If you ever find yourself desperate for a conversation starter, you might offhandedly drop the observation that the word label is related to lap, which was originally a piece of cloth than hangs down at the bottom of a garment. A little part of that meaning survives in the way we talk about political labels, with the implication that they're merely tags tacked onto things for convenience. We don't ordinarily say that duck is a label for a kind of waterfowl. Duck is just a name. Whereas calling a word a label implies that it distorts or oversimplifies the category it's attached to. You hear people say,  "I don't believe in labels," but nobody ever says "I don't believe in names."

Even so, we can't help imputing a reality to labels. Putting the Porsche name on a pair of sunglasses can invest them with the same panache we associate with the company's cars, even if we know perfectly well that the two have nothing in common. That's the principle that leads everyone to claim a political label when it's riding high in the saddle. At the heyday of liberalism in the 1950's and 1960's, everybody was happy to wear the label, from Stevenson to Eisenhower to the Dixiecrats, and nobody was too interested in debating its essence. As the critic Lionel Trilling wrote, liberalism was merely a tendency, not a body of doctrine.

That began to change in the 70's and 80's, as a combination of liberal missteps and conservative attacks drove the liberals and their label from center stage. Politicians who would once have proudly owned up to the label began to flee from it. Old tribal differences no longer seemed important: people stopped distinguishing between progressive liberals, moderate liberals, pragmatic liberals, Northern liberals, traditional liberals, and New Deal liberals. Now the label suggested only a small band of diehards clinging to the edges of the political continent.

Since then, of course, it's the conservative label that has swollen to contain multitudes, particularly as the ideological poles were redefined to add social issues that no one much cared about when the liberal-conservative opposition first emerged in the New Deal era. A 2005 Harris poll showed that Americans are much more likely to identify people as being liberals or conservatives according to their views on abortion or gay rights than on whether they want to cut taxes.

That's why the media invariably describe anti-abortion or pro-gun Democrats like James Webb, Jon Tester, and Bob Casey as conservatives, even if they actually campaigned on the kind of economic populism that defined liberalism a couple of generations ago. In fact the label "social liberal" is regarded as almost a redundancy these days, as if it went without saying. Fifteen or twenty years ago, the phrase was as frequent as "social conservative" in the media. Now it's outnumbered by "social conservative" by almost 20 to 1.

The mark of a successful label is that we feel the need to make distinctions and qualifications among the many groups that are laying claim to it. That's why the conservative label has attracted such a clutch of modifiers -- social, economic, small-government, fiscal, libertarian, neo-, and paleo-. But the big-tent conservative label began to fray as the administration's poll ratings declined precipitously, and since the elections it appears to be coming apart at the seams.

True, everybody on the right is quick to claim that the voters hadn't repudiated true conservatism: the Republicans would still be in power if they had only been faithful to core conservative principles. But each constituency has a different idea of what those core principles are and how they were betrayed. For James Dobson of Focus on the Family, the Republicans' downfall was their failure to do more to preserve moral values; for Dick Armey it was their refusal to hold the line on spending. For National Review's Rod Dreher, the problem was the Republicans' focus on money and power rather than a concern about character, which is the mark of true conservatism. And for William F. Buckley, it was a failed Iraq adventure that's signaled the absence of an "effective conservative ideology."

Whenever you hear somebody declaiming about "true conservatism" or "genuine liberalism," you can assume the argument has more to do with labels than ideas. There's a fear on the right that the voters' dissatisfaction with Republicans may translate into disenchantment with the conservative label itself, just as the liberal label was tarnished 40 years ago by its association with Vietnam and the civil-rights backlash.

The immediate reaction is for each of the constituencies that have been wearing the conservative label to claim the right to its sole use and discredit all the pretenders who have been wearing it improperly. In the next election, it's a safe bet that people who call themselves conservatives will be doing a lot more explaining and qualifying than they did the last time around.

True, the conservative label is still a very long way from disintegrating the way the liberal label did after Vietnam. The right doesn't really have to worry seriously until Republicans start saying things like "I don't believe in labels," always a sign that a label is becoming more of an inconvenience than a convenience.

The beauty of a label is that it smoothes over the complexities and corrugations of the world to create an impression of common purpose. But that's also why a label can become an embarrassment when it comes to apportioning blame. At that point, people are just as happy to drop it in someone else's lap.