beyond the pale, the truth seekers can quickly become demonized and their voices marginalized.

While merely irritating in personal exchanges, this can lead to disaster when it occurs on a larger scale. The recent history of our foreign policy is especially instructive.

In the wake of its disastrous outcome and resultant unpopularity, it is easy to forget how pervasive the support for the Iraq war was in 2002 and early 2003. A majority of the Senate Democrats voted for the war resolution, and many outlets of the “liberal” media uncritically parroted the Bush administration’s pro-war arguments. Our public discourse became a one-sided echo-chamber, where pro-war liberals and pro-war conservatives reached across the aisle on cable news political programming to demonize war opponents as apologists for Saddam’s criminal brutality.

These opponents, of course, were not making excuses for Saddam—instead, they had weighed the arguments in favor of the war and found them wanting. The inspectors had not found WMDs and were still searching when we invaded, and many feared that deposing Saddam would lead to chaos in Iraq and destabilization in the Middle East as a whole. But rather than engaging with these criticisms, war cheerleaders attacked war opponents as anti-American, “objectively pro-Saddam” pacifists.

You might think that the American media and its pundits would have learned something from this, but that would make far too much sense.

The latest example of this phenomenon took center stage in the recent presidential campaign. After the recent conflict between Russia and Georgia over the separatist South Ossetia region, our pundit class quickly coalesced around the opinion that Russia was an unequivocal imperialist aggressor and that Georgia was a hapless and innocent fledgling democracy bravely defending its freedom. Before even bothering to learn the facts, John McCain, never missing an opportunity for theatrics, breathlessly declared that “we are all Georgians now.” And Obama, who was ridiculed for being too “even-handed” in his initial assessment of the crisis, quickly backpedaled to only inches left of McCain.

Many people have since pointed out that the situation is far more complex—that Georgia played a role in igniting the conflict by its aggression against South Ossetian separatists and Russian peacekeepers and that the testimony offered by Georgians does not square with the observations of independent monitors like the Organization for Security and Cooperation in Europe. But just as in the days before the Iraq war, these critics are not given a voice in the debate and are accused of having sympathies for autocratic governments.

This is manifestly absurd. As Glenn Greenwald has pointed out, “as a matter of the most basic logic, one can find Government X repellent—and even find its response to unwarranted provocations excessive and wrong—and simultaneously object to being lied to about what Government X has done or is doing.”

The lack of any perspective or self-awareness on the part of our media in this case is disheartening, shocking and frankly quite frightening. If they can’t learn the lessons of a fiasco that hasn’t even ended yet, what hope is there that we will avoid war the next time?