Theoretically, any idea or practice that's widely accepted, but which one would like to call into question, could be described as politically correct (PC). But in practice it is not an equal-opportunity sneer; it's almost always wielded by those with more power in order to dismiss objections (to language, policies, or behaviors that harm or offend people) offered by those with less power, and thus to shut them up.

Thus, someone who calls attention to the fact that every single person selected for a particular distinction happens to be white can be written off as PC. Likewise, an individual who objects to the use of the word girl to describe a grown woman. Or who requests accommodations for people with disabilities. Or who points out that what has just been said about love seems to assume that everyone in the world is heterosexual. In short, any move to be more inclusive in extending consideration or respect, anything that challenges the comfortable world in which certain people quietly maintain their privileged status, may be met with a roll of the eyes and a sarcastic "Oops. I forgot we have to be politically correct here …"

To classify something as PC isn't just to say that one would prefer not to deal with it. It implies that what might be called a liberal sensibility represents the conventional wisdom (of which the challenger is attempting to remind us). But I'd argue that exactly the opposite is true: Our political system and the norms of our culture are largely built on an edifice of conservative beliefs regarding power, tradition, religion, and nationalism, many of them invisible to us precisely because they're so widely and uncritically unaccepted.

If "PC" were just a neutral pin for puncturing any balloon thought to be overinflated, then it might be applied to, say, the view that when the U.S. invades or occupies other countries, it is doing so in the interest of spreading democracy -- or that soldiers who participate in these military adventures around the world are "defending our country." But when did you last hear someone say with a smirk, "I know, I know. It's politically correct to 'Support Our Troops.' But I happen to believe…"?

The same is true of many other assumptions regarding patriotism (attitudes toward our national anthem or treatment of the flag, for example) as well as beliefs overwhelmingly shared about how to raise children, teach students, or manage employees that could be described as deeply conservative -- and that one questions at one's peril.

Imagine someone saying, "Hey, you want proof that political correctness is out of control? Try asking why Christmas is a national holiday. Try exploring how it is that only one person in a classroom is called by her last name. Try challenging the assumption that workers need to be motivated with incentives. These things are all off-limits because they're too PC." If the label seems odd in these contexts it's because "PC" works in only one direction: from right to left.

In addition to defending a conservative status quo from inconvenient challenges -- again, without one's having to offer a substantive defense -- the term serves another important function: self-congratulation. To say that x is PC is to praise oneself for having the courage to see things otherwise. And to warn that something isn't PC is to commend it -- or, in many cases, oneself -- as bold and refreshing. "Now I know what I'm about to say is politically incorrect, but . . ." sounds like a cautionary preface, but it actually invites us to view the speaker as daring even though what follows may be merely conservative. Or offensive.

In fact, no matter how despicable something might be, opposition to it can always be dismissed by framing it as political correctness. In 2004, a book about Benjamin Franklin was reviewed in the New York Times Book Review by a staff writer who made it clear he was an admirer of Franklin but then added that "the politically correct would most likely hector him if they could. For Franklin was a slaveholder." Even opposition to slavery apparently qualifies one as merely PC.

By the same token, no matter how conservative you are, there's always the risk that someone to your right may fling the label at you. When, in 1996, the presidential campaign of Republican candidate Patrick Buchanan tried to distance itself from the unsolicited support of neo-Nazi David Duke, Buchanan was accused by a Duke spokesman of -- yup -- political correctness. (And if Pat Buchanan can be called PC, truly none of us is safe.)

But the label serves no legitimate purpose regardless of whom -- or what -- it is used to disparage. Those who merely find it a convenient, perhaps ironic, shorthand ought to consider the political ramifications of its use. And even people who approve of those ramifications ought to be offering logic and evidence to support their views rather than depending on an unpleasant label to bully into silence those with whom they disagree.